:root {
  --primary: #4a90d9;
  --primary-light: #e8f1fb;
  --success: #5cb85c;
  --success-light: #edf7ed;
  --warning: #f0ad4e;
  --warning-light: #fef8ec;
  --danger: #d9534f;
  --danger-light: #fbeaea;
  --bg: #faf9f7;
  --card-bg: #ffffff;
  --text: #333333;
  --text-light: #777777;
  --border: #e0ddd8;
  --radius: 12px;
  --shadow: 0 2px 8px rgba(0,0,0,0.06);
  --shadow-hover: 0 4px 16px rgba(0,0,0,0.1);
  --font: -apple-system, BlinkMacSystemFont, "Segoe UI", "Noto Sans TC", sans-serif;
}

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

body {
  font-family: var(--font);
  font-size: 17px;
  line-height: 1.7;
  color: var(--text);
  background: var(--bg);
  min-height: 100vh;
}

.container { max-width: 860px; margin: 0 auto; padding: 0 20px; }

a { color: var(--primary); text-decoration: none; }
a:hover { text-decoration: underline; }

.nav {
  background: var(--card-bg);
  border-bottom: 1px solid var(--border);
  padding: 14px 0;
  position: sticky;
  top: 0;
  z-index: 100;
}
.nav .container { display: flex; justify-content: space-between; align-items: center; }
.nav-brand { font-size: 20px; font-weight: 700; color: var(--text); }
.nav-links { display: flex; gap: 20px; }
.nav-links a { font-size: 15px; color: var(--text-light); padding: 4px 12px; border-radius: 6px; }
.nav-links a:hover { background: var(--primary-light); color: var(--primary); text-decoration: none; }

.page-header { padding: 32px 0 16px; }
.page-header h1 { font-size: 26px; font-weight: 700; }
.page-header p { color: var(--text-light); margin-top: 4px; }

.card {
  background: var(--card-bg);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 28px;
  margin-bottom: 20px;
}
.card h2 { font-size: 20px; margin-bottom: 16px; }
.card h3 { font-size: 17px; margin-bottom: 12px; color: var(--text-light); }

.card-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(280px, 1fr)); gap: 16px; margin-top: 16px; }
.card-link {
  display: block;
  border: 2px solid var(--border);
  border-radius: var(--radius);
  padding: 24px;
  transition: all 0.15s;
  background: var(--card-bg);
}
.card-link:hover {
  border-color: var(--primary);
  box-shadow: var(--shadow-hover);
  text-decoration: none;
  transform: translateY(-2px);
}
.card-link h3 { color: var(--text); margin-bottom: 6px; }
.card-link p { color: var(--text-light); font-size: 15px; }

.form-group { margin-bottom: 20px; }
.form-label { display: block; font-weight: 600; margin-bottom: 6px; font-size: 16px; }
.form-input, .form-textarea {
  width: 100%;
  padding: 12px 14px;
  border: 1.5px solid var(--border);
  border-radius: 8px;
  font-family: var(--font);
  font-size: 16px;
  transition: border-color 0.15s;
  background: #fff;
}
.form-input:focus, .form-textarea:focus {
  outline: none;
  border-color: var(--primary);
  box-shadow: 0 0 0 3px rgba(74,144,217,0.12);
}
.form-textarea { min-height: 100px; resize: vertical; }
.form-textarea.short { min-height: 60px; }

.btn {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 12px 28px;
  border: none;
  border-radius: 8px;
  font-family: var(--font);
  font-size: 16px;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.15s;
}
.btn-primary { background: var(--primary); color: #fff; }
.btn-primary:hover { background: #3a7bc8; }
.btn-secondary { background: var(--border); color: var(--text); }
.btn-secondary:hover { background: #d0ccc6; }
.btn-success { background: var(--success); color: #fff; }
.btn-success:hover { background: #4cae4c; }
.btn-sm { padding: 6px 14px; font-size: 14px; }

.alert {
  padding: 14px 18px;
  border-radius: 8px;
  margin-bottom: 20px;
  font-size: 15px;
}
.alert-error { background: var(--danger-light); color: var(--danger); border: 1px solid #f1c0bf; }
.alert-success { background: var(--success-light); color: #3c763d; border: 1px solid #c3e6c3; }

.teacher-comment {
  background: linear-gradient(135deg, #fffde7 0%, #fff9c4 100%);
  border: 2px solid #f9e547;
  border-radius: var(--radius);
  padding: 24px 28px;
  font-size: 18px;
  line-height: 1.8;
  position: relative;
  margin: 16px 0;
}
.teacher-comment::before {
  content: "\1F4DD";
  position: absolute;
  top: -14px;
  left: 20px;
  font-size: 24px;
  background: #fffde7;
  padding: 0 6px;
}

.answer-display { padding: 10px 0; }
.answer-field { margin-bottom: 14px; }
.answer-label { font-weight: 600; font-size: 14px; color: var(--text-light); margin-bottom: 2px; }
.answer-value { padding: 8px 12px; background: #f8f7f5; border-radius: 6px; }

.emotion-wheel { display: grid; grid-template-columns: repeat(auto-fill, minmax(200px, 1fr)); gap: 12px; margin-top: 12px; }
.emotion-slot {
  border: 1.5px solid var(--border);
  border-radius: 10px;
  padding: 14px;
  background: #fff;
}
.emotion-slot--fixed { background: #f0faf0; border-color: #b8d8b8; }
.slot-number { font-size: 13px; font-weight: 700; color: var(--text-light); margin-bottom: 8px; }
.emotion-slot .form-input { margin-bottom: 8px; padding: 8px 10px; font-size: 15px; }
.emotion-slot .form-textarea { min-height: 60px; font-size: 15px; }
.fixed-label { font-weight: 600; padding: 6px 0 10px; color: #3c763d; font-size: 15px; }

.emotion-display {
  display: inline-block;
  padding: 4px 10px;
  border-radius: 20px;
  font-size: 14px;
  font-weight: 600;
  margin: 2px;
}

.score-row { display: flex; align-items: center; gap: 12px; margin-bottom: 10px; }
.score-label { width: 80px; font-size: 14px; font-weight: 600; text-align: right; flex-shrink: 0; }
.score-bar-bg { flex: 1; height: 22px; background: #eee; border-radius: 11px; overflow: hidden; }
.score-bar {
  height: 100%;
  border-radius: 11px;
  background: linear-gradient(90deg, var(--primary-light), var(--primary));
  transition: width 0.3s;
}
.score-value { width: 36px; font-size: 14px; font-weight: 700; color: var(--primary); }

.badge {
  display: inline-block;
  padding: 3px 10px;
  border-radius: 20px;
  font-size: 13px;
  font-weight: 600;
}
.badge-success { background: var(--success-light); color: #3c763d; }
.badge-warning { background: var(--warning-light); color: #8a6d3b; }
.badge-danger { background: var(--danger-light); color: var(--danger); }
.badge-info { background: var(--primary-light); color: var(--primary); }
.badge-muted { background: #f0f0f0; color: var(--text-light); }

.badge-list { display: flex; flex-wrap: wrap; gap: 6px; margin: 6px 0; }

.status-pending { color: var(--text-light); }
.status-grading { color: var(--warning); }
.status-completed { color: var(--success); }
.status-error { color: var(--danger); }

.table-wrap { overflow-x: auto; }
table { width: 100%; border-collapse: collapse; font-size: 15px; }
th { text-align: left; padding: 10px 12px; border-bottom: 2px solid var(--border); font-size: 14px; color: var(--text-light); }
td { padding: 12px; border-bottom: 1px solid #f0eeea; }
tr:hover td { background: #faf9f7; }

.section { margin-bottom: 28px; }
.section-title { font-size: 18px; font-weight: 700; margin-bottom: 12px; padding-bottom: 6px; border-bottom: 2px solid var(--border); }

.detail-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 12px; }
.detail-item .detail-label { font-size: 13px; color: var(--text-light); }
.detail-item .detail-value { font-weight: 600; }

.loading-overlay {
  display: none;
  position: fixed;
  inset: 0;
  background: rgba(255,255,255,0.92);
  z-index: 1000;
  justify-content: center;
  align-items: center;
  flex-direction: column;
  gap: 20px;
}
.loading-overlay.active { display: flex; }
.spinner {
  width: 48px;
  height: 48px;
  border: 4px solid var(--border);
  border-top-color: var(--primary);
  border-radius: 50%;
  animation: spin 0.8s linear infinite;
}
@keyframes spin { to { transform: rotate(360deg); } }
.loading-text { font-size: 18px; color: var(--text); text-align: center; }

.empty-state {
  text-align: center;
  padding: 60px 20px;
  color: var(--text-light);
}
.empty-state p { font-size: 18px; }

footer {
  text-align: center;
  padding: 24px 0;
  color: var(--text-light);
  font-size: 13px;
  border-top: 1px solid var(--border);
  margin-top: 40px;
}

@media (max-width: 768px) {
  body { font-size: 16px; }
  .container { padding: 0 14px; }
  .card { padding: 18px; }
  .emotion-wheel { grid-template-columns: 1fr 1fr; }
  .detail-grid { grid-template-columns: 1fr; }
  .card-grid { grid-template-columns: 1fr; }
}

@media print {
  .nav, .btn, footer, .loading-overlay { display: none; }
  .card { box-shadow: none; border: 1px solid #ccc; }
}

/* === Collapsible AI Analysis === */
.ai-analysis-details { border: none; }
.ai-analysis-details > summary { list-style: none; cursor: pointer; }
.ai-analysis-details > summary::-webkit-details-marker { display: none; }
.section-title--collapsible {
  display: flex;
  align-items: center;
  gap: 10px;
  cursor: pointer;
  user-select: none;
}
.section-title--collapsible:hover { color: var(--primary); }
.collapse-hint {
  font-size: 13px;
  font-weight: 400;
  color: var(--text-light);
  padding: 2px 8px;
  background: #f0f0f0;
  border-radius: 4px;
}
.ai-analysis-details[open] .collapse-hint { display: none; }

/* === Auth / Nav User === */
.nav-user {
  display: flex;
  align-items: center;
  gap: 6px;
  font-size: 14px;
  color: var(--text);
  font-weight: 600;
}
.nav-avatar {
  width: 28px;
  height: 28px;
  border-radius: 50%;
  object-fit: cover;
}
.nav-logout {
  font-size: 13px;
  color: var(--text-light) !important;
  padding: 2px 8px;
}
.nav-login-btn {
  padding: 6px 16px !important;
  font-size: 13px !important;
  color: #fff !important;
  text-decoration: none !important;
}