/* ===== CSS Variables ===== */
:root {
  --primary: #2b7a9e;
  --primary-dark: #1d5f7e;
  --primary-light: #e8f4f8;
  --bg: #f5f7fa;
  --white: #ffffff;
  --text: #2d3436;
  --text-secondary: #636e72;
  --text-muted: #b2bec3;
  --success: #00b894;
  --success-light: #e6f9f3;
  --danger: #d63031;
  --danger-light: #fde8e8;
  --warning: #fdcb6e;
  --border: #dfe6e9;
  --shadow: 0 2px 8px rgba(0,0,0,0.08);
  --shadow-lg: 0 4px 16px rgba(0,0,0,0.12);
  --radius: 8px;
  --radius-sm: 4px;
}

/* ===== Reset ===== */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, sans-serif;
  color: var(--text);
  background: var(--bg);
  line-height: 1.6;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

/* ===== Header ===== */
.site-header {
  background: var(--white);
  border-bottom: 2px solid var(--border);
  box-shadow: var(--shadow);
}

.header-logo {
  text-align: center;
  padding: 0.5rem 1rem;
  background: var(--white);
}

.logo-img {
  max-width: 100%;
  height: auto;
  max-height: 100px;
}

.main-nav {
  display: flex;
  align-items: center;
  gap: 0.25rem;
  padding: 0.5rem 1rem;
  background: var(--primary);
  flex-wrap: wrap;
}

.main-nav a {
  color: rgba(255,255,255,0.85);
  text-decoration: none;
  padding: 0.4rem 0.8rem;
  border-radius: var(--radius-sm);
  font-size: 0.9rem;
  transition: background 0.2s, color 0.2s;
}

.main-nav a:hover,
.main-nav a.active {
  background: rgba(255,255,255,0.2);
  color: #fff;
}

.nav-info {
  color: rgba(255,255,255,0.8);
  font-size: 0.85rem;
  margin-left: auto;
  padding: 0.4rem 0.8rem;
}

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

.btn-link {
  background: none;
  border: none;
  color: rgba(255,255,255,0.85);
  cursor: pointer;
  font-size: 0.9rem;
  padding: 0.4rem 0.8rem;
  border-radius: var(--radius-sm);
  transition: background 0.2s;
}

.btn-link:hover {
  background: rgba(255,255,255,0.2);
  color: #fff;
}

/* ===== Main Content ===== */
.main-content {
  flex: 1;
  padding: 2rem 1rem;
  max-width: 1200px;
  width: 100%;
  margin: 0 auto;
}

/* ===== Footer ===== */
.site-footer {
  text-align: center;
  padding: 1.5rem;
  color: var(--text-secondary);
  font-size: 0.85rem;
  border-top: 1px solid var(--border);
  background: var(--white);
}

/* ===== Containers ===== */
.container {
  max-width: 1100px;
  margin: 0 auto;
}

.home-container {
  text-align: center;
  padding: 3rem 1rem;
}

.home-container h1 {
  font-size: 2.5rem;
  color: var(--primary);
  margin-bottom: 0.5rem;
}

.subtitle {
  color: var(--text-secondary);
  font-size: 1.2rem;
  margin-bottom: 2rem;
}

.home-links {
  display: flex;
  gap: 1.5rem;
  justify-content: center;
  flex-wrap: wrap;
  margin-bottom: 2rem;
}

.home-info {
  color: var(--text-secondary);
  max-width: 600px;
  margin: 0 auto;
  padding: 1.5rem;
  background: var(--primary-light);
  border-radius: var(--radius);
}

/* ===== Login ===== */
.login-container {
  max-width: 400px;
  margin: 3rem auto;
  text-align: center;
}

.login-form {
  background: var(--white);
  padding: 2rem;
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  margin-top: 1.5rem;
  text-align: left;
}

.login-back {
  margin-top: 1rem;
  font-size: 0.9rem;
}

.login-back a {
  color: var(--primary);
}

/* ===== Buttons ===== */
.btn {
  display: inline-block;
  padding: 0.6rem 1.2rem;
  border: none;
  border-radius: var(--radius-sm);
  cursor: pointer;
  font-size: 0.95rem;
  font-weight: 500;
  text-decoration: none;
  text-align: center;
  transition: background 0.2s, transform 0.1s;
  line-height: 1.4;
}

.btn:hover {
  transform: translateY(-1px);
}

.btn:active {
  transform: translateY(0);
}

.btn-primary {
  background: var(--primary);
  color: #fff;
}

.btn-primary:hover {
  background: var(--primary-dark);
}

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

.btn-secondary:hover {
  background: #c8d1d5;
}

.btn-danger {
  background: var(--danger);
  color: #fff;
}

.btn-danger:hover {
  background: #c0392b;
}

.btn-danger-outline {
  background: transparent;
  color: var(--danger);
  border: 2px solid var(--danger);
}

.btn-danger-outline:hover {
  background: var(--danger);
  color: #fff;
}

.btn-large {
  padding: 1rem 2.5rem;
  font-size: 1.1rem;
}

.btn-small {
  padding: 0.3rem 0.6rem;
  font-size: 0.8rem;
}

/* ===== Forms ===== */
.form-card {
  background: var(--white);
  padding: 2rem;
  border-radius: var(--radius);
  box-shadow: var(--shadow);
}

.form-group {
  margin-bottom: 1.2rem;
}

.form-group label {
  display: block;
  font-weight: 600;
  margin-bottom: 0.4rem;
  font-size: 0.9rem;
}

.form-control {
  width: 100%;
  padding: 0.6rem 0.8rem;
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  font-size: 0.95rem;
  font-family: inherit;
  transition: border-color 0.2s;
}

.form-control:focus {
  outline: none;
  border-color: var(--primary);
  box-shadow: 0 0 0 3px rgba(43, 122, 158, 0.15);
}

.form-row {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 1rem;
}

.form-actions {
  margin-top: 1.5rem;
  display: flex;
  gap: 0.75rem;
  flex-wrap: wrap;
}

.form-hint {
  font-size: 0.8rem;
  color: var(--text-secondary);
  margin-top: 0.2rem;
}

.class-picker {
  display: flex;
  gap: 0.5rem;
}

.class-picker .form-control {
  flex: 1;
}

.form-inline {
  display: flex;
  align-items: flex-end;
  gap: 1rem;
  flex-wrap: wrap;
}

.form-inline .form-group {
  margin-bottom: 0;
  flex: 1;
}

.checkbox-label {
  display: flex !important;
  align-items: center;
  gap: 0.5rem;
  font-weight: normal !important;
  cursor: pointer;
}

.checkbox-label input[type="checkbox"] {
  width: auto;
}

/* ===== Alerts ===== */
.alert {
  padding: 0.8rem 1.2rem;
  border-radius: var(--radius-sm);
  margin-bottom: 1rem;
  font-size: 0.9rem;
}

.alert-success {
  background: var(--success-light);
  color: #00856b;
  border: 1px solid #00b894;
}

.alert-error {
  background: var(--danger-light);
  color: #c0392b;
  border: 1px solid var(--danger);
}

.alert-info {
  background: var(--primary-light);
  color: var(--primary-dark);
  border: 1px solid var(--primary);
}

/* ===== Cards ===== */
.card {
  background: var(--white);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 1.5rem;
  margin-bottom: 1rem;
}

/* ===== Stats Grid (Dashboard) ===== */
.stats-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 1rem;
  margin-bottom: 2rem;
}

.stat-card {
  background: var(--white);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 1.5rem;
  text-align: center;
  border-top: 4px solid var(--primary);
}

.stat-number {
  font-size: 2.5rem;
  font-weight: 700;
  color: var(--primary);
}

.stat-label {
  color: var(--text-secondary);
  margin-bottom: 0.5rem;
}

.stat-link {
  color: var(--primary);
  text-decoration: none;
  font-size: 0.85rem;
}

.stat-link:hover {
  text-decoration: underline;
}

.dashboard-section {
  margin-bottom: 2rem;
}

.dashboard-section-title {
  font-size: 1.15rem;
  color: var(--text-secondary);
  margin-bottom: 0.75rem;
  border-bottom: 1px solid var(--border);
  padding-bottom: 0.4rem;
}

.stat-card-success { border-top-color: var(--success); }
.stat-card-success .stat-number { color: var(--success); }

.stat-card-warning { border-top-color: var(--warning); }
.stat-card-warning .stat-number { color: #c48b1b; }

.stat-card-danger { border-top-color: var(--danger); }
.stat-card-danger .stat-number { color: var(--danger); }

.stat-card-muted { border-top-color: var(--text-muted); }
.stat-card-muted .stat-number { color: var(--text-secondary); }

.stat-subtext {
  font-size: 1rem;
  font-weight: 400;
  color: var(--text-secondary);
  margin-left: 0.25rem;
}

.stat-sub {
  font-size: 0.8rem;
  color: var(--text-secondary);
  margin-top: 0.25rem;
}

.stat-progress {
  height: 6px;
  background: var(--border);
  border-radius: 3px;
  overflow: hidden;
  margin-top: 0.5rem;
}

.stat-progress-bar {
  height: 100%;
  background: var(--success);
  transition: width 0.3s ease;
}

/* Teacher detail: workshop cards */
.workshop-header {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 1rem;
  flex-wrap: wrap;
  margin-bottom: 0.5rem;
}

.workshop-meta {
  color: var(--text-secondary);
  font-size: 0.9rem;
}

.workshop-actions {
  display: flex;
  gap: 0.5rem;
  margin-top: 0.75rem;
  flex-wrap: wrap;
}

/* ===== Action Grid ===== */
.actions-bar {
  margin-bottom: 1.5rem;
  display: flex;
  gap: 0.75rem;
  flex-wrap: wrap;
}

.action-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 0.75rem;
}

.quick-actions h2 {
  margin-bottom: 1rem;
}

/* ===== Tables ===== */
.table-responsive {
  overflow-x: auto;
  margin-bottom: 1rem;
}

.data-table {
  width: 100%;
  border-collapse: collapse;
  background: var(--white);
  border-radius: var(--radius);
  overflow: hidden;
  box-shadow: var(--shadow);
}

.data-table thead {
  background: var(--primary-light);
}

.data-table th {
  text-align: left;
  padding: 0.75rem 1rem;
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--primary-dark);
  border-bottom: 2px solid var(--border);
}

.data-table td {
  padding: 0.65rem 1rem;
  border-bottom: 1px solid var(--border);
  font-size: 0.9rem;
}

.data-table tbody tr:hover {
  background: #f8f9fa;
}

.data-table .actions {
  white-space: nowrap;
  display: flex;
  gap: 0.3rem;
  align-items: center;
}

/* ===== Workshop Cards (Student View) ===== */
.student-container {
  max-width: 900px;
  margin: 0 auto;
}

.student-header {
  text-align: center;
  margin-bottom: 1.5rem;
}

.student-header h1 {
  color: var(--primary);
}

.student-info {
  color: var(--text-secondary);
  font-size: 1rem;
}

.workshop-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: 1.2rem;
  margin-top: 1rem;
}

.workshop-card {
  background: var(--white);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 1.5rem;
  display: flex;
  flex-direction: column;
  transition: box-shadow 0.2s, transform 0.2s;
  border: 2px solid transparent;
}

.workshop-card:hover {
  box-shadow: var(--shadow-lg);
  transform: translateY(-2px);
  border-color: var(--primary-light);
}

.workshop-card-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 0.75rem;
}

.timeslot-badge {
  background: var(--primary);
  color: #fff;
  padding: 0.2rem 0.6rem;
  border-radius: 20px;
  font-size: 0.75rem;
  font-weight: 600;
}

.timeslot-badge-small {
  background: var(--primary-light);
  color: var(--primary-dark);
  padding: 0.15rem 0.5rem;
  border-radius: 20px;
  font-size: 0.75rem;
  font-weight: 600;
}

.spots-badge {
  background: var(--success-light);
  color: #00856b;
  padding: 0.2rem 0.6rem;
  border-radius: 20px;
  font-size: 0.75rem;
  font-weight: 600;
}

.workshop-title {
  font-size: 1.15rem;
  margin-bottom: 0.4rem;
}

.workshop-teacher {
  color: var(--text-secondary);
  font-size: 0.9rem;
  margin-bottom: 0.5rem;
}

.workshop-description {
  color: var(--text);
  font-size: 0.85rem;
  margin-bottom: 0.75rem;
  flex: 1;
}

.workshop-timeslot {
  color: var(--text-muted);
  font-size: 0.8rem;
  margin-bottom: 1rem;
}

.btn-enroll {
  width: 100%;
}

.enroll-form {
  margin-top: auto;
}

/* Already enrolled section */
.already-enrolled {
  background: var(--primary-light);
  border: 1px solid var(--primary);
}

.enrollment-list {
  list-style: none;
  padding: 0;
}

.enrollment-list li {
  padding: 0.3rem 0;
}

/* Summary cards */
.success-card {
  background: var(--success-light);
  border: 2px solid var(--success);
}

.summary-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 1rem;
  margin-top: 1rem;
}

.summary-card {
  background: var(--white);
  border-radius: var(--radius);
  padding: 1.2rem;
  box-shadow: var(--shadow);
}

.summary-timeslot {
  color: var(--primary);
  font-weight: 600;
  font-size: 0.85rem;
  margin-bottom: 0.3rem;
}

/* ===== Class Filter ===== */
.class-filter {
  margin-bottom: 1.5rem;
}

.class-filter label {
  display: block;
  margin-bottom: 0.5rem;
  font-weight: 600;
  font-size: 0.9rem;
}

.class-buttons {
  display: flex;
  gap: 0.4rem;
  flex-wrap: wrap;
}

/* ===== Sortable table headers ===== */
.sort-link {
  color: inherit;
  text-decoration: none;
  display: inline-block;
  white-space: nowrap;
}
.sort-link:hover {
  text-decoration: underline;
}
.sort-link.active {
  color: var(--primary-dark);
}

/* ===== Tags ===== */
.tag {
  display: inline-block;
  background: var(--primary-light);
  color: var(--primary-dark);
  padding: 0.15rem 0.5rem;
  border-radius: 20px;
  font-size: 0.75rem;
  margin: 0.1rem;
}

/* ===== Text utilities ===== */
.text-danger { color: var(--danger); }
.text-muted { color: var(--text-muted); }
.result-count {
  color: var(--text-secondary);
  font-size: 0.9rem;
  margin-bottom: 0.75rem;
}

/* ===== Link table ===== */
.link-cell {
  font-family: 'Courier New', monospace;
  font-size: 0.8rem;
  word-break: break-all;
}

/* ===== Code block ===== */
.code-block {
  background: #f1f3f5;
  padding: 1rem;
  border-radius: var(--radius-sm);
  font-family: 'Courier New', monospace;
  font-size: 0.85rem;
  overflow-x: auto;
  margin: 0.75rem 0;
}

/* ===== Export Grid ===== */
.export-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(250px, 1fr));
  gap: 1rem;
}

/* ===== Reset ===== */
.reset-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 1rem;
  margin-top: 1rem;
}

.reset-card {
  border: 1px solid var(--border);
}

.reset-all {
  grid-column: 1 / -1;
  border-color: var(--danger);
  background: var(--danger-light);
  text-align: center;
}

/* ===== Modal ===== */
.modal-overlay {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: rgba(0, 0, 0, 0.5);
  backdrop-filter: blur(4px);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 1000;
}

.modal-content {
  background: var(--white);
  border-radius: var(--radius);
  padding: 2rem;
  max-width: 450px;
  width: 90%;
  box-shadow: var(--shadow-lg);
  text-align: center;
}

.modal-content h2 {
  margin-bottom: 1rem;
  color: var(--text);
}

.modal-content p {
  margin-bottom: 1.5rem;
  color: var(--text-secondary);
}

.modal-buttons {
  display: flex;
  gap: 0.75rem;
  justify-content: center;
}

/* ===== Error Page ===== */
.error-container {
  text-align: center;
  padding: 3rem 1rem;
  max-width: 600px;
  margin: 0 auto;
}

.error-container h1 {
  color: var(--danger);
  margin-bottom: 1rem;
}

.error-stack {
  text-align: left;
  background: #f1f3f5;
  padding: 1rem;
  border-radius: var(--radius-sm);
  font-size: 0.8rem;
  margin: 1rem 0;
  overflow-x: auto;
}

/* ===== Responsive ===== */
@media (max-width: 768px) {
  .main-content {
    padding: 1rem;
  }

  .home-container h1 {
    font-size: 1.8rem;
  }

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

  .stats-grid {
    grid-template-columns: repeat(2, 1fr);
  }

  .form-row {
    grid-template-columns: 1fr;
  }

  .main-nav {
    justify-content: center;
  }

  .nav-info {
    margin-left: 0;
    width: 100%;
    text-align: center;
  }

  .data-table .actions {
    flex-direction: column;
  }
}

@media (max-width: 480px) {
  .stats-grid {
    grid-template-columns: 1fr;
  }

  .btn-large {
    width: 100%;
  }
}

/* Workshop print table: hidden on screen, shown in print */
.workshop-print-table {
  display: none;
}

.print-description {
  color: #555;
  font-style: italic;
}

.print-summary {
  margin-top: 1rem;
  font-size: 0.9rem;
  color: #666;
  text-align: right;
}