:root {
  --color-bg: #f6f7fb;
  --color-surface: #ffffff;
  --color-primary: #4361ee;
  --color-primary-dark: #2746c1;
  --color-accent: #4cc9f0;
  --color-text: #202124;
  --color-muted: #5f6368;
  --color-border: #dfe3eb;
  --radius-lg: 20px;
  --transition: 0.2s ease-in-out;
  font-size: 16px;
}

*,
*::before,
*::after {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
  background: var(--color-bg);
  color: var(--color-text);
  display: flex;
  flex-direction: column;
  min-height: 100vh;
}

a {
  color: inherit;
  text-decoration: none;
}

.muted {
  color: var(--color-muted);
}

main {
  flex-grow: 1;
}

.container {
  width: min(1120px, 92vw);
  margin: 0 auto;
}

.site-header {
  background: var(--color-surface);
  border-bottom: 1px solid var(--color-border);
  position: sticky;
  top: 0;
  z-index: 10;
}

.header-content {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0.6rem 0;
}

.brand {
  display: flex;
  align-items: center;
}

.brand-link {
  display: inline-flex;
  align-items: center;
  gap: 0.75rem;
  font-weight: 600;
  font-size: 1.1rem;
  color: var(--color-text);
}

.brand-logo {
  display: block;
  height: 56px;
  width: auto;
}

.brand-name {
  color: inherit;
  display: inline-flex;
  align-items: baseline;
  gap: 0.15rem;
}

.brand-dot {
  color: var(--color-primary);
  font-size: 0.95em;
}

.main-nav {
  display: flex;
  align-items: center;
  gap: 1rem;
}

.main-nav form {
  margin: 0;
}

.main-nav--staff {
  gap: 0.75rem;
}

.staff-nav-role {
  font-weight: 600;
  color: var(--color-text);
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  background: rgba(67, 97, 238, 0.08);
  padding: 0.35rem 0.85rem;
  border-radius: 999px;
  font-size: 0.95rem;
}

.staff-nav-role strong {
  color: var(--color-primary);
}

.staff-nav-logout {
  margin: 0;
}

.staff-nav-logout .btn {
  margin-left: 0;
}

.nav-greeting {
  color: var(--color-muted);
  font-size: 0.95rem;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.4rem;
  border-radius: 999px;
  padding: 0.65rem 1.4rem;
  font-weight: 600;
  border: 1px solid transparent;
  cursor: pointer;
  transition: transform var(--transition), box-shadow var(--transition),
    background var(--transition), color var(--transition);
}

.btn:focus {
  outline: 3px solid rgba(67, 97, 238, 0.2);
  outline-offset: 2px;
}

.btn-primary {
  background: linear-gradient(135deg, var(--color-primary), var(--color-accent));
  color: #ffffff;
  box-shadow: 0 10px 20px rgba(67, 97, 238, 0.25);
}

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 14px 28px rgba(67, 97, 238, 0.28);
}

.btn-secondary {
  background: transparent;
  border-color: var(--color-border);
  color: var(--color-text);
}

.btn-secondary:hover {
  border-color: var(--color-primary);
  color: var(--color-primary);
}

.btn-outline {
  background: transparent;
  border: 1px solid rgba(67, 97, 238, 0.3);
  color: var(--color-primary);
}

.btn-outline:hover {
  border-color: var(--color-primary);
  background: rgba(76, 201, 240, 0.08);
}

.btn-block {
  width: 100%;
}

.btn-small {
  padding: 0.45rem 1.1rem;
  font-size: 0.9rem;
}

.btn-gradient {
  background: linear-gradient(90deg, #4361ee 0%, #50c9ff 100%);
  color: #fff;
  border: none;
  padding: 0.55rem 1.5rem;
  border-radius: 999px;
  font-weight: 600;
  white-space: nowrap;
  box-shadow: 0 10px 20px rgba(67, 97, 238, 0.2);
  display: inline-flex;
  align-items: center;
  justify-content: center;
  font-size: 0.95rem;
  text-decoration: none;
  line-height: 1;
}

.btn-gradient:hover {
  opacity: 0.95;
}

.btn-gradient.btn-gradient-muted {
  background: linear-gradient(90deg, #9aa5b1 0%, #d7dde4 100%);
  box-shadow: 0 10px 20px rgba(104, 112, 118, 0.2);
}

.btn-gradient.btn-gradient-muted:disabled {
  opacity: 0.85;
  cursor: not-allowed;
}

.hero {
  padding: 4.2rem 0;
}

.hero-content {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 3rem;
  align-items: center;
}

.hero-text h1 {
  font-size: clamp(2.2rem, 4vw, 3.5rem);
  margin-bottom: 1rem;
}

.hero-text p {
  color: var(--color-muted);
  line-height: 1.6;
  margin-bottom: 2rem;
}

.hero-license {
  margin-top: -1rem;
  margin-bottom: 2rem;
}

.hero-license a {
  color: var(--color-primary);
  font-weight: 600;
  text-decoration: underline;
  text-decoration-thickness: 2px;
}

.hero-actions {
  display: flex;
  align-items: center;
  gap: 1rem;
  flex-wrap: wrap;
}

.hero-visual {
  display: flex;
  justify-content: center;
}

.hero-image {
  width: clamp(260px, 32vw, 420px);
  max-width: 100%;
  border-radius: var(--radius-lg);
  box-shadow: 0 14px 32px rgba(31, 38, 135, 0.16);
  border: 1px solid rgba(67, 97, 238, 0.12);
}

.feature-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 1.5rem;
  padding-bottom: 4rem;
}

.feature-card {
  background: var(--color-surface);
  border-radius: var(--radius-lg);
  padding: 2rem;
  border: 1px solid rgba(67, 97, 238, 0.08);
  box-shadow: 0 10px 25px rgba(31, 38, 135, 0.08);
}

.feature-card h2 {
  margin-top: 0;
  font-size: 1.3rem;
}

.feature-card p {
  color: var(--color-muted);
  line-height: 1.5;
}

.auth-wrapper {
  display: flex;
  justify-content: center;
  align-items: center;
  padding: 4rem 1rem;
}

.auth-card {
  background: var(--color-surface);
  border-radius: 16px;
  padding: 2.5rem;
  width: min(420px, 90vw);
  box-shadow: 0 15px 30px rgba(15, 23, 42, 0.12);
  border: 1px solid rgba(67, 97, 238, 0.08);
}

.auth-card h1 {
  margin: 0 0 0.75rem;
  font-size: 1.8rem;
}

.manager-auth-wrapper {
  padding: 4rem 1rem 5rem;
}

.manager-auth-actions {
  margin-top: 1rem;
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}

.manager-auth-actions .btn {
  width: 100%;
}

.manager-auth-back {
  text-align: center;
}

@media (min-width: 560px) {
  .manager-auth-actions {
    flex-direction: row;
    align-items: center;
  }

  .manager-auth-actions .btn {
    flex: 1;
    width: auto;
  }

  .manager-auth-back {
    flex: 0 0 auto;
  }
}

.auth-subtitle {
  color: var(--color-muted);
  margin-bottom: 2rem;
}

.auth-form {
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

.auth-form label {
  font-weight: 600;
  font-size: 0.95rem;
}

.auth-form input {
  border-radius: 12px;
  border: 1px solid var(--color-border);
  padding: 0.75rem 1rem;
  font-size: 1rem;
  transition: border-color var(--transition), box-shadow var(--transition);
}

.auth-form input:focus {
  border-color: var(--color-primary);
  box-shadow: 0 0 0 3px rgba(67, 97, 238, 0.15);
  outline: none;
}

.admin-dashboard {
  padding: 3rem 0 4rem;
  display: flex;
  flex-direction: column;
  gap: 2rem;
}

.admin-dashboard-header h1 {
  margin-bottom: 0.5rem;
}

.admin-dashboard-header p {
  margin: 0;
  color: var(--color-muted);
  line-height: 1.6;
}

.manager-dashboard {
  padding: 3rem 0 4rem;
}

.manager-dashboard .container {
  display: flex;
  flex-direction: column;
  gap: 1.75rem;
}

.manager-dashboard__card {
  background: var(--color-surface);
  border-radius: var(--radius-lg);
  padding: 2rem;
  border: 1px solid rgba(67, 97, 238, 0.08);
  box-shadow: 0 18px 34px rgba(15, 23, 42, 0.08);
}

.manager-dashboard__card--primary {
  background:
    linear-gradient(135deg, rgba(67, 97, 238, 0.12), rgba(76, 201, 240, 0.08)),
    var(--color-surface);
}

.manager-dashboard__header {
  display: flex;
  flex-wrap: wrap;
  align-items: flex-start;
  justify-content: space-between;
  gap: 1rem;
  margin-bottom: 1.5rem;
}

.manager-dashboard__cta {
  display: flex;
  flex-direction: column;
  gap: 0.85rem;
}

.manager-dashboard__helper {
  margin: 0;
  font-size: 0.9rem;
}

.manager-dashboard__list {
  margin: 0.5rem 0 0;
  padding-left: 1.25rem;
  line-height: 1.5;
}

.manager-dashboard__list li + li {
  margin-top: 0.35rem;
}

.manager-messages {
  padding: 3rem 0 4rem;
}

.manager-messages__header {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  gap: 1.5rem;
  margin-bottom: 2rem;
}

.manager-messages__eyebrow {
  margin: 0 0 0.35rem;
  font-size: 0.8rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--color-muted);
}

.manager-messages__meta {
  display: flex;
  flex-direction: column;
  align-items: flex-end;
  gap: 0.5rem;
}

.manager-messages__counter {
  font-weight: 600;
  color: var(--color-primary);
}

.manager-section {
  display: flex;
  flex-direction: column;
  gap: 1rem;
  margin-top: 2.5rem;
}

.manager-section__title {
  display: flex;
  align-items: center;
  gap: 0.75rem;
}

.manager-badge {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-width: 34px;
  height: 34px;
  border-radius: 999px;
  background: rgba(67, 97, 238, 0.12);
  color: var(--color-primary);
  font-weight: 600;
}

.manager-badge--muted {
  background: rgba(95, 99, 104, 0.15);
  color: var(--color-muted);
}

.manager-thread-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 1.25rem;
}

.manager-thread-card {
  background: var(--color-surface);
  border-radius: 18px;
  padding: 1.5rem;
  border: 1px solid rgba(67, 97, 238, 0.09);
  box-shadow: 0 16px 30px rgba(15, 23, 42, 0.08);
  display: flex;
  flex-direction: column;
  gap: 0.85rem;
}

.manager-thread-card--urgent {
  border-color: rgba(244, 67, 54, 0.35);
  box-shadow: 0 20px 38px rgba(244, 67, 54, 0.12);
}

.manager-thread-card__header {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 0.75rem;
}

.manager-thread-card__name {
  margin: 0;
  font-size: 1.1rem;
  font-weight: 600;
}

.manager-thread-card__login {
  margin: 0.15rem 0 0;
  color: var(--color-muted);
  font-size: 0.92rem;
}

.manager-thread-card__unread {
  min-width: 38px;
  height: 38px;
  border-radius: 50%;
  background: rgba(244, 67, 54, 0.15);
  color: #b71c1c;
  font-weight: 700;
  display: inline-flex;
  align-items: center;
  justify-content: center;
}

.manager-thread-card__meta {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  font-size: 0.85rem;
  color: var(--color-muted);
}

.manager-thread-card__courses {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-wrap: wrap;
  gap: 0.35rem;
}

.manager-thread-card__course {
  border-radius: 999px;
  padding: 0.2rem 0.75rem;
  background: rgba(67, 97, 238, 0.12);
  color: var(--color-text);
  font-weight: 600;
  font-size: 0.82rem;
}

.manager-thread-card__course--basic {
  background: rgba(46, 125, 50, 0.15);
  color: #1e7d32;
}

.manager-thread-card__preview {
  margin: 0;
  color: var(--color-text);
  line-height: 1.5;
  font-size: 0.95rem;
}

.manager-thread-card__footer {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 0.75rem;
  font-size: 0.85rem;
  color: var(--color-muted);
}

.manager-empty-card {
  background: var(--color-surface);
  border-radius: 18px;
  border: 1px dashed rgba(67, 97, 238, 0.4);
  padding: 2rem;
  text-align: center;
  color: var(--color-muted);
  box-shadow: 0 14px 30px rgba(15, 23, 42, 0.08);
}

.manager-thread {
  padding: 3rem 0 4rem;
}

.manager-thread__header {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 1rem;
  margin-bottom: 1.25rem;
}

.manager-thread__eyebrow {
  margin: 0 0 0.35rem;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  font-size: 0.78rem;
  color: var(--color-muted);
}

.manager-thread__header-actions {
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.manager-thread__courses {
  list-style: none;
  margin: 0 0 1.5rem;
  padding: 0;
  display: flex;
  flex-wrap: wrap;
  gap: 0.4rem;
}

.manager-thread__course {
  border-radius: 999px;
  background: rgba(67, 97, 238, 0.12);
  padding: 0.25rem 0.85rem;
  font-weight: 600;
  font-size: 0.85rem;
  color: var(--color-text);
}

.manager-thread__course--basic {
  background: rgba(46, 125, 50, 0.15);
  color: #1e7d32;
}

.manager-thread__messages {
  display: flex;
  flex-direction: column;
  gap: 1rem;
  height: 100%;
  overflow-y: auto;
  padding-right: 0.5rem;
  min-height: 100%;
}

.manager-thread__panel {
  background: var(--color-surface);
  border-radius: var(--radius-lg);
  border: 1px solid rgba(67, 97, 238, 0.12);
  padding: 1.5rem;
  box-shadow: 0 18px 34px rgba(15, 23, 42, 0.08);
  display: flex;
  flex-direction: column;
  gap: 1rem;
  height: calc(100vh - 260px);
  min-height: 420px;
}

.manager-thread__messages-wrap {
  flex: 1;
  border: 1px solid rgba(67, 97, 238, 0.15);
  border-radius: 16px;
  background: rgba(67, 97, 238, 0.03);
  padding: 1rem;
  overflow-y: auto;
  overflow-x: hidden;
  min-height: 300px;
}

.manager-thread__messages-wrap .manager-empty-card {
  margin: 0;
}

.manager-message {
  border-radius: 14px;
  padding: 1rem 1.2rem;
  border: 1px solid rgba(67, 97, 238, 0.08);
  background: var(--color-surface);
  box-shadow: 0 12px 24px rgba(15, 23, 42, 0.05);
}

.manager-message--visitor {
  border-color: rgba(67, 97, 238, 0.15);
}

.manager-message--manager {
  border-color: rgba(46, 125, 50, 0.25);
  background: rgba(46, 125, 50, 0.07);
}

.manager-message--tutor {
  border-color: rgba(251, 140, 0, 0.3);
  background: rgba(251, 140, 0, 0.08);
}

.manager-message__header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 0.75rem;
  font-size: 0.85rem;
  color: var(--color-muted);
  margin-bottom: 0.6rem;
}

.manager-message__body {
  margin: 0;
  line-height: 1.5;
}

.manager-thread__form {
  display: flex;
  flex-direction: column;
  gap: 0.65rem;
  margin: 0;
}

.manager-thread__composer {
  position: relative;
  background: #fff;
  border: 1px solid var(--color-border);
  border-radius: 22px;
  padding: 0.75rem 3.25rem 0.75rem 1.25rem;
  display: flex;
  align-items: center;
  transition: border-color var(--transition), box-shadow var(--transition);
}

.manager-thread__composer:focus-within {
  border-color: var(--color-primary);
  box-shadow: 0 0 0 3px rgba(67, 97, 238, 0.16);
}

.manager-thread__composer textarea {
  border: none;
  width: 100%;
  resize: none;
  font-size: 1rem;
  line-height: 1.4;
  max-height: 180px;
  min-height: 26px;
  overflow: hidden;
}

.manager-thread__composer textarea:focus {
  outline: none;
}

.manager-thread__send {
  position: absolute;
  right: 0.6rem;
  top: 50%;
  transform: translateY(-50%);
  width: 40px;
  height: 40px;
  border-radius: 50%;
  border: none;
  background: linear-gradient(135deg, #6f5dff, #8b6dff);
  color: #fff;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  box-shadow: 0 12px 24px rgba(111, 93, 255, 0.25);
  transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.manager-thread__send svg {
  width: 18px;
  height: 18px;
}

.manager-thread__send:hover {
  transform: translateY(calc(-50% - 2px));
  box-shadow: 0 16px 30px rgba(111, 93, 255, 0.3);
}

.manager-thread__form-footer {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 0.75rem;
}

@media (max-width: 720px) {
  .manager-messages__header {
    flex-direction: column;
  }

  .manager-messages__meta {
    align-items: flex-start;
  }

  .manager-thread__header {
    flex-direction: column;
    align-items: flex-start;
    gap: 0.5rem;
  }

  .manager-thread__form-footer {
    flex-direction: column;
    align-items: stretch;
  }

  .manager-thread__form-footer .btn {
    width: 100%;
  }

  .manager-thread__panel {
    height: auto;
  }
}

@media (max-width: 640px) {
  .manager-dashboard__card {
    padding: 1.5rem;
  }

  .manager-dashboard__header form {
    width: 100%;
    display: flex;
    justify-content: flex-start;
  }

  .manager-dashboard__cta .btn {
    width: 100%;
  }
}

.admin-dashboard-meta {
  font-size: 0.95rem;
  color: var(--color-muted);
}

.admin-action-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 1rem;
}

.admin-action {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 1.2rem 1rem;
  border-radius: 14px;
  border: 1px dashed rgba(67, 97, 238, 0.25);
  background: rgba(67, 97, 238, 0.05);
  font-weight: 600;
  font-size: 1rem;
  color: var(--color-primary);
  cursor: pointer;
  transition: background var(--transition), border-color var(--transition);
}

.admin-action[disabled] {
  opacity: 0.6;
  cursor: not-allowed;
  pointer-events: none;
}

.admin-action:hover {
  border-color: var(--color-primary);
  background: rgba(67, 97, 238, 0.08);
}

.admin-action:active {
  transform: translateY(1px);
}

.admin-action-primary {
  border-style: solid;
  background: linear-gradient(135deg, var(--color-primary), var(--color-accent));
  color: #ffffff;
}

.admin-upload-form {
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
  margin: 0;
  width: 100%;
}

.admin-upload-form input[type='file'] {
  display: none;
}

.admin-action-upload {
  width: 100%;
}

.admin-action-form {
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
  align-items: stretch;
}

.admin-action-form h3 {
  margin: 0;
  font-size: 1rem;
  color: var(--color-text);
}

.admin-inline-form {
  display: flex;
  gap: 0.5rem;
}

.admin-input {
  flex: 1;
  border: 1px solid var(--color-border);
  border-radius: 999px;
  padding: 0.45rem 0.9rem;
}

.btn-danger {
  background: #e53935;
  border-color: #e53935;
  color: #ffffff;
}

.btn-danger:disabled {
  opacity: 0.5;
}

.admin-upload-help {
  font-size: 0.85rem;
  color: var(--color-muted);
  margin: 0;
}
.admin-upload-file {
  font-size: 0.9rem;
  color: var(--color-muted);
  margin: 0;
}
.admin-upload-submit {
  margin-top: 0.4rem;
}

.admin-upload-summary {
  margin-top: 2.5rem;
  background: var(--color-surface);
  border-radius: var(--radius-lg);
  padding: 1.75rem;
  border: 1px solid rgba(67, 97, 238, 0.12);
  box-shadow: 0 12px 24px rgba(15, 23, 42, 0.08);
}

.admin-upload-summary h2 {
  margin-top: 0;
  margin-bottom: 0.75rem;
}

.admin-upload-summary p {
  margin-top: 0;
  color: var(--color-muted);
}

.admin-upload-list {
  margin: 1rem 0 0;
  padding-left: 1.25rem;
  display: grid;
  gap: 1rem;
}

.admin-upload-question {
  font-weight: 600;
  margin: 0 0 0.5rem;
}

.admin-upload-answers {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 0.35rem;
}

.admin-upload-answers li {
  font-size: 0.95rem;
}

.admin-upload-answers .answer-correct {
  color: #2e7d32;
}

.admin-upload-answers .answer-wrong {
  color: var(--color-muted);
}

.alert {
  border-radius: 12px;
  padding: 1rem 1.25rem;
  margin: 1.5rem 0;
  font-weight: 500;
}

.alert-error {
  background: rgba(244, 67, 54, 0.08);
  color: #c62828;
  border: 1px solid rgba(244, 67, 54, 0.25);
}

.alert-success {
  background: rgba(52, 168, 83, 0.12);
  color: #2e7d32;
  border: 1px solid rgba(52, 168, 83, 0.28);
}

.alert-warning {
  background: rgba(255, 193, 7, 0.15);
  color: #8a6d3b;
  border: 1px solid rgba(255, 193, 7, 0.3);
}

.course-selection {
  padding: 3rem 0 4rem;
}

.course-selection-header h1 {
  margin-bottom: 0.5rem;
}

.course-selection-header p {
  color: var(--color-muted);
  margin-top: 0;
}

.course-empty {
  margin-top: 2.5rem;
  display: flex;
  justify-content: center;
}

.course-empty-card {
  background: var(--color-surface);
  border-radius: var(--radius-lg);
  border: 1px dashed rgba(67, 97, 238, 0.4);
  padding: 2.5rem 2rem;
  max-width: 460px;
  text-align: center;
  color: var(--color-muted);
  box-shadow: 0 12px 28px rgba(67, 97, 238, 0.08);
}

.course-grid {
  margin-top: 2.5rem;
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 1.8rem;
}

.course-card {
  background: var(--color-surface);
  border-radius: var(--radius-lg);
  padding: 1.85rem;
  border: 1px solid rgba(67, 97, 238, 0.08);
  box-shadow: 0 12px 26px rgba(15, 23, 42, 0.08);
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
  transition: transform var(--transition), box-shadow var(--transition);
}

.course-card:hover {
  transform: translateY(-4px);
  box-shadow: 0 20px 40px rgba(15, 23, 42, 0.12);
}

.course-card-progress-wrapper {
  gap: 1.25rem;
}

.course-card-main {
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

.course-card-info {
  display: flex;
  flex-direction: column;
  gap: 0.6rem;
}

.course-card-progress {
  width: 100%;
  display: inline-flex;
  align-items: center;
  gap: 0.85rem;
  padding: 0.85rem 1.1rem;
  border-radius: 20px;
  background: rgba(14, 19, 41, 0.06);
  justify-content: flex-start;
}

.course-card-progress-text {
  display: flex;
  flex-direction: column;
  gap: 0.15rem;
  font-size: 0.92rem;
  color: var(--color-text);
}

.course-card-progress-text strong {
  font-size: 0.95rem;
}

.course-card-progress-text span {
  color: var(--color-muted);
  font-size: 0.85rem;
}

.course-card-progress-empty {
  display: flex;
  flex-direction: column;
  gap: 0.15rem;
  font-size: 0.9rem;
  color: var(--color-muted);
}

.course-card-groups {
  display: flex;
  flex-direction: column;
  gap: 0.35rem;
  margin-top: 0.4rem;
}

.course-card-group-row {
  display: flex;
  flex-wrap: wrap;
  gap: 0.4rem;
  align-items: center;
}

.course-card-group-empty {
  margin: 0;
}

.course-type {
  display: inline-flex;
  align-items: center;
  font-size: 0.8rem;
  font-weight: 600;
  padding: 0.3rem 0.75rem;
  border-radius: 999px;
  letter-spacing: 0.01em;
  text-transform: uppercase;
}

.course-type-main {
  background: rgba(52, 168, 83, 0.12);
  color: #2e7d32;
}

.course-type-demo {
  background: rgba(251, 140, 0, 0.13);
  color: #e65100;
}

.course-category,
.course-description,
.course-role {
  margin: 0;
  color: var(--color-muted);
  line-height: 1.5;
}

.course-category {
  font-weight: 600;
  color: var(--color-primary);
}

.course-role {
  margin-top: auto;
  font-size: 0.95rem;
}

.course-overview {
  padding: 3rem 0 4rem;
  display: flex;
  flex-direction: column;
  gap: 2.5rem;
}

.course-overview-header h1 {
  margin-bottom: 0.5rem;
}

.course-overview-badges {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
  margin-bottom: 1rem;
}

.course-category-badge {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  padding: 0.35rem 0.8rem;
  border-radius: 999px;
  background: rgba(67, 97, 238, 0.12);
  color: var(--color-primary);
  font-weight: 600;
  font-size: 0.85rem;
}

.course-membership {
  margin-top: 0;
  color: var(--color-muted);
}

.course-overview-actions {
  margin-top: 1rem;
}

.course-group-strip {
  margin-top: 1rem;
}

.course-group-badges {
  display: flex;
  flex-direction: column;
  gap: 0.6rem;
}

.course-group-item {
  display: flex;
  flex-direction: column;
  gap: 0.45rem;
  align-items: flex-start;
}

.course-group-entry {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  flex-wrap: wrap;
}

.course-group-label-inline {
  font-weight: 600;
  color: var(--color-text);
  margin-right: 0.25rem;
}

.course-group-badge {
  background: rgba(67, 97, 238, 0.12);
  color: var(--color-primary);
  padding: 0.2rem 0.75rem;
  border-radius: 999px;
  font-weight: 600;
  font-size: 0.9rem;
}

.course-group-meta {
  font-size: 0.85rem;
  color: var(--color-muted);
  background: rgba(67, 97, 238, 0.08);
  padding: 0.2rem 0.75rem;
  border-radius: 999px;
  font-weight: 600;
}

.course-group-actions {
  display: flex;
  align-items: center;
  gap: 0.4rem;
  flex-wrap: wrap;
}

.course-group-actions .btn {
  font-size: 0.85rem;
  padding: 0.35rem 0.75rem;
}

.course-group-actions .btn[disabled] {
  opacity: 0.5;
  cursor: not-allowed;
}

.course-group-progress {
  display: inline-flex;
  align-items: center;
  gap: 0.75rem;
  padding: 0.6rem 0.9rem;
  border-radius: 999px;
  background: rgba(14, 19, 41, 0.06);
  align-self: flex-start;
  margin-bottom: 0;
}

.course-group-progress-ring,
.course-card-progress-ring {
  width: 60px;
  height: 60px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  position: relative;
  font-weight: 700;
  color: var(--progress-text-color, var(--color-primary));
  background:
    conic-gradient(
      var(--progress-color, var(--color-primary)) var(--progress-value, 0%),
      rgba(14, 19, 41, 0.15) 0
    );
}

.course-card-progress-ring {
  width: 78px;
  height: 78px;
}

.course-group-progress-ring::after,
.course-card-progress-ring::after {
  content: '';
  position: absolute;
  inset: 6px;
  background: #fff;
  border-radius: 50%;
}

.course-group-progress-ring span,
.course-card-progress-ring span {
  position: relative;
  font-size: 0.95rem;
  z-index: 1;
}

.course-card-progress-ring span {
  font-size: 1.05rem;
}

.course-group-progress-ring.progress-low,
.course-card-progress-ring.progress-low {
  --progress-color: #e15554;
  --progress-text-color: #c13b2b;
}

.course-group-progress-ring.progress-mid,
.course-card-progress-ring.progress-mid {
  --progress-color: #f3ad26;
  --progress-text-color: #b1770f;
}

.course-group-progress-ring.progress-good,
.course-card-progress-ring.progress-good {
  --progress-color: #2fb17d;
  --progress-text-color: #1d7251;
}

.course-group-progress-text {
  display: flex;
  flex-direction: column;
  gap: 0.2rem;
}

.course-group-progress-text p {
  margin: 0;
  font-weight: 600;
  color: var(--color-text);
  font-size: 0.9rem;
}

.course-group-progress-text small {
  color: var(--color-muted);
  font-size: 0.8rem;
}

.group-samples {
  padding: 2.5rem 0 3rem;
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

.sample-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 1.25rem;
}

.sample-card {
  background: #ffffff;
  border-radius: 1rem;
  border: 1px solid rgba(32, 33, 36, 0.08);
  box-shadow: 0 12px 24px rgba(15, 23, 42, 0.08);
  padding: 1rem;
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}

.sample-preview {
  border-radius: 0.75rem;
  overflow: hidden;
  border: 1px solid rgba(32, 33, 36, 0.08);
  background: #f8fafc;
  display: flex;
  justify-content: center;
  align-items: center;
  min-height: 180px;
}

.sample-preview img {
  max-width: 100%;
  height: auto;
  display: block;
}

.sample-actions {
  display: flex;
  justify-content: flex-start;
}

.course-overview-description {
  background: var(--color-surface);
  border-radius: var(--radius-lg);
  border: 1px solid rgba(67, 97, 238, 0.08);
  padding: 2rem;
  box-shadow: 0 12px 28px rgba(15, 23, 42, 0.08);
}

.course-overview-description p {
  margin: 0;
  line-height: 1.6;
}

.course-demo-note {
  margin-top: 1.25rem;
  padding: 1.1rem 1.3rem;
  border-radius: 14px;
  background: linear-gradient(135deg, rgba(255, 198, 120, 0.18), rgba(255, 243, 224, 0.85));
  border: 1px solid rgba(255, 176, 84, 0.4);
  color: #b55604;
  box-shadow: 0 10px 28px rgba(255, 176, 84, 0.25);
  font-size: 0.98rem;
  line-height: 1.5;
}

.course-demo-note strong {
  display: inline-block;
  margin-bottom: 0.35rem;
  text-transform: uppercase;
  letter-spacing: 0.04em;
  font-size: 0.84rem;
  color: #d45b02;
}

.course-demo-docs-btn {
  margin-left: 0.75rem;
  padding: 0.4rem 1.1rem;
  border-radius: 999px;
  border: none;
  background: linear-gradient(135deg, #ff9f43, #ff6f00);
  color: #fff;
  font-weight: 600;
  font-size: 0.9rem;
  cursor: pointer;
  box-shadow: 0 10px 20px rgba(255, 159, 67, 0.35);
  transition: transform var(--transition), box-shadow var(--transition);
}

.course-demo-docs-btn:hover {
  transform: translateY(-1px);
  box-shadow: 0 12px 24px rgba(255, 159, 67, 0.4);
}

.course-demo-modal {
  position: fixed;
  inset: 0;
  z-index: 1050;
}

.course-demo-modal[hidden] {
  display: none;
}

.course-demo-modal__backdrop {
  position: absolute;
  inset: 0;
  background: rgba(15, 23, 42, 0.4);
}

.course-demo-modal__dialog {
  position: relative;
  max-width: 520px;
  margin: 10vh auto;
  background: #fff;
  border-radius: 20px;
  padding: 2rem;
  box-shadow: 0 30px 80px rgba(15, 23, 42, 0.25);
}

.course-demo-modal__dialog h3 {
  margin-top: 0;
  margin-bottom: 0.8rem;
  color: #1f2555;
}

.course-demo-modal__dialog p {
  margin: 0;
  line-height: 1.5;
  color: #4a4e69;
}

.course-demo-modal__close {
  position: absolute;
  top: 1rem;
  right: 1rem;
  border: none;
  border-radius: 50%;
  width: 36px;
  height: 36px;
  background: rgba(31, 37, 85, 0.08);
  color: #1f2555;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
}

.course-demo-modal__close svg {
  width: 18px;
  height: 18px;
}

.course-demo-modal__intro {
  margin: 0 0 1rem 0;
  color: #4a516b;
  line-height: 1.5;
}

.demo-dropzone {
  border: 2px dashed rgba(67, 97, 238, 0.4);
  border-radius: 18px;
  padding: 1.25rem;
  background: rgba(248, 249, 255, 0.85);
  margin-bottom: 1rem;
  transition: border-color var(--transition), background var(--transition);
}

.demo-dropzone--active {
  border-color: rgba(67, 97, 238, 0.8);
  background: rgba(223, 229, 255, 0.9);
}

.demo-dropzone__inner {
  text-align: center;
  margin-bottom: 0.8rem;
}

.demo-dropzone__icon {
  font-size: 2rem;
  display: block;
  margin-bottom: 0.4rem;
}

.demo-dropzone__browse {
  border: none;
  background: none;
  color: var(--color-primary);
  font-weight: 600;
  cursor: pointer;
  text-decoration: underline;
}

.demo-dropzone__list {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
}

.demo-dropzone__placeholder {
  width: 100%;
  text-align: center;
  margin: 0;
  color: var(--color-muted);
}

.demo-preview {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.5rem 0.75rem;
  border-radius: 12px;
  background: #fff;
  border: 1px solid rgba(67, 97, 238, 0.2);
  min-width: 200px;
}

.demo-preview-thumb {
  width: 42px;
  height: 42px;
  border-radius: 10px;
  background: rgba(67, 97, 238, 0.08);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.2rem;
  color: #435fef;
  overflow: hidden;
}

.demo-preview-thumb-img {
  width: 100%;
  height: 100%;
  display: block;
  background-size: cover;
  background-position: center;
}

.demo-preview-info {
  flex: 1;
  min-width: 0;
}

.demo-preview-info strong {
  display: block;
  font-size: 0.9rem;
}

.demo-preview-info small {
  color: var(--color-muted);
}

.demo-preview-remove {
  border: none;
  background: rgba(15, 23, 42, 0.08);
  width: 28px;
  height: 28px;
  border-radius: 50%;
  cursor: pointer;
  font-size: 1rem;
  line-height: 1;
}

.demo-checkboxes {
  display: flex;
  flex-direction: column;
  gap: 0.6rem;
  margin: 0.25rem 0 0.35rem 0;
}

.demo-checkbox {
  display: flex;
  gap: 0.5rem;
  font-size: 0.95rem;
  color: #2a2f45;
}

.demo-checkbox input {
  margin-top: 0.25rem;
}

.demo-checkbox-note {
  margin: 0 0 0.05rem 0;
  font-size: 0.93rem;
  color: #2a2f45;
  line-height: 1.45;
  font-style: italic;
  font-weight: 600;
}

.demo-comment {
  display: flex;
  flex-direction: column;
  gap: 0.35rem;
  margin-top: 0;
  margin-bottom: 1rem;
  color: #2a2f45;
}

.demo-comment textarea {
  width: 100%;
  border: 1px solid var(--color-border);
  border-radius: 14px;
  padding: 0.75rem 1rem;
  resize: none;
  min-height: 44px;
  max-height: 200px;
}

.demo-comment textarea:focus {
  outline: none;
  border-color: var(--color-primary);
  box-shadow: 0 0 0 3px rgba(67, 97, 238, 0.16);
}

.demo-submit {
  width: 100%;
  justify-content: center;
}

.demo-submit:disabled {
  opacity: 0.6;
  cursor: not-allowed;
  box-shadow: none;
}
body.modal-open {
  overflow: hidden;
}

.course-demo-docs {
  margin-top: 0.75rem;
  border-radius: 12px;
  border: 1px dashed rgba(255, 176, 84, 0.5);
  background: rgba(255, 247, 237, 0.9);
  color: #854c00;
  padding: 0.9rem 1rem;
}

.course-demo-docs summary {
  cursor: pointer;
  font-weight: 600;
  color: #b55604;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 0.35rem;
  outline: none;
}

.course-demo-docs summary span:last-child {
  font-size: 1.2rem;
  transition: transform 0.2s ease;
}

.course-demo-docs[open] summary span:last-child {
  transform: rotate(90deg);
}

.course-demo-docs summary::marker {
  color: #b55604;
}

.course-demo-docs[open] summary {
  margin-bottom: 0.5rem;
}

.course-demo-docs ol {
  margin: 0;
  padding-left: 1.25rem;
  display: flex;
  flex-direction: column;
  gap: 0.35rem;
}

.course-demo-docs li {
  line-height: 1.5;
}

.course-demo-docs-footer {
  margin-top: 0.9rem;
  display: flex;
  justify-content: flex-start;
}

.course-messages {
  padding: 2rem 0 3rem;
  display: flex;
  flex-direction: column;
  gap: 1.5rem;
}

.course-messages-header .back-link {
  margin-bottom: 0.5rem;
}

.course-messages-header h1 {
  margin: 0 0 0.5rem;
}

.message-thread {
  margin-top: 0.5rem;
}

.message-form-wrapper {
  margin-top: 1rem;
}

.message-form {
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}

.message-label {
  font-weight: 600;
  color: rgba(21, 32, 48, 0.85);
}

.message-form textarea {
  width: 100%;
  min-height: 160px;
  border-radius: 12px;
  border: 1px solid rgba(21, 32, 48, 0.2);
  padding: 1rem;
  font-size: 1rem;
  resize: vertical;
}

.message-form textarea:focus {
  border-color: rgba(63, 130, 244, 0.7);
  outline: none;
  box-shadow: 0 0 0 3px rgba(63, 130, 244, 0.2);
}

.message-form-footer {
  margin-top: 0.75rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 1rem;
}

.course-group-switch-btn {
  margin: 1.5rem 0 1.25rem;
}

.group-switch-modal .sample-modal-dialog {
  max-width: 560px;
  padding: 1.5rem;
}

.group-switch-header {
  margin-bottom: 1rem;
}

.group-switch-title {
  margin: 0;
  font-weight: 600;
  font-size: 1.1rem;
}

.group-switch-subtitle {
  margin: 0.35rem 0 0;
  color: rgba(21, 32, 48, 0.7);
  font-size: 0.9rem;
}

.group-switch-list {
  display: flex;
  flex-direction: column;
  gap: 0.65rem;
  margin: 0 0 0.75rem;
  max-height: 360px;
  overflow-y: auto;
  padding-right: 0.4rem;
}

.group-switch-item {
  border: 1px solid rgba(91, 118, 255, 0.2);
  border-radius: 12px;
  padding: 0.85rem 1rem;
  background: #f5f7ff;
  box-shadow: 0 4px 20px rgba(91, 118, 255, 0.12);
}

.group-switch-item.is-current {
  border-color: rgba(91, 118, 255, 0.6);
  background: linear-gradient(135deg, rgba(91, 118, 255, 0.12), rgba(255, 255, 255, 0.8));
}

.group-switch-name {
  display: flex;
  align-items: center;
  gap: 0.4rem;
  margin-bottom: 0.4rem;
}

.group-switch-current {
  font-size: 0.78rem;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: #5b76ff;
}

.group-switch-meta {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
  font-size: 0.9rem;
  color: rgba(21, 32, 48, 0.75);
}

.group-switch-price {
  margin: 0.4rem 0;
  display: flex;
  flex-wrap: wrap;
  gap: 0.35rem;
  align-items: center;
  font-size: 0.9rem;
  color: rgba(21, 32, 48, 0.85);
}

.group-switch-price-value {
  display: inline-flex;
  align-items: center;
  gap: 0.45rem;
  flex-wrap: wrap;
}

.group-switch-price-note {
  font-size: 0.78rem;
  color: rgba(21, 32, 48, 0.6);
}

.group-switch-price-value strong {
  font-size: 1rem;
}

.group-switch-price-diff {
  font-size: 0.85rem;
  font-weight: 700;
}

.group-switch-price-diff.positive {
  color: #059669;
}

.group-switch-price-diff.negative {
  color: #dc2626;
}

.group-switch-extra {
  display: flex;
  flex-direction: column;
  gap: 0.2rem;
  margin-top: 0.4rem;
  font-size: 0.88rem;
  color: rgba(21, 32, 48, 0.78);
}

.group-switch-pill {
  display: inline-flex;
  align-items: center;
  padding: 0.2rem 0.55rem;
  border-radius: 999px;
  background: rgba(91, 118, 255, 0.1);
  border: 1px solid rgba(91, 118, 255, 0.25);
  color: #3841a5;
  font-size: 0.82rem;
}

.group-switch-actions {
  margin-top: 0.6rem;
}

.group-switch-actions .btn {
  width: 100%;
}

.demo-price-card {
  margin-top: 1.5rem;
  display: flex;
  flex-direction: row;
  gap: 1rem;
}

.demo-price-column {
  flex: 1 1 0;
  border-radius: 18px;
  padding: 1.25rem 1.5rem;
  background: linear-gradient(135deg, rgba(80, 133, 255, 0.12), rgba(255, 255, 255, 0.9));
  border: 1px solid rgba(80, 133, 255, 0.25);
  box-shadow: 0 20px 40px rgba(56, 91, 255, 0.18);
  min-width: 260px;
}

.demo-price-column + .demo-price-column {
  background: linear-gradient(135deg, rgba(80, 133, 255, 0.12), rgba(255, 255, 255, 0.9));
}

.demo-price-column h3,
.demo-price-column h4 {
  margin: 0 0 0.35rem;
  color: #1d2a6b;
}

.demo-price-note {
  margin: 0 0 0.75rem;
  color: rgba(21, 32, 48, 0.75);
}

.demo-price-highlight {
  border-radius: 14px;
  padding: 0.9rem 1rem;
  background: rgba(91, 118, 255, 0.12);
  border: 1px solid rgba(91, 118, 255, 0.3);
}

.demo-price-label {
  margin: 0;
  font-size: 0.85rem;
  color: rgba(21, 32, 48, 0.65);
}

.demo-price-value {
  margin: 0.2rem 0 0;
  font-size: 1.3rem;
  font-weight: 700;
  color: #2633a6;
}

.demo-price-saving {
  margin: 0.25rem 0 0;
  font-size: 0.92rem;
  color: #057a55;
  font-weight: 600;
}

.group-switch-hint {
  margin: 0.5rem 0 0;
  font-size: 0.85rem;
  color: rgba(21, 32, 48, 0.6);
}

.course-sections {
  display: flex;
  flex-direction: column;
  gap: 1.75rem;
}

.course-sections h2 {
  margin: 0;
}

.section-list {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
  gap: 1.5rem;
}

.section-card {
  background: var(--color-surface);
  border-radius: var(--radius-lg);
  border: 1px solid rgba(67, 97, 238, 0.1);
  box-shadow: 0 12px 28px rgba(15, 23, 42, 0.08);
  padding: 1.4rem 1.5rem;
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

.section-position {
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--color-primary);
  letter-spacing: 0.02em;
}

.section-type-badge {
  align-self: flex-start;
  padding: 0.25rem 0.65rem;
  border-radius: 999px;
  background: rgba(76, 201, 240, 0.14);
  color: #007ea7;
  font-weight: 600;
  font-size: 0.75rem;
  letter-spacing: 0.02em;
  text-transform: uppercase;
}

.section-card h3 {
  margin: 0.35rem 0 0.1rem;
  line-height: 1.3;
  min-height: 5.2rem;
}

.section-card p {
  margin: 0;
}

.section-resources {
  margin-top: 0.85rem;
  display: grid;
  gap: 1rem;
}

.resource-group h4 {
  margin: 0 0 0.35rem;
  font-size: 0.95rem;
  text-transform: uppercase;
  letter-spacing: 0.04em;
  color: var(--color-muted);
}

.resource-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 0.5rem;
}

.resource-list li {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 1rem;
  padding: 0.65rem 0.75rem;
  border-radius: 12px;
  background: rgba(67, 97, 238, 0.05);
}

.resource-list-compact li {
  background: rgba(67, 97, 238, 0.03);
}

.resource-list.resource-list-tests .test-item {
  border-radius: 12px;
  padding: 0.85rem 1rem;
  border: 1px solid rgba(32, 33, 36, 0.08);
  background: #ffffff;
  box-shadow: 0 12px 24px rgba(15, 23, 42, 0.08);
}

.resource-list.resource-list-tests .test-item-neutral {
  background: rgba(67, 97, 238, 0.04);
}

.resource-list.resource-list-tests .test-item-pass {
  background: rgba(46, 125, 50, 0.08);
  border-color: rgba(46, 125, 50, 0.2);
}

.resource-list.resource-list-tests .test-item-fail {
  background: rgba(220, 85, 63, 0.08);
  border-color: rgba(220, 85, 63, 0.2);
}

.test-status-pill {
  display: inline-flex;
  align-items: center;
  gap: 0.25rem;
  padding: 0.15rem 0.6rem;
  border-radius: 999px;
  font-size: 0.8rem;
  font-weight: 600;
}

.test-status-pill.pill-pass {
  background: rgba(46, 125, 50, 0.18);
  color: #1b5e20;
}

.test-status-pill.pill-fail {
  background: rgba(220, 85, 63, 0.18);
  color: #7c1d16;
}

.test-status-pill.pill-neutral {
  background: rgba(67, 97, 238, 0.18);
  color: var(--color-primary);
}

.resource-info {
  display: flex;
  flex-direction: column;
  gap: 0.2rem;
}

.resource-name {
  font-weight: 600;
}

.resource-meta {
  font-size: 0.85rem;
  color: var(--color-muted);
}

.progress-red {
  color: #c62828;
  font-weight: 600;
}

.progress-yellow {
  color: #f9a825;
  font-weight: 600;
}

.progress-green {
  color: #2e7d32;
  font-weight: 600;
}

.resource-actions {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  flex-wrap: wrap;
}

.resource-status {
  font-size: 0.85rem;
  color: var(--color-muted);
}

.resource-status-warning {
  color: #b45309;
  font-weight: 600;
}

.btn-link {
  color: var(--color-primary);
  font-weight: 600;
  font-size: 0.9rem;
  text-decoration: none;
  padding: 0.15rem 0;
  border-bottom: 1px solid transparent;
  transition: border-color var(--transition), color var(--transition);
}

.btn-link:hover {
  color: var(--color-primary-dark);
  border-color: currentColor;
}

.pdf-viewer-body {
  margin: 0;
  background: var(--color-bg);
  font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
}

.file-viewer {
  padding: 2.5rem 0 3rem;
  display: flex;
  flex-direction: column;
  gap: 1.5rem;
}

.file-viewer-header {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 1rem 1.5rem;
}

.file-viewer-header h1 {
  flex: 1 1 auto;
  margin: 0;
  font-size: 1.5rem;
}

.file-viewer-left {
  display: flex;
  align-items: center;
  gap: 1rem;
  flex: 1 1 320px;
  min-width: 280px;
}

.file-viewer-toolbar {
  display: flex;
  flex: 1 1 320px;
  align-items: center;
  justify-content: flex-end;
  gap: 0.75rem 1rem;
  flex-wrap: wrap;
}

.file-viewer-actions {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  flex-wrap: wrap;
}

.viewer-chip {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-width: 70px;
  padding: 0.45rem 0.9rem;
  border-radius: 999px;
  border: 1px solid var(--color-border);
  background: #ffffff;
  font-weight: 600;
  font-size: 0.95rem;
  color: var(--color-text);
}

.viewer-scale,
.viewer-page {
  color: var(--color-primary);
}

.file-viewer-return {
  white-space: nowrap;
}

.pdf-viewer-frame-wrapper {
  position: relative;
  border-radius: var(--radius-lg);
  box-shadow: 0 20px 40px rgba(15, 23, 42, 0.12);
  overflow: hidden;
  border: 1px solid rgba(67, 97, 238, 0.12);
  background: #ffffff;
  min-height: 70vh;
  height: calc(100vh - 220px);
}

.pdfViewerContainer {
  position: absolute;
  inset: 0;
  overflow: auto;
  background: #ffffff;
}

#viewer {
  padding: 1rem;
}

.pdf-limit-overlay {
  position: absolute;
  inset: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  background: rgba(15, 23, 42, 0.55);
  z-index: 2;
}

.pdf-limit-overlay[hidden] {
  display: none;
}

.pdf-limit-overlay-card {
  max-width: 420px;
  background: #ffffff;
  border-radius: 20px;
  padding: 1.5rem;
  text-align: center;
  box-shadow: 0 25px 50px rgba(15, 23, 42, 0.3);
  display: flex;
  flex-direction: column;
  gap: 0.6rem;
}

.pdf-limit-overlay-card p {
  margin: 0.75rem 0 1rem;
  color: rgba(21, 32, 48, 0.85);
}

.pdf-limit-overlay-card .pdf-limit-btn {
  align-self: center;
  margin-top: 0.2rem;
}

.pdf-viewer-body,
.pdf-viewer-body * {
  -webkit-user-select: none;
  -ms-user-select: none;
  user-select: none;
}

.pdf-viewer-body .textLayer,
.pdf-viewer-body .textLayer span,
.pdf-viewer-body .textLayer div {
  pointer-events: none !important;
  -webkit-user-select: none !important;
  user-select: none !important;
}

.viewer-scale,
.viewer-page {
  font-weight: 600;
}

.pdf-error {
  padding: 2rem;
  text-align: center;
  color: var(--color-muted);
}

.status-page {
  padding: 6rem 0;
  text-align: center;
}

.status-page h1 {
  font-size: 2.4rem;
  margin-bottom: 1rem;
}

.status-page p {
  color: var(--color-muted);
  margin-bottom: 2rem;
}

.status-caption {
  font-size: 0.9rem;
  color: var(--color-muted);
  margin-bottom: 2rem;
}

.site-footer {
  border-top: 1px solid var(--color-border);
  background: var(--color-surface);
  padding: 0.9rem 0;
  margin-top: 2rem;
}

.footer-content {
  text-align: center;
  color: var(--color-muted);
  font-size: 0.9rem;
}

@media (max-width: 720px) {
  .header-content {
    flex-direction: column;
    align-items: flex-start;
    gap: 1rem;
  }

  .brand {
    font-size: 1rem;
  }

  .hero {
    padding: 4rem 0 3rem;
  }

  .hero-actions {
    width: 100%;
  }

  .hero-actions .btn {
    flex: 1 1 auto;
  }

  .course-grid {
    grid-template-columns: 1fr;
  }

  .course-overview {
    padding: 2.5rem 0 3rem;
  }

  .course-overview-actions {
    width: 100%;
  }

  .course-overview-actions .btn {
    width: 100%;
  }

  .course-empty-card {
    padding: 2rem 1.5rem;
  }

.file-viewer {
  padding: 1.5rem 0 2rem;
}

.file-viewer-header {
  align-items: flex-start;
}

.file-viewer-actions {
  width: 100%;
  flex-wrap: wrap;
  justify-content: flex-start;
}

.file-viewer-left {
  flex-direction: column;
  align-items: flex-start;
  min-width: 100%;
}

.file-viewer-toolbar {
  width: 100%;
  flex-direction: column;
  align-items: flex-start;
}

.file-viewer-return {
  width: 100%;
  text-align: center;
}

.pdf-viewer-frame-wrapper {
  height: calc(100vh - 260px);
}

.site-footer {
  margin-top: 3rem;
}

 .locked-sections-note {
  margin-top: 2rem;
  padding: 1.25rem 1.5rem;
  border-radius: var(--radius-lg);
  border: 1px solid rgba(220, 85, 63, 0.3);
  background: rgba(220, 85, 63, 0.08);
}

.locked-sections-note ul {
  margin: 0.75rem 0 0;
  padding-left: 1.2rem;
  color: var(--color-text);
  line-height: 1.5;
}

/* Course groups and access */
.course-group-strip {
  margin-top: 1rem;
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
  align-items: center;
}

.course-group-badges {
  display: flex;
  flex-wrap: wrap;
  gap: 0.4rem;
}

.course-group-badge {
  background: rgba(67, 97, 238, 0.12);
  color: var(--color-primary);
  padding: 0.2rem 0.75rem;
  border-radius: 999px;
  font-weight: 600;
  font-size: 0.9rem;
}

.section-card-locked {
  border-color: rgba(220, 85, 63, 0.35);
  box-shadow: inset 0 0 0 1px rgba(220, 85, 63, 0.12);
}

.section-locked-hint {
  margin: 0.75rem 0;
  background: rgba(220, 85, 63, 0.12);
  color: #7c1d16;
  border-radius: 0.8rem;
  padding: 0.65rem 0.85rem;
  font-size: 0.9rem;
}

.resource-group-disabled {
  opacity: 0.6;
}
}
.test-attempt,
.test-result {
  padding: 2rem 0;
}

.test-attempt-header,
.test-result-header {
  margin-bottom: 1.5rem;
}

.back-link a {
  color: var(--color-muted);
  font-size: 0.9rem;
}

.test-form,
.test-result-details {
  display: flex;
  flex-direction: column;
  gap: 1.5rem;
}

.test-question,
.test-result-question {
  background: var(--color-surface);
  border-radius: var(--radius-lg);
  padding: 1.25rem;
  border: 1px solid rgba(32, 33, 36, 0.08);
}

.test-attempt-toolbar {
  position: sticky;
  top: 64px;
  z-index: 10;
  background: var(--color-bg);
  border-bottom: 1px solid rgba(32, 33, 36, 0.08);
  padding: 0.85rem 0;
}

.test-attempt-toolbar-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
}

.test-attempt-toolbar-info {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-size: 0.95rem;
}

.test-attempt-toolbar-info strong {
  font-size: 1rem;
  color: var(--color-text);
}

.test-attempt-footer {
  position: sticky;
  bottom: 24px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  margin-top: 2rem;
  background: var(--color-surface);
  border: 1px solid rgba(32, 33, 36, 0.08);
  border-radius: var(--radius-lg);
  box-shadow: 0 20px 40px rgba(15, 23, 42, 0.12);
  padding: 0.75rem 1.5rem;
}

.footer-progress {
  font-weight: 600;
  color: var(--color-text);
}

.footer-progress-count {
  font-size: 1.1rem;
  color: var(--color-primary);
  margin: 0 0.25rem;
}

.test-submit-btn {
  min-width: 210px;
  text-align: center;
}

@media (max-width: 720px) {
  .test-attempt-toolbar-inner {
    flex-direction: column;
    align-items: flex-start;
  }

  .test-attempt-footer {
    flex-direction: column;
    align-items: stretch;
  }

  .test-submit-btn {
    width: 100%;
  }
}

.test-question header,
.test-result-question header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 0.75rem;
  font-size: 0.95rem;
  color: var(--color-muted);
}

.question-text {
  font-size: 1rem;
  margin: 0 0 0.75rem;
  font-weight: 600;
}

.answer-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 0.5rem;
}

.answer-option {
  display: flex;
  align-items: center;
  gap: 0.4rem;
  font-size: 0.95rem;
  color: var(--color-text);
}

.answer-option span {
  display: inline-flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 0.25rem;
  line-height: 1.4;
}

.answer-option input[type='radio'] {
  margin-top: 0.1rem;
}

.question-text .MathJax_Display,
.test-result-question .question-text .MathJax_Display,
.answer-option .MathJax_Display,
.test-result-question .answer-option .MathJax_Display {
  display: inline-block !important;
  margin: 0 0.25rem !important;
  vertical-align: middle;
  text-align: left !important;
}

.answer-list.readonly .answer-option {
  padding: 0.65rem;
  border-radius: 0.75rem;
  background: rgba(32, 33, 36, 0.03);
}

.answer-list.readonly .answer-option.answer-correct {
  background: rgba(46, 125, 50, 0.1);
  color: #1b5e20;
}

.answer-list.readonly .answer-option.answer-selected:not(.answer-correct) {
  background: rgba(220, 85, 63, 0.12);
  color: #7c1d16;
}

.answer-list.readonly .answer-empty {
  font-size: 0.95rem;
  color: var(--color-muted);
  background: transparent;
  padding-left: 0;
}

.test-submit {
  text-align: right;
}

.test-summary {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
  gap: 1rem;
  margin-bottom: 2rem;
}

.test-summary > div {
  background: var(--color-surface);
  border-radius: var(--radius-lg);
  padding: 1rem 1.25rem;
  border: 1px solid rgba(32, 33, 36, 0.08);
}

.summary-status-card {
  position: relative;
}

.summary-helper {
  margin: 0.15rem 0 0.35rem;
  font-size: 0.9rem;
  color: var(--color-muted);
}

.summary-status-card.summary-pass {
  background: rgba(46, 125, 50, 0.12);
  border-color: rgba(46, 125, 50, 0.3);
}

.summary-status-card.summary-fail {
  background: rgba(220, 85, 63, 0.12);
  border-color: rgba(220, 85, 63, 0.3);
}

.summary-status-pill {
  display: inline-flex;
  align-items: center;
  padding: 0.2rem 0.8rem;
  border-radius: 999px;
  font-weight: 600;
  font-size: 0.85rem;
}

.summary-status-pill.pill-pass {
  background: rgba(46, 125, 50, 0.2);
  color: #1b5e20;
}

.summary-status-pill.pill-fail {
  background: rgba(220, 85, 63, 0.2);
  color: #7c1d16;
}

.summary-label {
  margin: 0;
  color: var(--color-muted);
  font-size: 0.9rem;
}

.summary-value {
  margin: 0.35rem 0 0;
  font-size: 1.35rem;
  font-weight: 600;
}

.test-result-question.is-correct {
  border-color: rgba(46, 125, 50, 0.4);
}

.test-result-question.is-wrong {
  border-color: rgba(220, 85, 63, 0.3);
}

.admin-action-grid { grid-template-columns: repeat(auto-fit, minmax(320px, 1fr)); }

@media (max-width: 720px) {
  .admin-action-grid { grid-template-columns: 1fr; }
}

.admin-input-label {
  font-weight: 600;
  color: var(--color-text);
  font-size: 0.9rem;
}

.admin-long-btn {
  width: 100%;
  justify-content: center;
}

.test-attempt-page,
.test-result-page {
  padding-bottom: 3rem;
}

.sample-modal {
  position: fixed;
  inset: 0;
  display: none;
  z-index: 1200;
}

.sample-modal.is-visible {
  display: block;
}

.sample-modal[hidden] {
  display: none !important;
}

.sample-modal-backdrop {
  position: absolute;
  inset: 0;
  background: rgba(4, 7, 24, 0.75);
  backdrop-filter: blur(2px);
}

.sample-modal-dialog {
  position: relative;
  max-width: 960px;
  margin: 40px auto;
  background: #fff;
  border-radius: 18px;
  padding: 32px;
  box-shadow: 0 40px 120px rgba(15, 22, 44, 0.45);
  display: flex;
  flex-direction: column;
  gap: 20px;
  z-index: 1;
}

@media (max-width: 768px) {
  .sample-modal-dialog {
    margin: 20px;
    padding: 20px;
    max-width: calc(100% - 40px);
  }
}

.sample-modal-close {
  position: absolute;
  top: 12px;
  right: 12px;
  width: 36px;
  height: 36px;
  border-radius: 50%;
  border: none;
  background: rgba(13, 19, 38, 0.08);
  color: #0b1224;
  font-size: 22px;
  cursor: pointer;
  transition: background 0.2s ease;
}

.sample-modal-close:hover {
  background: rgba(13, 19, 38, 0.15);
}

.sample-modal-header {
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.sample-modal-title {
  font-size: 20px;
  font-weight: 600;
  margin: 0;
  color: #0b1224;
}

.sample-modal-group {
  margin: 0;
  color: #5c627a;
  font-size: 14px;
}

.sample-modal-status {
  font-size: 14px;
  color: #2d3352;
  background: rgba(13, 19, 38, 0.05);
  border-radius: 12px;
  padding: 10px 12px;
}

.sample-modal-status.is-error {
  color: #b42318;
  background: rgba(180, 35, 24, 0.08);
}

.sample-modal-status[hidden] {
  display: none !important;
}

.sample-modal-viewer {
  display: flex;
  align-items: center;
  gap: 16px;
}

.sample-modal-viewer[hidden] {
  display: none !important;
}

.sample-modal-nav {
  width: 48px;
  height: 48px;
  border-radius: 50%;
  border: none;
  background: linear-gradient(135deg, #3452ff, #5c7dff);
  color: #fff;
  font-size: 24px;
  cursor: pointer;
  flex-shrink: 0;
  transition: transform 0.2s ease, opacity 0.2s ease;
}

.sample-modal-nav:disabled {
  opacity: 0.4;
  cursor: default;
}

.sample-modal-nav:not(:disabled):hover {
  transform: translateY(-1px);
}

.sample-modal-frame {
  flex: 1;
  min-height: 320px;
  border-radius: 16px;
  border: 1px solid rgba(13, 19, 38, 0.12);
  background: #f9fafc;
  padding: 16px;
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.sample-modal-frame img {
  max-height: 60vh;
  width: 100%;
  object-fit: contain;
  border-radius: 8px;
  background: #fff;
  box-shadow: inset 0 0 0 1px rgba(13, 19, 38, 0.05);
  user-select: none;
  pointer-events: none;
}

.sample-modal-info {
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-size: 14px;
  color: #2d3352;
}

.sample-modal-label {
  font-weight: 600;
}

.sample-modal-counter {
  color: #5c627a;
}

.nav-contact {
  gap: 0.35rem;
  font-weight: 600;
  color: #fff;
}

.nav-contact:hover,
.nav-contact:focus {
  color: #fff;
}

.nav-contact-icon {
  font-size: 1.1rem;
  line-height: 1;
}

.course-diagram {
  margin: 0;
  border: 1px solid rgba(21, 32, 48, 0.08);
  border-radius: 16px;
  background: #fff;
  padding: 1rem 1.25rem;
}

.course-diagram summary {
  cursor: pointer;
  border-radius: 12px;
  padding: 0.9rem 1rem;
  border: 1px dashed rgba(91, 118, 255, 0.4);
  background: rgba(240, 244, 255, 0.95);
  font-weight: 600;
  font-size: 1rem;
  margin: 0;
  outline: none;
  list-style: none;
}

.course-diagram summary::-webkit-details-marker,
.course-diagram summary::marker {
  display: none;
}

.course-diagram-summary-content {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 0.75rem;
  color: #1f2670;
}

.course-diagram-summary-text span {
  display: block;
}

.course-diagram-summary-text small {
  display: block;
  font-size: 0.85rem;
  color: rgba(31, 38, 112, 0.7);
}

.course-diagram-toggle {
  font-size: 1.3rem;
  transition: transform 0.2s ease;
  color: #5b76ff;
}

.course-diagram[open] .course-diagram-toggle {
  transform: rotate(90deg);
}

.course-diagram-body {
  margin-top: 1.25rem;
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

.diagram-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}

.diagram-row-header {
  display: flex;
  align-items: baseline;
  gap: 0.5rem;
  font-weight: 600;
}

.diagram-status {
  font-size: 0.9rem;
  color: rgba(21, 32, 48, 0.6);
}

.diagram-bar span {
  font-family: 'SFMono-Regular', Consolas, 'Liberation Mono', Menlo, monospace;
  background: #f3f5f9;
  border-radius: 8px;
  padding: 0.25rem 0.5rem;
  display: inline-block;
}

.diagram-tips h4 {
  margin: 0 0 0.25rem;
}

.diagram-tips ul {
  margin: 0;
  padding-left: 1.2rem;
  color: rgba(21, 32, 48, 0.85);
}

.diagram-generated {
  margin: 0;
  font-size: 0.85rem;
  color: rgba(21, 32, 48, 0.6);
}

.diagram-tree {
  position: relative;
  display: flex;
  flex-direction: column;
  gap: 1.5rem;
  --diagram-padding-left: 2.5rem;
  padding-left: var(--diagram-padding-left);
  --diagram-line-color: #5673ff;
  --diagram-line-thickness: 2px;
  --diagram-line-offset: -26px; /* relative to cards */
  --diagram-line-center: calc(var(--diagram-padding-left) + var(--diagram-line-offset));
}

.diagram-tree::before {
  content: '';
  position: absolute;
  left: var(--diagram-line-center);
  top: 1.1rem;
  bottom: 1rem;
  border-left: var(--diagram-line-thickness) solid var(--diagram-line-color);
  z-index: 0;
}

.diagram-root-card {
  position: relative;
  display: flex;
  align-items: center;
  gap: 0.75rem;
  border: 1px solid rgba(21, 32, 48, 0.1);
  border-radius: 16px;
  padding: 0.85rem 1.1rem;
  background: linear-gradient(135deg, #f0f6ff, #fdfdff);
  box-shadow: 0 8px 24px rgba(21, 32, 48, 0.08);
}

.diagram-root-dot {
  width: 16px;
  height: 16px;
  border-radius: 50%;
  background: linear-gradient(135deg, #3f82f4, #73b5ff);
  position: absolute;
  left: calc(var(--diagram-line-offset) - 8px);
  top: 50%;
  transform: translateY(-50%);
  box-shadow: 0 0 0 6px rgba(63, 130, 244, 0.15);
}

.diagram-level-lane {
  position: relative;
  padding: 1rem 1.25rem 1.25rem 1.5rem;
  border-radius: 20px;
  border: 1px solid rgba(21, 32, 48, 0.07);
  background: #f9fbff;
  box-shadow: 0 14px 40px rgba(21, 32, 48, 0.06);
}

.diagram-level-lane::after {
  content: '';
  position: absolute;
  left: var(--diagram-line-offset);
  top: 24px;
  width: 24px;
  border-top: var(--diagram-line-thickness) solid var(--diagram-line-color);
}

.diagram-level-header {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  margin-bottom: 0.75rem;
}

.diagram-level-step {
  font-size: 0.8rem;
  font-weight: 700;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: #3f82f4;
  background: rgba(63, 130, 244, 0.12);
  border-radius: 999px;
  padding: 0.2rem 0.75rem;
}

.diagram-level-name {
  font-weight: 600;
  color: #152030;
}

.diagram-level-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 0.75rem;
}

.diagram-node {
  border-radius: 16px;
  border: 1px solid rgba(21, 32, 48, 0.08);
  background: #fff;
  padding: 0.85rem 1rem;
  box-shadow: 0 12px 32px rgba(21, 32, 48, 0.07);
  min-height: 140px;
  display: flex;
  flex-direction: column;
  gap: 0.35rem;
}

.diagram-node-head {
  display: flex;
  align-items: flex-start;
  gap: 0.65rem;
}

.diagram-node-order {
  width: 32px;
  height: 32px;
  border-radius: 50%;
  background: rgba(63, 130, 244, 0.15);
  color: #3f82f4;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  font-weight: 600;
  font-size: 0.95rem;
  flex: 0 0 32px;
  line-height: 1;
  margin-top: 0.1rem;
}

.diagram-node-summary {
  margin: 0;
  font-size: 0.9rem;
  color: rgba(21, 32, 48, 0.75);
}

.diagram-node-deps {
  margin-top: auto;
  display: flex;
  flex-wrap: wrap;
  gap: 0.35rem;
  align-items: center;
}

.diagram-node-chips {
  display: inline-flex;
  flex-wrap: wrap;
  gap: 0.35rem;
}

.diagram-node-chip {
  display: inline-flex;
  align-items: center;
  border-radius: 999px;
  background: rgba(21, 32, 48, 0.08);
  color: #152030;
  font-size: 0.78rem;
  padding: 0.15rem 0.6rem;
}

.diagram-node-chip-free {
  background: rgba(43, 196, 138, 0.15);
  color: #189b66;
}

.diagram-node-chip-warn {
  background: rgba(220, 53, 69, 0.12);
  color: #b3182c;
  border: 1px solid rgba(220, 53, 69, 0.35);
  font-weight: 600;
}