/* 無人機學習網站 - 淺色質感設計系統 */

:root {
  --bg: #FAFBFC;
  --bg-soft: #F4F6F8;
  --surface: #FFFFFF;
  --border: #E5E7EB;
  --border-soft: #F0F2F5;
  --text: #111827;
  --text-soft: #4B5563;
  --text-mute: #9CA3AF;
  --primary: #0284C7;
  --primary-soft: #E0F2FE;
  --primary-deep: #0C4A6E;
  --accent-amber: #D97706;
  --accent-rose: #E11D48;
  --accent-emerald: #059669;
  --accent-violet: #7C3AED;
  --shadow-sm: 0 1px 2px rgba(15, 23, 42, 0.04);
  --shadow: 0 4px 12px rgba(15, 23, 42, 0.04), 0 1px 3px rgba(15, 23, 42, 0.06);
  --shadow-lg: 0 16px 40px rgba(15, 23, 42, 0.08), 0 4px 12px rgba(15, 23, 42, 0.04);
  --radius: 14px;
  --radius-sm: 8px;
  --radius-lg: 22px;
}

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

html { scroll-behavior: smooth; scroll-padding-top: 80px; }

body {
  font-family: 'Inter', 'Noto Sans TC', -apple-system, BlinkMacSystemFont, 'PingFang TC', 'Microsoft JhengHei', sans-serif;
  font-size: 16px;
  line-height: 1.7;
  color: var(--text);
  background: var(--bg);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  letter-spacing: 0.01em;
}

/* === 導覽列 === */
.nav {
  position: fixed; top: 0; left: 0; right: 0; z-index: 100;
  backdrop-filter: blur(18px) saturate(180%);
  background: rgba(255, 255, 255, 0.78);
  border-bottom: 1px solid var(--border-soft);
  padding: 12px 28px;
  display: flex; align-items: center; justify-content: space-between;
}
.nav-brand {
  display: flex; align-items: center; gap: 10px;
  font-weight: 700; font-size: 17px; color: var(--text);
}
.nav-brand-icon {
  width: 32px; height: 32px; border-radius: 9px;
  background: linear-gradient(135deg, var(--primary) 0%, #38BDF8 100%);
  display: grid; place-items: center;
  color: white; font-size: 16px;
  box-shadow: 0 4px 12px rgba(2, 132, 199, 0.25);
}
.nav-links {
  display: flex; gap: 4px;
  background: var(--bg-soft); padding: 4px; border-radius: 10px;
}
.nav-link {
  padding: 7px 13px; border-radius: 7px;
  font-size: 13px; color: var(--text-soft);
  cursor: pointer; transition: all 0.2s;
  text-decoration: none; user-select: none;
  white-space: nowrap;
}
.nav-link:hover { color: var(--text); background: rgba(255,255,255,0.7); }
.nav-link.active { background: white; color: var(--primary-deep); box-shadow: var(--shadow-sm); font-weight: 600; }
.nav-progress {
  font-size: 12px; color: var(--text-mute);
  display: flex; align-items: center; gap: 8px;
}
.nav-progress-bar {
  width: 80px; height: 6px; border-radius: 3px;
  background: var(--border); overflow: hidden;
}
.nav-progress-fill {
  height: 100%; background: linear-gradient(90deg, var(--primary), #38BDF8);
  width: 0%; transition: width 0.5s ease;
}

/* === Hero === */
.hero {
  padding: 140px 32px 100px;
  max-width: 1200px; margin: 0 auto;
  position: relative;
  text-align: center;
}
.hero-eyebrow {
  display: inline-block;
  padding: 6px 14px;
  background: var(--primary-soft);
  color: var(--primary-deep);
  border-radius: 100px;
  font-size: 13px; font-weight: 500;
  margin-bottom: 24px;
  letter-spacing: 0.04em;
}
.hero h1 {
  font-size: clamp(40px, 6vw, 72px);
  line-height: 1.1; font-weight: 800;
  letter-spacing: -0.03em;
  margin-bottom: 20px;
  background: linear-gradient(135deg, #0F172A 0%, #0284C7 100%);
  -webkit-background-clip: text; background-clip: text;
  color: transparent;
}
.hero p.lead {
  font-size: clamp(17px, 2vw, 21px);
  color: var(--text-soft);
  max-width: 720px; margin: 0 auto 40px;
  line-height: 1.6;
}
.hero-cta {
  display: flex; gap: 14px; justify-content: center; flex-wrap: wrap;
  margin-bottom: 60px;
}
.btn {
  padding: 13px 26px; border-radius: 11px;
  font-size: 14px; font-weight: 600; cursor: pointer;
  border: 1px solid transparent;
  transition: all 0.25s cubic-bezier(0.4, 0, 0.2, 1);
  text-decoration: none; display: inline-flex; align-items: center; gap: 8px;
  letter-spacing: 0.01em;
}
.btn-primary {
  background: var(--primary); color: white;
  box-shadow: 0 4px 14px rgba(2, 132, 199, 0.25);
}
.btn-primary:hover { background: var(--primary-deep); transform: translateY(-2px); box-shadow: 0 8px 20px rgba(2, 132, 199, 0.35); }
.btn-ghost {
  background: white; color: var(--text);
  border-color: var(--border);
}
.btn-ghost:hover { border-color: var(--primary); color: var(--primary); }

.hero-stats {
  display: grid; grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
  gap: 16px; max-width: 760px; margin: 0 auto;
}
.stat {
  background: white; padding: 22px 18px; border-radius: var(--radius);
  border: 1px solid var(--border-soft);
}
.stat-num {
  font-size: 30px; font-weight: 800; letter-spacing: -0.02em;
  background: linear-gradient(135deg, var(--primary), var(--accent-violet));
  -webkit-background-clip: text; background-clip: text; color: transparent;
}
.stat-label { font-size: 12px; color: var(--text-mute); margin-top: 4px; letter-spacing: 0.05em; text-transform: uppercase; }

/* === Section 通用 === */
.section {
  padding: 88px 28px;
  max-width: 1180px; margin: 0 auto;
  scroll-margin-top: 80px;
}
.section-eyebrow {
  display: flex; align-items: center; gap: 12px;
  margin-bottom: 14px;
}
.section-icon {
  width: 44px; height: 44px; border-radius: 12px;
  display: grid; place-items: center; font-size: 22px;
  background: var(--primary-soft); color: var(--primary-deep);
  box-shadow: var(--shadow-sm);
}
.section-meta {
  font-size: 12px; color: var(--text-mute);
  letter-spacing: 0.1em; text-transform: uppercase;
}
.section h2 {
  font-size: clamp(28px, 4vw, 42px);
  font-weight: 800; letter-spacing: -0.02em;
  margin-bottom: 10px; color: var(--text);
}
.section .subtitle {
  font-size: 17px; color: var(--text-soft); margin-bottom: 48px;
}

/* === 知識區塊 === */
.lesson {
  background: white;
  border: 1px solid var(--border-soft);
  border-radius: var(--radius-lg);
  padding: 36px 38px;
  margin-bottom: 24px;
  box-shadow: var(--shadow);
  transition: all 0.3s;
}
.lesson:hover { box-shadow: var(--shadow-lg); transform: translateY(-2px); }
.lesson h3 {
  font-size: 21px; font-weight: 700; color: var(--text);
  margin-bottom: 14px; letter-spacing: -0.01em;
  display: flex; align-items: center; gap: 10px;
}
.lesson h3::before {
  content: ''; width: 4px; height: 20px; border-radius: 2px;
  background: linear-gradient(to bottom, var(--primary), #38BDF8);
}
.lesson p {
  color: var(--text-soft); margin-bottom: 14px; font-size: 15.5px;
}
.lesson p b { color: var(--text); font-weight: 600; }
.lesson .formula {
  background: linear-gradient(135deg, #F8FAFC, #F1F5F9);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 14px 18px; margin: 14px 0;
  font-family: 'SF Mono', 'Monaco', 'Menlo', monospace;
  font-size: 14px; color: var(--primary-deep);
  letter-spacing: 0.02em;
}
.lesson .note {
  background: #FFFBEB; border-left: 3px solid var(--accent-amber);
  padding: 10px 14px; border-radius: 6px;
  font-size: 13.5px; color: #78350F; margin-top: 12px;
}
.lesson .spec {
  background: var(--primary-soft); padding: 8px 12px;
  border-radius: 6px; display: inline-block; margin-top: 8px;
  font-size: 13px; color: var(--primary-deep); font-weight: 500;
}
.lesson ul {
  list-style: none; padding: 0;
}
.lesson ul li {
  padding: 10px 0 10px 28px; position: relative;
  color: var(--text-soft); font-size: 15px;
  border-bottom: 1px dashed var(--border-soft);
}
.lesson ul li:last-child { border-bottom: none; }
.lesson ul li::before {
  content: ''; position: absolute; left: 0; top: 18px;
  width: 16px; height: 2px; background: var(--primary); border-radius: 1px;
}
.lesson table {
  width: 100%; border-collapse: collapse; margin: 14px 0;
  font-size: 14px;
}
.lesson table th, .lesson table td {
  padding: 12px 14px; text-align: left;
  border-bottom: 1px solid var(--border-soft);
}
.lesson table th {
  background: var(--bg-soft); font-weight: 600; color: var(--text);
  font-size: 13px; letter-spacing: 0.02em;
}
.lesson table td { color: var(--text-soft); }

.insight {
  margin-top: 32px; padding: 24px 28px;
  background: linear-gradient(135deg, var(--primary-deep) 0%, #1E40AF 100%);
  color: white; border-radius: var(--radius);
  font-size: 15.5px; line-height: 1.65;
  position: relative; overflow: hidden;
}
.insight::before {
  content: '"'; position: absolute; top: -10px; left: 18px;
  font-size: 90px; font-weight: 800; color: rgba(255,255,255,0.12);
  font-family: Georgia, serif;
}
.insight-label {
  font-size: 11px; letter-spacing: 0.2em; text-transform: uppercase;
  opacity: 0.7; margin-bottom: 8px;
}

/* === 章節導覽 === */
.chapter-nav {
  display: grid; grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 14px; margin-bottom: 60px;
}
.chapter-card {
  background: white; padding: 20px;
  border-radius: var(--radius); border: 1px solid var(--border-soft);
  cursor: pointer; transition: all 0.25s;
  text-decoration: none; color: inherit;
}
.chapter-card:hover {
  border-color: var(--primary); transform: translateY(-3px);
  box-shadow: var(--shadow-lg);
}
.chapter-card-icon { font-size: 28px; margin-bottom: 10px; }
.chapter-card-title { font-weight: 700; font-size: 15px; margin-bottom: 4px; }
.chapter-card-sub { font-size: 12px; color: var(--text-mute); }

/* === PID 模擬器 === */
.simulator {
  background: white; border: 1px solid var(--border-soft);
  border-radius: var(--radius-lg); padding: 32px;
  box-shadow: var(--shadow); margin-top: 32px;
}
.simulator-header {
  display: flex; justify-content: space-between; align-items: flex-start;
  margin-bottom: 24px;
}
.simulator-title { font-size: 18px; font-weight: 700; }
.simulator-desc { font-size: 13px; color: var(--text-mute); margin-top: 4px; }

.sim-canvas-wrap {
  background: linear-gradient(180deg, #F0F9FF 0%, #E0F2FE 100%);
  border-radius: var(--radius); padding: 16px;
  position: relative; overflow: hidden;
}
.sim-canvas { display: block; width: 100%; height: 280px; }

.sim-controls {
  margin-top: 24px; display: grid; grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
  gap: 18px;
}
.slider-group label {
  display: flex; justify-content: space-between; align-items: center;
  font-size: 13px; color: var(--text-soft); margin-bottom: 6px; font-weight: 500;
}
.slider-group label b {
  font-family: 'SF Mono', monospace; color: var(--primary-deep); font-weight: 600;
}
.slider {
  -webkit-appearance: none; appearance: none;
  width: 100%; height: 5px; border-radius: 3px;
  background: linear-gradient(90deg, var(--primary-soft), var(--primary));
  outline: none;
}
.slider::-webkit-slider-thumb {
  -webkit-appearance: none; appearance: none;
  width: 18px; height: 18px; border-radius: 50%;
  background: white; border: 2px solid var(--primary);
  cursor: pointer; box-shadow: 0 2px 6px rgba(2,132,199,0.3);
}
.sim-buttons {
  margin-top: 20px; display: flex; gap: 10px; flex-wrap: wrap;
}
.sim-btn {
  padding: 8px 16px; border-radius: 8px; font-size: 13px;
  background: var(--bg-soft); border: 1px solid var(--border);
  cursor: pointer; transition: all 0.2s; font-weight: 500;
  color: var(--text-soft);
}
.sim-btn:hover { background: white; border-color: var(--primary); color: var(--primary); }
.sim-btn.active { background: var(--primary); color: white; border-color: var(--primary); }

.sim-readout {
  display: grid; grid-template-columns: repeat(3, 1fr); gap: 12px;
  margin-top: 16px; padding-top: 16px; border-top: 1px solid var(--border-soft);
}
.sim-readout-item {
  background: var(--bg-soft); padding: 10px 14px; border-radius: 8px;
}
.sim-readout-label { font-size: 11px; color: var(--text-mute); text-transform: uppercase; letter-spacing: 0.1em; }
.sim-readout-value { font-size: 18px; font-weight: 700; color: var(--text); margin-top: 2px; font-family: 'SF Mono', monospace; }

/* === 法規查詢 === */
.region-tabs {
  display: flex; gap: 8px; flex-wrap: wrap;
  margin-bottom: 20px;
}
.region-tab {
  padding: 12px 20px; border-radius: 12px;
  background: white; border: 1px solid var(--border);
  cursor: pointer; font-weight: 600; font-size: 14px;
  transition: all 0.2s;
}
.region-tab:hover { border-color: var(--primary); }
.region-tab.active { background: var(--primary); color: white; border-color: var(--primary); }

.regulation-card {
  background: white; border: 1px solid var(--border-soft);
  border-radius: var(--radius-lg); padding: 32px;
  box-shadow: var(--shadow);
}
.reg-summary {
  display: grid; grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
  gap: 16px; margin-bottom: 24px;
}
.reg-summary-item {
  padding: 14px 16px; background: var(--bg-soft); border-radius: var(--radius);
}
.reg-summary-label { font-size: 11px; color: var(--text-mute); text-transform: uppercase; letter-spacing: 0.08em; }
.reg-summary-value { font-size: 15px; font-weight: 600; margin-top: 4px; }

/* === 題庫 === */
.quiz-container {
  background: white; border: 1px solid var(--border-soft);
  border-radius: var(--radius-lg); padding: 36px;
  box-shadow: var(--shadow); max-width: 760px; margin: 0 auto;
}
.quiz-progress {
  display: flex; justify-content: space-between; align-items: center;
  margin-bottom: 22px; padding-bottom: 18px; border-bottom: 1px solid var(--border-soft);
}
.quiz-counter { font-size: 13px; color: var(--text-mute); letter-spacing: 0.05em; }
.quiz-score { font-size: 13px; font-weight: 600; color: var(--primary-deep); }
.quiz-progress-bar { height: 4px; background: var(--border); border-radius: 2px; overflow: hidden; margin-top: 10px; }
.quiz-progress-fill { height: 100%; background: var(--primary); transition: width 0.4s; }

.quiz-question {
  font-size: 18px; font-weight: 600; line-height: 1.55;
  margin: 24px 0 22px; color: var(--text);
}
.quiz-options {
  display: flex; flex-direction: column; gap: 10px;
}
.quiz-option {
  padding: 14px 18px; border-radius: 11px;
  background: var(--bg-soft); border: 2px solid transparent;
  cursor: pointer; font-size: 14.5px; color: var(--text);
  transition: all 0.2s; text-align: left;
  display: flex; align-items: center; gap: 12px;
}
.quiz-option:hover { background: var(--primary-soft); border-color: var(--primary); }
.quiz-option-letter {
  width: 26px; height: 26px; border-radius: 7px;
  background: white; display: grid; place-items: center;
  font-size: 12px; font-weight: 700; color: var(--text-soft);
  flex-shrink: 0;
}
.quiz-option.correct { background: #ECFDF5; border-color: var(--accent-emerald); color: #064E3B; }
.quiz-option.correct .quiz-option-letter { background: var(--accent-emerald); color: white; }
.quiz-option.wrong { background: #FEF2F2; border-color: var(--accent-rose); color: #7F1D1D; }
.quiz-option.wrong .quiz-option-letter { background: var(--accent-rose); color: white; }
.quiz-option:disabled { cursor: default; }

.quiz-explanation {
  margin-top: 20px; padding: 16px 18px;
  background: linear-gradient(135deg, #F0F9FF, #E0F2FE);
  border-radius: var(--radius);
  font-size: 14px; color: var(--primary-deep); line-height: 1.6;
  border-left: 3px solid var(--primary);
}

.quiz-actions {
  margin-top: 20px; display: flex; gap: 12px; justify-content: space-between;
}

.quiz-result {
  text-align: center; padding: 30px 20px;
}
.quiz-result-score {
  font-size: 64px; font-weight: 800;
  background: linear-gradient(135deg, var(--primary), var(--accent-violet));
  -webkit-background-clip: text; background-clip: text; color: transparent;
}
.quiz-result-text { font-size: 16px; color: var(--text-soft); margin-top: 8px; }

/* === 路徑追蹤 === */
.roadmap {
  display: flex; flex-direction: column; gap: 18px; margin-top: 32px;
}
.roadmap-stage {
  background: white; border: 1px solid var(--border-soft);
  border-radius: var(--radius-lg); padding: 26px 30px;
  box-shadow: var(--shadow); position: relative;
  border-left: 4px solid var(--border);
  transition: all 0.3s;
}
.roadmap-stage.completed { border-left-color: var(--accent-emerald); background: #FAFFFE; }
.roadmap-stage.in-progress { border-left-color: var(--primary); }
.roadmap-stage-head {
  display: flex; justify-content: space-between; align-items: center;
  margin-bottom: 16px;
}
.roadmap-stage-title { font-size: 18px; font-weight: 700; }
.roadmap-stage-week { font-size: 13px; color: var(--text-mute); }
.roadmap-goals { display: flex; flex-direction: column; gap: 8px; }
.roadmap-goal {
  display: flex; align-items: center; gap: 12px;
  padding: 8px 0; cursor: pointer;
  font-size: 14.5px; color: var(--text-soft);
}
.roadmap-goal-check {
  width: 22px; height: 22px; border-radius: 6px;
  border: 2px solid var(--border);
  display: grid; place-items: center;
  flex-shrink: 0; transition: all 0.2s;
  background: white;
}
.roadmap-goal.checked .roadmap-goal-check {
  background: var(--accent-emerald); border-color: var(--accent-emerald); color: white;
}
.roadmap-goal.checked .roadmap-goal-check::after { content: '✓'; font-size: 13px; font-weight: 700; }
.roadmap-goal.checked { color: var(--text-mute); text-decoration: line-through; }
.roadmap-progress {
  margin-top: 16px; padding-top: 16px;
  border-top: 1px dashed var(--border-soft);
  font-size: 12px; color: var(--text-mute);
  display: flex; align-items: center; gap: 10px;
}
.roadmap-progress-bar { flex: 1; height: 5px; background: var(--border); border-radius: 3px; overflow: hidden; }
.roadmap-progress-fill { height: 100%; background: linear-gradient(90deg, var(--primary), var(--accent-emerald)); transition: width 0.4s; }

/* === ROI 計算器 === */
.calculator {
  background: white; border: 1px solid var(--border-soft);
  border-radius: var(--radius-lg); padding: 32px;
  box-shadow: var(--shadow); margin-top: 24px;
}
.calc-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 32px; }
@media (max-width: 720px) { .calc-grid { grid-template-columns: 1fr; } }
.calc-input {
  display: flex; flex-direction: column; gap: 14px;
}
.calc-input label {
  display: flex; flex-direction: column; gap: 6px;
  font-size: 13px; color: var(--text-soft); font-weight: 500;
}
.calc-input input, .calc-input select {
  padding: 11px 14px; border-radius: 10px;
  border: 1px solid var(--border); background: var(--bg-soft);
  font-size: 14px; color: var(--text);
  font-family: inherit;
}
.calc-input input:focus, .calc-input select:focus {
  outline: none; border-color: var(--primary); background: white;
}
.calc-output {
  background: linear-gradient(135deg, #F0F9FF, #E0F2FE);
  border-radius: var(--radius); padding: 24px;
  display: flex; flex-direction: column; justify-content: center;
}
.calc-result-row {
  display: flex; justify-content: space-between;
  padding: 10px 0; border-bottom: 1px dashed rgba(2,132,199,0.2);
  font-size: 14px;
}
.calc-result-row:last-child { border-bottom: none; }
.calc-result-row b { font-family: 'SF Mono', monospace; color: var(--primary-deep); }
.calc-bottom-line {
  margin-top: 14px; padding: 14px;
  background: white; border-radius: 10px;
  font-size: 13px; color: var(--text-soft);
  border-left: 3px solid var(--accent-emerald);
}

/* === 產業地圖 === */
.industry-map {
  background: linear-gradient(180deg, #F8FAFC 0%, #F1F5F9 100%);
  border: 1px solid var(--border-soft);
  border-radius: var(--radius-lg); padding: 24px;
  position: relative; min-height: 480px;
  box-shadow: var(--shadow);
}
.industry-tier-label {
  position: absolute; left: 20px; font-size: 11px;
  text-transform: uppercase; letter-spacing: 0.2em;
  color: var(--text-mute); font-weight: 600;
}
.industry-node {
  position: absolute; transform: translate(-50%, -50%);
  background: white; padding: 8px 12px;
  border-radius: 100px; border: 2px solid var(--border);
  font-size: 12px; font-weight: 600; cursor: pointer;
  transition: all 0.25s; white-space: nowrap;
  box-shadow: var(--shadow-sm);
}
.industry-node:hover {
  border-color: var(--primary); transform: translate(-50%, -50%) scale(1.08);
  box-shadow: var(--shadow);
  z-index: 10;
}
.industry-node.upstream { color: var(--accent-amber); }
.industry-node.midstream { color: var(--primary-deep); border-color: var(--primary-soft); }
.industry-node.downstream { color: var(--accent-emerald); }
.industry-tooltip {
  position: absolute; background: var(--text);
  color: white; padding: 10px 14px; border-radius: 8px;
  font-size: 12px; white-space: nowrap; z-index: 50;
  pointer-events: none; opacity: 0; transition: opacity 0.2s;
  transform: translate(-50%, -120%); top: 0; left: 50%;
}
.industry-node:hover .industry-tooltip { opacity: 1; }

/* === 搖桿模擬器 === */
.joystick-demo {
  display: grid; grid-template-columns: 1fr 1fr; gap: 24px;
  margin-top: 24px;
}
@media (max-width: 720px) { .joystick-demo { grid-template-columns: 1fr; } }
.joystick {
  background: linear-gradient(135deg, #1E293B, #0F172A);
  border-radius: var(--radius-lg);
  aspect-ratio: 1; max-width: 220px; margin: 0 auto;
  position: relative; cursor: pointer;
  box-shadow: inset 0 4px 12px rgba(0,0,0,0.4), 0 4px 12px rgba(0,0,0,0.15);
}
.joystick-center {
  position: absolute; top: 50%; left: 50%;
  width: 14px; height: 14px; border-radius: 50%;
  background: rgba(255,255,255,0.15); transform: translate(-50%,-50%);
}
.joystick-knob {
  position: absolute; top: 50%; left: 50%;
  width: 60px; height: 60px; border-radius: 50%;
  background: linear-gradient(135deg, #38BDF8, var(--primary));
  transform: translate(-50%,-50%);
  box-shadow: 0 4px 14px rgba(56, 189, 248, 0.5);
  cursor: grab; transition: transform 0.05s;
}
.joystick-label {
  text-align: center; margin-bottom: 12px;
  font-size: 13px; color: var(--text-soft); font-weight: 600;
}
.joystick-readout {
  text-align: center; margin-top: 12px;
  font-family: 'SF Mono', monospace; font-size: 12px;
  color: var(--text-mute);
}

/* === Footer === */
.footer {
  border-top: 1px solid var(--border-soft);
  padding: 40px 32px;
  text-align: center; color: var(--text-mute);
  font-size: 13px;
  background: var(--bg-soft);
  margin-top: 80px;
}
.footer a { color: var(--primary); text-decoration: none; }

/* === 響應式 === */
@media (max-width: 768px) {
  .nav { padding: 10px 16px; flex-wrap: wrap; gap: 10px; }
  .nav-links { order: 3; width: 100%; overflow-x: auto; }
  .hero { padding: 110px 20px 60px; }
  .section { padding: 60px 20px; }
  .lesson { padding: 24px 20px; }
}

/* === 微動畫 === */
@keyframes fadeUp {
  from { opacity: 0; transform: translateY(12px); }
  to { opacity: 1; transform: translateY(0); }
}
.lesson, .section h2, .chapter-card { animation: fadeUp 0.5s ease backwards; }

/* === 飛行軌跡視覺 === */
.physics-viz {
  background: linear-gradient(180deg, #FFFFFF, #F8FAFC);
  border: 1px solid var(--border-soft);
  border-radius: var(--radius); padding: 20px;
  margin-top: 14px;
}
.physics-viz svg { width: 100%; max-width: 500px; display: block; margin: 0 auto; }

/* === v1.2 新手認知友善元素 === */
.analogy-box {
  background: linear-gradient(135deg, #FAF5FF, #F3E8FF);
  border-left: 3px solid var(--accent-violet);
  padding: 12px 16px; border-radius: 8px;
  font-size: 14px; color: #5B21B6; margin-bottom: 14px;
  line-height: 1.65;
}

.sim-narration {
  background: linear-gradient(135deg, #FFFBEB, #FEF3C7);
  border-left: 4px solid var(--accent-amber);
  padding: 16px 20px; border-radius: 12px;
  margin-top: 18px;
  font-size: 14px; line-height: 1.7;
  color: #78350F;
}

.sim-diagnosis {
  background: white; border: 2px dashed var(--primary);
  padding: 14px 18px; border-radius: 12px;
  margin-top: 14px; font-size: 14px;
  color: var(--primary-deep);
}

/* 課程推薦卡 */
.course-card {
  background: linear-gradient(135deg, #0C4A6E 0%, #1E40AF 100%);
  color: white; padding: 32px;
  border-radius: var(--radius-lg);
  box-shadow: 0 20px 50px rgba(12, 74, 110, 0.25);
  margin-top: 24px;
  position: relative; overflow: hidden;
}
.course-card::before {
  content: ''; position: absolute; top: -50%; right: -10%;
  width: 400px; height: 400px;
  background: radial-gradient(circle, rgba(255,255,255,0.08) 0%, transparent 70%);
  border-radius: 50%;
}
.course-badge {
  display: inline-block; padding: 5px 12px;
  background: rgba(255,255,255,0.18); backdrop-filter: blur(8px);
  border-radius: 100px; font-size: 12px;
  letter-spacing: 0.1em; margin-bottom: 14px;
}
.course-title { font-size: 24px; font-weight: 800; margin-bottom: 12px; line-height: 1.3; }
.course-org { font-size: 14px; opacity: 0.85; margin-bottom: 24px; }
.course-meta {
  display: grid; grid-template-columns: repeat(auto-fit, minmax(140px, 1fr));
  gap: 14px; margin-bottom: 24px;
}
.course-meta-item {
  background: rgba(255,255,255,0.1); padding: 12px 14px;
  border-radius: 10px;
}
.course-meta-label { font-size: 11px; opacity: 0.7; text-transform: uppercase; letter-spacing: 0.1em; }
.course-meta-value { font-size: 14px; font-weight: 600; margin-top: 4px; }
.course-fee { font-size: 32px; font-weight: 800; }
.course-syllabus {
  background: rgba(255,255,255,0.06); padding: 16px;
  border-radius: 12px; margin-top: 16px;
  font-size: 13px;
}
.course-syllabus-day {
  font-weight: 700; margin-bottom: 8px;
  letter-spacing: 0.1em; opacity: 0.9;
}
.course-syllabus-item {
  display: flex; gap: 10px; padding: 6px 0;
  border-bottom: 1px dashed rgba(255,255,255,0.12);
}
.course-syllabus-item:last-child { border-bottom: none; }
.course-syllabus-time { font-family: 'SF Mono', monospace; font-size: 11px; min-width: 90px; opacity: 0.7; }
.course-syllabus-topic { font-weight: 600; min-width: 130px; }
.course-syllabus-detail { opacity: 0.75; font-size: 12px; }
.course-cta {
  display: inline-flex; align-items: center; gap: 8px;
  margin-top: 20px; padding: 12px 22px;
  background: white; color: #0C4A6E;
  border-radius: 10px; text-decoration: none;
  font-weight: 700; font-size: 14px;
  transition: transform 0.2s;
}
.course-cta:hover { transform: translateY(-2px); }

/* 新手導向頁首 banner */
.beginner-banner {
  background: linear-gradient(135deg, #ECFDF5, #D1FAE5);
  border: 1px solid #6EE7B7; border-radius: var(--radius-lg);
  padding: 24px 28px; margin-bottom: 32px;
}
.beginner-banner-title {
  font-size: 18px; font-weight: 700;
  color: #064E3B; margin-bottom: 8px;
  display: flex; align-items: center; gap: 10px;
}
.beginner-banner-text { font-size: 14px; color: #065F46; line-height: 1.7; }

/* PID slider 加 tooltip 提示 */
.slider-tooltip {
  font-size: 11px; color: var(--text-mute);
  margin-top: 4px; line-height: 1.5;
}

/* 數字徽章 */
.text-xs { font-size: 11px; opacity: 0.7; }

/* === 進階教材 CH15-18 工程計算機 === */
.eng-calc {
  background: linear-gradient(135deg, #FFFFFF, #F8FAFC);
  border: 1.5px solid var(--border);
  border-radius: 14px;
  padding: 22px 24px;
  margin-bottom: 18px;
  box-shadow: var(--shadow-sm);
}
.eng-calc-head {
  border-bottom: 2px solid var(--primary-soft);
  padding-bottom: 10px;
  margin-bottom: 14px;
}
.eng-calc-title {
  font-size: 17px; font-weight: 700;
  color: var(--primary-deep);
}
.eng-calc-sub {
  font-size: 12px; color: var(--text-soft);
  margin-top: 2px;
}
.eng-calc-body {
  display: grid; grid-template-columns: 1fr 1fr; gap: 18px;
}
@media (max-width: 720px) { .eng-calc-body { grid-template-columns: 1fr; } }
.eng-calc-inputs { display: flex; flex-direction: column; gap: 10px; }
.eng-input-row {
  display: grid; grid-template-columns: 130px 1fr 80px;
  gap: 10px; align-items: center;
  font-size: 13px;
}
.eng-input-row label { color: var(--text-soft); font-weight: 500; }
.eng-input-row input[type=range] {
  -webkit-appearance: none; appearance: none;
  width: 100%; height: 5px;
  background: var(--border); border-radius: 3px;
  outline: none;
}
.eng-input-row input[type=range]::-webkit-slider-thumb {
  -webkit-appearance: none; appearance: none;
  width: 16px; height: 16px;
  background: var(--primary); border-radius: 50%;
  cursor: pointer;
}
.eng-input-row output {
  font-family: 'SF Mono', 'Monaco', monospace;
  font-size: 12px; color: var(--primary-deep);
  font-weight: 700; text-align: right;
}
.eng-calc-result {
  background: linear-gradient(135deg, #F0F9FF, #E0F2FE);
  border-radius: 10px; padding: 14px 16px;
  border-left: 3px solid var(--primary);
}
.eng-row {
  display: flex; justify-content: space-between;
  padding: 6px 0; font-size: 13px;
  border-bottom: 1px dashed rgba(2, 132, 199, 0.15);
}
.eng-row:last-child { border: none; padding-top: 8px; font-weight: 700; }
.eng-key { color: var(--text-soft); }
.eng-val { font-family: 'SF Mono', monospace; color: var(--primary-deep); font-weight: 600; }

/* 預習進度卡 */
.prep-tracker {
  background: linear-gradient(135deg, #FFFFFF 0%, #F0F9FF 100%);
  border: 1px solid var(--border-soft);
  border-radius: var(--radius-lg);
  padding: 36px 40px;
  box-shadow: var(--shadow);
}
.prep-eyebrow {
  display: inline-block;
  background: var(--primary-soft); color: var(--primary-deep);
  padding: 4px 12px; border-radius: 100px;
  font-size: 12px; font-weight: 600; letter-spacing: 0.05em;
  margin-bottom: 12px;
}
.prep-title {
  font-size: 24px; font-weight: 800; letter-spacing: -0.02em;
  margin-bottom: 10px;
}
.prep-subtitle {
  font-size: 14.5px; color: var(--text-soft); line-height: 1.7;
  max-width: 720px;
}
.prep-grid {
  display: grid; grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 12px; margin-top: 24px;
}
.prep-card {
  background: white; border: 1px solid var(--border);
  border-radius: 12px; padding: 16px;
  text-decoration: none; color: inherit;
  transition: all 0.25s; cursor: pointer;
  display: block;
}
.prep-card:hover {
  border-color: var(--primary); transform: translateY(-3px);
  box-shadow: var(--shadow);
}
.prep-card.done {
  background: linear-gradient(135deg, #ECFDF5, #D1FAE5);
  border-color: var(--accent-emerald);
}
.prep-card-tag {
  font-size: 10px; font-weight: 700; color: var(--text-mute);
  letter-spacing: 0.1em; margin-bottom: 6px;
}
.prep-card-title { font-size: 14px; font-weight: 700; margin-bottom: 8px; }
.prep-card-check {
  font-size: 12px; color: var(--primary);
  font-weight: 600;
}
.prep-card.done .prep-card-check { color: var(--accent-emerald); }

/* 無障礙：尊重 reduced-motion 設定 */
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }
}