:root {
  --bg: #f5faf9;
  --card: rgba(255, 255, 255, 0.88);
  --text: #0f172a;
  --muted: #64748b;
  --primary: #0f766e;
  --primary-2: #14b8a6;
  --accent: #7c3aed;
  --border: rgba(15, 118, 110, 0.1);
  --shadow: 0 18px 48px rgba(15, 23, 42, 0.12);
  --teacher-bg: #f0f4f8;
  --teacher-primary: #1e3a5f;
  --teacher-accent: #2563eb;
  --teacher-card: rgba(255, 255, 255, 0.92);
  --red: #ef4444;
  --orange: #f59e0b;
  --green: #10b981;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  font-family: "PingFang SC", "Microsoft YaHei", sans-serif;
  color: var(--text);
  background:
    radial-gradient(circle at top left, rgba(20, 184, 166, 0.18), transparent 28%),
    radial-gradient(circle at top right, rgba(124, 58, 237, 0.12), transparent 24%),
    linear-gradient(180deg, #e9fffb 0%, var(--bg) 28%, #f8fafc 100%);
  min-height: 100vh;
}

body.teacher-mode {
  background:
    radial-gradient(circle at top left, rgba(30, 58, 95, 0.08), transparent 28%),
    radial-gradient(circle at top right, rgba(37, 99, 235, 0.06), transparent 24%),
    linear-gradient(180deg, #eef2f6 0%, var(--teacher-bg) 28%, #f8fafc 100%);
}

button, input, select { font: inherit; }

/* ==================== 角色选择层 ==================== */
.role-gate {
  position: fixed;
  inset: 0;
  z-index: 1000;
  display: flex;
  align-items: center;
  justify-content: center;
  background:
    radial-gradient(circle at 20% 30%, rgba(20, 184, 166, 0.2), transparent 40%),
    radial-gradient(circle at 80% 70%, rgba(124, 58, 237, 0.15), transparent 40%),
    linear-gradient(180deg, #e9fffb, #f0f4f8, #f8fafc);
  padding: 24px;
  transition: opacity 0.35s, visibility 0.35s;
}

.role-gate.hidden {
  opacity: 0;
  visibility: hidden;
  pointer-events: none;
}

.role-gate-card {
  text-align: center;
  max-width: 520px;
  width: 100%;
}

.role-gate-icon {
  font-size: 64px;
  margin-bottom: 16px;
}

.role-gate-card h1 {
  margin: 0 0 8px;
  font-size: clamp(28px, 4vw, 40px);
  color: var(--text);
}

.role-gate-desc {
  margin: 0 0 32px;
  color: var(--muted);
  font-size: 16px;
}

.role-gate-buttons {
  display: grid;
  gap: 16px;
}

.role-btn {
  display: flex;
  align-items: center;
  gap: 16px;
  width: 100%;
  padding: 20px 24px;
  border: 2px solid transparent;
  border-radius: 20px;
  cursor: pointer;
  text-align: left;
  transition: all 0.25s;
  background: white;
  box-shadow: 0 8px 30px rgba(15, 23, 42, 0.08);
}

.role-btn:hover {
  transform: translateY(-3px);
  box-shadow: 0 14px 40px rgba(15, 23, 42, 0.14);
}

.student-btn {
  border-color: rgba(15, 118, 110, 0.2);
}

.student-btn:hover {
  border-color: var(--primary);
  background: linear-gradient(135deg, rgba(15, 118, 110, 0.04), rgba(20, 184, 166, 0.08));
}

.teacher-btn {
  border-color: rgba(37, 99, 235, 0.2);
}

.teacher-btn:hover {
  border-color: var(--teacher-accent);
  background: linear-gradient(135deg, rgba(30, 58, 95, 0.04), rgba(37, 99, 235, 0.08));
}

.role-btn-icon {
  font-size: 36px;
  flex-shrink: 0;
}

.role-btn-text strong {
  display: block;
  font-size: 18px;
  margin-bottom: 4px;
  color: var(--text);
}

.role-btn-text small {
  display: block;
  font-size: 14px;
  color: var(--muted);
}

/* ==================== 顶部角色栏 ==================== */
.top-bar {
  background: white;
  border-bottom: 1px solid #e2e8f0;
  padding: 0 24px;
  position: sticky;
  top: 0;
  z-index: 100;
  box-shadow: 0 1px 8px rgba(15, 23, 42, 0.06);
}

.top-bar-inner {
  max-width: 1440px;
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 52px;
}

.top-bar-role {
  font-weight: 700;
  font-size: 15px;
}

.top-bar-switch {
  padding: 6px 16px;
  border-radius: 12px;
  border: 1px solid #dbe4ea;
  background: #f8fafc;
  cursor: pointer;
  font-size: 13px;
  color: var(--muted);
  transition: all 0.2s;
}

.top-bar-switch:hover {
  background: #e2e8f0;
  border-color: #94a3b8;
}

/* ==================== App Shell ==================== */
.app-shell {
  max-width: 1440px;
  margin: 0 auto;
  padding: 24px;
}

.card {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 24px;
  box-shadow: var(--shadow);
  backdrop-filter: blur(10px);
}

/* ==================== Hero ==================== */
.hero {
  display: grid;
  grid-template-columns: 1.7fr 1fr;
  gap: 20px;
  padding: 28px;
  color: white;
  margin-bottom: 22px;
}

.hero-student {
  background: linear-gradient(135deg, rgba(15, 118, 110, 0.95), rgba(20, 184, 166, 0.84));
  grid-template-columns: 1fr;
}

.hero-teacher {
  background: linear-gradient(135deg, rgba(30, 58, 95, 0.95), rgba(37, 99, 235, 0.84));
}

.hero h1 {
  margin: 10px 0 12px;
  font-size: clamp(30px, 4vw, 48px);
}

.hero p {
  margin: 0;
  max-width: 58ch;
  color: rgba(255, 255, 255, 0.92);
  line-height: 1.8;
}

.badge {
  display: inline-flex;
  padding: 8px 14px;
  border-radius: 999px;
  background: rgba(255, 255, 255, 0.16);
  font-size: 13px;
  letter-spacing: .08em;
}

.hero-stats {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 12px;
  align-items: center;
}

.hero-stats div {
  padding: 16px 14px;
  border-radius: 18px;
  background: rgba(255, 255, 255, 0.14);
  text-align: center;
}

.hero-stats strong {
  display: block;
  font-size: 30px;
}

.hero-stats span {
  display: block;
  margin-top: 6px;
  font-size: 13px;
  color: rgba(255, 255, 255, 0.84);
}

/* ==================== Grid Layout ==================== */
.grid-layout {
  display: grid;
  grid-template-columns: minmax(0, 1.3fr) minmax(320px, 0.8fr);
  gap: 22px;
}

.student-layout {
  grid-template-columns: minmax(0, 1fr);
  max-width: 980px;
  margin: 0 auto;
}

.teacher-layout {
  grid-template-columns: minmax(0, 1.5fr) minmax(340px, 0.7fr);
}

.left-column, .right-column { display: grid; gap: 22px; }

/* ==================== Panels ==================== */
.panel, .actions, .result-card { padding: 22px; }

.panel-head {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  gap: 12px;
  margin-bottom: 16px;
}

.panel-head h2 { margin: 0; font-size: 22px; }
.panel-head span { color: var(--muted); font-size: 14px; }

/* ==================== Form Fields ==================== */
.field {
  display: grid;
  gap: 8px;
  margin-bottom: 16px;
}

.field > span { color: var(--muted); font-size: 14px; }

.field input, .field select {
  width: 100%;
  padding: 14px 16px;
  border-radius: 16px;
  border: 1px solid #dbe4ea;
  background: #f8fafc;
  color: var(--text);
  outline: none;
}

.field input:focus, .field select:focus {
  border-color: rgba(15, 118, 110, 0.55);
  box-shadow: 0 0 0 4px rgba(20, 184, 166, 0.15);
}

/* ==================== Filter Bar ==================== */
.filter-bar { padding-bottom: 10px; }

.filter-row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 16px;
}

.filter-field { margin-bottom: 8px; }

/* ==================== Progress Bar ==================== */
.progress-bar {
  height: 10px;
  border-radius: 999px;
  overflow: hidden;
  background: #e2e8f0;
  margin-bottom: 16px;
}

#student-progress-fill {
  width: 0;
  height: 100%;
  border-radius: inherit;
  background: linear-gradient(90deg, var(--primary), var(--primary-2));
}

/* ==================== Questions ==================== */
.questions { display: grid; gap: 16px; }

.question-card {
  padding: 18px;
  border: 1px solid #e2e8f0;
  border-radius: 20px;
  background: linear-gradient(180deg, rgba(248, 250, 252, 0.96), rgba(255, 255, 255, 0.88));
}

.question-head {
  display: flex;
  align-items: flex-start;
  gap: 14px;
  margin-bottom: 16px;
}

.q-index {
  width: 40px;
  height: 40px;
  border-radius: 14px;
  display: grid;
  place-items: center;
  background: linear-gradient(135deg, var(--primary), var(--primary-2));
  color: white;
  font-weight: 700;
  flex: 0 0 auto;
}

.q-title { margin: 0; font-size: 18px; }
.q-meta { margin: 8px 0 0; color: var(--muted); line-height: 1.7; font-size: 14px; }

.rating-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 10px;
}

.rating-option {
  padding: 14px;
  border-radius: 16px;
  background: #fff;
  border: 1px solid #dbe4ea;
  cursor: pointer;
  transition: .2s ease;
  display: grid;
  grid-template-columns: auto auto 1fr;
  align-items: start;
  gap: 0 8px;
}


.rating-option:hover {
  transform: translateY(-1px);
  border-color: rgba(15, 118, 110, 0.28);
}

.rating-option input { margin: 3px 2px 0 0; }

.rating-option.active {
  background: linear-gradient(135deg, rgba(15, 118, 110, 0.08), rgba(20, 184, 166, 0.16));
  border-color: rgba(15, 118, 110, 0.35);
}

.rating-value { font-weight: 700; line-height: 1.7; }
.rating-desc { color: var(--muted); font-size: 14px; line-height: 1.7; }

/* ==================== Buttons ==================== */
.actions { display: grid; gap: 12px; }

.submit-status {
  margin: 0;
  color: var(--muted);
  line-height: 1.8;
  font-size: 14px;
}

.primary-btn, .secondary-btn, .ghost-btn {
  width: 100%;
  border: none;
  border-radius: 18px;
  padding: 16px 18px;
  cursor: pointer;
  color: white;
  font-weight: 700;
}

.primary-btn { background: linear-gradient(135deg, var(--primary), var(--primary-2)); }
.secondary-btn { background: linear-gradient(135deg, var(--accent), #2563eb); }
.ghost-btn { background: linear-gradient(135deg, #334155, #0f172a); }

.primary-btn:disabled, .secondary-btn:disabled {
  opacity: 0.5;
  cursor: not-allowed;
}

/* ==================== Student Note ==================== */
.student-note {
  padding: 22px;
  margin-bottom: 22px;
}

.student-note strong { display: block; font-size: 20px; margin-bottom: 8px; }
.student-note p { margin: 6px 0 0; color: var(--muted); line-height: 1.8; }

.mobile-tip { display: none; padding: 18px 22px; margin-bottom: 22px; }
.mobile-tip strong { display: block; font-size: 18px; margin-bottom: 8px; }
.mobile-tip p { margin: 6px 0 0; color: var(--muted); line-height: 1.8; }
.tablet-tip { margin-bottom: 22px; }

/* ==================== Teacher Panel ==================== */
.teacher-panel {
  margin-top: 16px;
  padding: 18px 18px 6px;
  border-radius: 18px;
  background: linear-gradient(180deg, rgba(248, 250, 252, 0.9), rgba(255, 255, 255, 0.84));
}

.panel-head.compact { margin-bottom: 12px; }
.panel-head.compact h3 { margin: 0; font-size: 18px; }

/* ==================== Teacher Data Cards ==================== */
.teacher-data-list { display: grid; gap: 14px; }

.data-card {
  padding: 18px;
  border-radius: 18px;
  border: 1px solid #e2e8f0;
  background: white;
  transition: box-shadow 0.2s;
}

.data-card:hover {
  box-shadow: 0 4px 20px rgba(15, 23, 42, 0.08);
}

.data-card-header {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  gap: 12px;
  margin-bottom: 8px;
}

.data-teacher-name { font-size: 17px; display: block; }
.data-teacher-course { font-size: 13px; color: var(--muted); display: block; margin-top: 2px; }

.data-card-scores {
  display: flex;
  align-items: center;
  gap: 10px;
  flex-shrink: 0;
}

.data-grade-badge {
  padding: 5px 12px;
  border-radius: 999px;
  font-weight: 700;
  font-size: 14px;
}

.grade-A { background: rgba(16, 185, 129, 0.12); color: #059669; }
.grade-B { background: rgba(37, 99, 235, 0.1); color: #2563eb; }
.grade-C { background: rgba(245, 158, 11, 0.12); color: #d97706; }
.grade-D { background: rgba(239, 68, 68, 0.1); color: #dc2626; }

.data-score-num {
  font-weight: 700;
  font-size: 20px;
  color: var(--text);
}

.data-card-meta {
  display: flex;
  gap: 16px;
  font-size: 13px;
  color: var(--muted);
  margin-bottom: 12px;
}

.data-card-answers {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(160px, 1fr));
  gap: 6px;
}

.answer-chip {
  padding: 4px 10px;
  border-radius: 10px;
  font-size: 13px;
  background: #f8fafc;
  border: 1px solid #e2e8f0;
  display: flex;
  justify-content: space-between;
  gap: 8px;
}

.answer-chip-title { color: var(--muted); }
.answer-chip-value { font-weight: 700; }

.answer-chip.val-A { border-color: rgba(16, 185, 129, 0.3); background: rgba(16, 185, 129, 0.04); }
.answer-chip.val-B { border-color: rgba(37, 99, 235, 0.2); background: rgba(37, 99, 235, 0.04); }
.answer-chip.val-C { border-color: rgba(245, 158, 11, 0.2); background: rgba(245, 158, 11, 0.04); }
.answer-chip.val-D { border-color: rgba(239, 68, 68, 0.2); background: rgba(239, 68, 68, 0.04); }

.empty-data {
  text-align: center;
  padding: 48px 24px;
  color: var(--muted);
}

.empty-data .empty-icon { font-size: 48px; display: block; margin-bottom: 16px; }
.empty-data p { margin: 4px 0; line-height: 1.8; }

/* ==================== Ranking List ==================== */
.ranking-list { display: grid; gap: 8px; }

.ranking-item {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 12px 14px;
  border-radius: 14px;
  background: #f8fafc;
  border: 1px solid transparent;
  transition: all 0.2s;
}

.ranking-item:hover {
  background: white;
  border-color: #e2e8f0;
  box-shadow: 0 2px 8px rgba(15, 23, 42, 0.04);
}

.ranking-pos {
  width: 28px;
  height: 28px;
  border-radius: 10px;
  display: grid;
  place-items: center;
  font-weight: 700;
  font-size: 13px;
  background: #e2e8f0;
  color: var(--muted);
  flex-shrink: 0;
}

.ranking-item.pos-1 .ranking-pos { background: #fbbf24; color: #92400e; }
.ranking-item.pos-2 .ranking-pos { background: #c0c0c0; color: #444; }
.ranking-item.pos-3 .ranking-pos { background: #cd7f32; color: #fff; }

.ranking-name {
  flex: 1;
  font-weight: 600;
  font-size: 15px;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.ranking-score {
  font-weight: 700;
  color: var(--primary);
  font-size: 15px;
}

.ranking-meta {
  font-size: 12px;
  color: var(--muted);
  margin-left: 4px;
}

/* ==================== Grade Distribution ==================== */
.grade-dist { display: grid; gap: 10px; }

.grade-bar-row {
  display: flex;
  align-items: center;
  gap: 12px;
}

.grade-bar-label {
  width: 28px;
  font-weight: 700;
  font-size: 15px;
  text-align: center;
}

.grade-bar-track {
  flex: 1;
  height: 22px;
  border-radius: 11px;
  background: #e2e8f0;
  overflow: hidden;
}

.grade-bar-fill {
  height: 100%;
  border-radius: inherit;
  transition: width 0.5s ease;
}

.grade-bar-fill.fill-A { background: linear-gradient(90deg, #10b981, #34d399); }
.grade-bar-fill.fill-B { background: linear-gradient(90deg, #2563eb, #60a5fa); }
.grade-bar-fill.fill-C { background: linear-gradient(90deg, #f59e0b, #fbbf24); }
.grade-bar-fill.fill-D { background: linear-gradient(90deg, #ef4444, #f87171); }

.grade-bar-count {
  width: 50px;
  font-size: 13px;
  color: var(--muted);
  text-align: right;
}

/* ==================== Responsive ==================== */
@media (max-width: 1080px) {
  .hero, .grid-layout, .student-layout, .teacher-layout {
    grid-template-columns: 1fr;
  }
  .hero-stats { grid-template-columns: repeat(2, 1fr); }
  .filter-row { grid-template-columns: 1fr; }
}

@media (max-width: 720px) {
  .app-shell { padding: 12px; }
  .hero, .panel, .actions, .result-card { padding: 16px; }
  .hero { gap: 16px; margin-bottom: 16px; }
  .card { border-radius: 20px; }
  .rating-grid, .hero-stats { grid-template-columns: 1fr; }
  .hero-stats { gap: 10px; }
  .hero-stats div { padding: 14px 12px; }
  .panel-head { flex-direction: column; align-items: flex-start; }
  .rating-option { padding: 12px; }
  .primary-btn, .secondary-btn, .ghost-btn { padding: 15px 16px; }
  .mobile-tip { display: block; }
  .teacher-panel { padding: 14px 14px 4px; }
  .data-card-header { flex-direction: column; }
  .data-card-answers { grid-template-columns: 1fr 1fr; }
  .role-btn { padding: 16px 18px; }
  .role-btn-icon { font-size: 28px; }
}