:root {
      --primary-green: #4CAF50;
      --secondary-green: #C8E6C9;
      --accent-yellow: #FFD54F;
      --bg-color: #F4F9F4;
      --card-bg: #FFFFFF;
      --text-dark: #2C3E50;
      --env-theme-bg: #F4F9F4;
    }

    * {
      box-sizing: border-box;
      font-family: "Noto Sans TC", "PingFang HK", "Microsoft JhengHei", "Helvetica Neue", sans-serif;
      margin: 0;
      padding: 0;
    }

    body {
      background-color: var(--env-theme-bg);
      color: var(--text-dark);
      display: flex;
      flex-direction: column;
      align-items: center;
      min-height: 100vh;
      transition: background-color 1s ease;
    }

    header {
      width: 100%;
      background-color: var(--primary-green);
      display: flex;
      justify-content: center;
      gap: 20px;
      padding: 15px 0;
      box-shadow: 0 4px 12px rgba(0,0,0,0.08);
      z-index: 10;
    }

    .nav-btn {
      background: transparent;
      border: 2px solid white;
      color: white;
      padding: 8px 22px;
      font-size: 1rem;
      border-radius: 25px;
      cursor: pointer;
      font-weight: bold;
      transition: all 0.3s;
    }

    .nav-btn.active, .nav-btn:hover {
      background-color: white;
      color: var(--primary-green);
    }
    .nav-btn:disabled {
      opacity: 0.55;
      cursor: not-allowed;
    }

    .container {
      width: 95%;
      max-width: 1250px;
      margin: 20px auto;
      flex-grow: 1;
      background-color: var(--env-theme-bg);
    }

    .page {
      display: none;
    }

    .page.active {
      display: block;
    }

    .story-layout {
      display: flex;
      flex-direction: column;
      gap: 20px;
    }
    @media (min-width: 768px) {
      .story-layout { display: grid; grid-template-columns: 1fr 1fr; }
    }
    .progress-bar-container {
      width: 100%; background-color: #E0E0E0; border-radius: 10px; height: 12px; margin-bottom: 15px; overflow: hidden;
    }
    .progress-bar { height: 100%; width: 20%; background-color: var(--primary-green); transition: width 0.4s ease; }
    .plant-stage {
      background-color: var(--card-bg); border-radius: 25px; padding: 20px; display: flex; flex-direction: column; align-items: center; justify-content: center; min-height: 320px; box-shadow: 0 6px 18px rgba(0,0,0,0.05);
    }
    .plant-svg-story { width: 180px; height: 220px; transition: all 0.5s ease; }
    .dialogue-box {
      background-color: var(--card-bg); border-radius: 25px; padding: 25px; box-shadow: 0 6px 18px rgba(0,0,0,0.05); display: flex; flex-direction: column; justify-content: space-between;
    }
    .speaker-name { font-weight: bold; font-size: 1.3rem; margin-bottom: 10px; text-align: center; }
    .dialogue-text { font-size: 1.1rem; line-height: 1.6; min-height: 80px; margin-bottom: 20px; text-align: center;}
    .options-container { display: flex; flex-direction: column; gap: 10px; }
    .option-btn { background-color: #F9F9F9; border: 2px solid var(--secondary-green); border-radius: 15px; padding: 12px 15px; font-size: 1rem; cursor: pointer; transition: all 0.2s; text-align: left; font-weight: bold;}
    .option-btn:hover { background-color: var(--secondary-green); }

    .sensor-header {
      background: white;
      padding: 15px 20px;
      border-radius: 20px;
      margin-bottom: 20px;
      box-shadow: 0 4px 12px rgba(0,0,0,0.05);
      display: flex;
      gap: 10px;
      flex-wrap: wrap;
    }
    .sensor-header input[type="text"] {
      flex: 1; min-width: 250px; padding: 12px; border: 2px solid #E0E0E0; border-radius: 12px; font-size: 0.95rem; outline: none;
    }
    .sensor-header button {
      background: var(--primary-green); color: white; border: none; padding: 12px 20px; border-radius: 12px; cursor: pointer; font-weight: bold; font-size: 0.95rem;
    }
    .sensor-header button:disabled, .mic-btn:disabled {
      opacity: 0.55;
      cursor: not-allowed;
      box-shadow: none;
    }
    .sync-status-panel {
      width: 100%;
      display: grid;
      grid-template-columns: repeat(auto-fit, minmax(190px, 1fr));
      gap: 10px;
      margin-top: 4px;
    }
    .status-pill {
      background: #F6FBF6;
      border: 2px solid var(--secondary-green);
      border-radius: 14px;
      padding: 10px 12px;
      font-size: 1rem;
      font-weight: 800;
      text-align: center;
    }
    .status-pill strong {
      color: var(--primary-green);
    }
    .status-pill.error {
      background: #FFF5F5;
      border-color: #FF8A80;
      color: #B71C1C;
    }
    .status-pill.warn {
      background: #FFFDE7;
      border-color: #FFD54F;
      color: #795548;
    }

    .ai-chat-panel {
      background: #F4F1FF;
      border: 3px solid #9575CD;
      border-radius: 20px;
      padding: 15px 20px;
      margin-bottom: 20px;
      box-shadow: 0 4px 12px rgba(92, 107, 192, 0.12);
      display: grid;
      grid-template-columns: repeat(auto-fit, minmax(210px, 1fr));
      gap: 10px;
      align-items: end;
    }
    .ai-chat-panel h2,
    .ai-chat-panel .status-pill {
      grid-column: 1 / -1;
      margin: 0;
    }
    .ai-chat-panel h2 {
      color: #5E35B1;
      font-size: 1.2rem;
      text-align: center;
    }
    .ai-chat-intro {
      grid-column: 1 / -1;
      margin: 0;
      color: #5E35B1;
      font-weight: 700;
      text-align: center;
      line-height: 1.45;
    }
    .ai-setting {
      display: flex;
      align-items: center;
      gap: 8px;
      font-weight: 800;
      color: #4527A0;
      white-space: nowrap;
    }
    .ai-setting input,
    .ai-setting select {
      flex: 1;
      min-height: 44px;
      min-width: 0;
      padding: 10px 12px;
      border: 2px solid #D1C4E9;
      border-radius: 10px;
      background: #FFFFFF;
      color: #263238;
      font: inherit;
    }
    .ai-key-field {
      grid-column: 1 / -1;
    }
    .ai-key-row {
      display: flex;
      flex: 1;
      min-width: 0;
      gap: 8px;
      align-items: stretch;
    }
    .ai-key-row input {
      flex: 1;
      min-width: 0;
    }
  
    .ai-key-actions {
      display: flex;
      gap: 10px;
      flex-wrap: nowrap;
    }
    .ai-key-actions button {
      flex: 1;
      white-space: nowrap;
    }

    .ai-chat-panel button {
      min-height: 44px;
      padding: 10px 14px;
      border: none;
      border-radius: 10px;
      background: #5E35B1;
      color: #FFFFFF;
      font: inherit;
      font-weight: 800;
      cursor: pointer;
    }
    .ai-chat-panel .ai-small-btn {
      min-width: 52px;
      padding: 10px 12px;
      background: #7E57C2;
    }
    .ai-chat-panel .ai-secondary-btn {
      background: #EDE7F6;
      color: #4527A0;
      border: 2px solid #B39DDB;
    }
    .ai-chat-panel button:hover { background: #4527A0; }
    .ai-chat-panel .ai-secondary-btn:hover { background: #D1C4E9; }
    .ai-chat-panel button:disabled { opacity: 0.55; cursor: not-allowed; }

    .mock-panel {
      background: rgba(255, 255, 255, 0.95);
      border: 3px dashed var(--primary-green);
      border-radius: 20px;
      padding: 15px 20px;
      margin-bottom: 25px;
      display: flex;
      gap: 20px;
      align-items: center;
      justify-content: space-around;
      flex-wrap: wrap;
    }
    .mock-group {
      display: flex;
      align-items: center;
      gap: 8px;
      font-size: 1rem;
      font-weight: bold;
    }

    .dashboard-grid {
      display: grid;
      grid-template-columns: 1fr;
      gap: 25px;
      align-items: stretch;
    }
    @media (min-width: 950px) {
      .dashboard-grid {
        grid-template-columns: 1fr 1.2fr 1fr;
      }
    }

    @keyframes breathe {
      0%, 100% { transform: translateY(0) scale(1); }
      50% { transform: translateY(-4px) scale(1.015); }
    }

    .thermometer-card {
      background: #FFF0F0;
      border: 5px solid #FF8A80;
      border-radius: 35px;
      padding: 25px 20px;
      box-shadow: 0 10px 25px rgba(255, 138, 128, 0.2);
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: space-between;
      min-height: 560px;
      animation: breathe 4s infinite ease-in-out;
    }
    .thermometer-card .speaker-name { color: #D32F2F; }

    .thermo-svg-container {
      width: 180px;
      height: 420px;
      position: relative;
    }

    .plant-center-card {
      background: #E8F5E9;
      border: 5px solid #81C784;
      border-radius: 35px;
      padding: 25px 20px;
      box-shadow: 0 10px 25px rgba(129, 199, 132, 0.2);
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: space-between;
      min-height: 560px;
      animation: breathe 4.5s infinite ease-in-out 0.4s;
    }
    .plant-center-card .speaker-name { color: #2E7D32; }

    .sway-anim { animation: sway 3s infinite ease-in-out; }
    .sweat-anim { animation: sweat 1.2s infinite ease-in-out; }
    .shiver-anim { animation: shiver 0.25s infinite ease-in-out; }

    @keyframes sway {
      0%, 100% { transform: rotate(0deg); }
      50% { transform: rotate(5deg); }
    }
    @keyframes sweat {
      0%, 100% { transform: translateY(0); }
      50% { transform: translateY(6px); }
    }
    @keyframes shiver {
      0% { transform: translate(0, 0); }
      50% { transform: translate(-4px, 2px); }
      100% { transform: translate(4px, -2px); }
    }

    .humidity-card {
      background: #E1F5FE;
      border: 5px solid #4FC3F7;
      border-radius: 35px;
      padding: 25px 20px;
      box-shadow: 0 10px 25px rgba(79, 195, 247, 0.2);
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: flex-start;
      min-height: 560px;
      animation: breathe 4.2s infinite ease-in-out 0.8s;
    }
    .humidity-card .speaker-name { color: #0288D1; }

    .humidity-card-body {
      flex: 1;
      display: flex;
      align-items: center;
      justify-content: center;
      width: 100%;
    }

    .hydrometer-svg {
      width: 210px;
      height: 294px;
    }



    .voice-control {
      display: flex;
      flex-direction: column;
      align-items: center;
      gap: 6px;
    }
    .mic-btn {
      width: 60px; height: 60px; border-radius: 50%; background: var(--primary-green); border: none; color: white; font-size: 1.5rem; cursor: pointer; box-shadow: 0 4px 12px rgba(0,0,0,0.15); transition: all 0.3s;
    }
    .hidden-stage { display: none; }
    .mic-btn.listening { background: #FF5252; animation: pulse 1.5s infinite; }
    @keyframes pulse { 0% { transform: scale(1); } 50% { transform: scale(1.1); } 100% { transform: scale(1); } }

    .ai-layout {
      display: grid;
      grid-template-columns: 1fr;
      gap: 16px;
      align-items: stretch;
    }
    @media (min-width: 950px) {
      .ai-layout {
        grid-template-columns: 1fr 1.1fr;
      }
    }
    .vision-card {
      background: #F3F7FF;
      border: 5px solid #5C6BC0;
      border-radius: 24px;
      padding: 16px;
      box-shadow: 0 10px 25px rgba(92, 107, 192, 0.18);
      display: flex;
      flex-direction: column;
      gap: 10px;
      min-height: 0;
    }
    .vision-card .speaker-name { color: #3949AB; }
    .vision-controls {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 10px;
    }
    .file-picker-label {
      grid-column: 1 / -1;
      background: white;
      border: 2px dashed #9FA8DA;
      border-radius: 14px;
      padding: 12px;
      font-size: 1rem;
      font-weight: bold;
      cursor: pointer;
      color: var(--text-dark);
    }
    .file-picker-label span {
      color: #3949AB;
    }
    .vision-controls input[type="file"] {
      display: none;
    }
    .vision-controls button {
      background: #5C6BC0;
      color: white;
      border: none;
      padding: 13px 16px;
      border-radius: 14px;
      cursor: pointer;
      font-size: 1rem;
      font-weight: bold;
    }
    .vision-controls button:disabled {
      opacity: 0.55;
      cursor: not-allowed;
    }
    .webcam-frame {
      width: 100%;
      aspect-ratio: 16 / 9;
      max-height: 260px;
      background: #111827;
      border: 4px solid #C5CAE9;
      border-radius: 22px;
      overflow: hidden;
      display: flex;
      align-items: center;
      justify-content: center;
      color: white;
      font-weight: bold;
      text-align: center;
    }
    #ai-webcam {
      width: 100%;
      height: 100%;
      object-fit: cover;
      display: none;
    }
    .prediction-grid {
      display: grid;
      grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
      gap: 10px;
    }
    .prediction-card {
      background: white;
      border: 2px solid #C5CAE9;
      border-radius: 16px;
      padding: 12px;
      text-align: center;
      font-weight: 800;
    }
    .prediction-card strong {
      color: #3949AB;
      display: block;
      font-size: 1.05rem;
      margin-top: 4px;
    }
    .ai-plant-card {
      min-height: 0;
      padding: 16px 20px;
    }
    .ai-plant-card .dialogue-text {
      min-height: 58px;
      margin-bottom: 10px;
      white-space: pre-line;
    }
    .ai-plant-card svg {
      width: 200px !important;
      height: 225px !important;
    }

    /* First-page photosynthesis classroom. All motion is scoped to the visible lesson scene. */
    .lesson-page { max-width: 1120px; margin: 0 auto 42px; background-color: var(--env-theme-bg); }
    .lesson-hero { background: #DDF3D9; border: 4px solid #72B978; border-radius: 28px; padding: 28px 30px; display: grid; grid-template-columns: 1fr auto; gap: 24px; align-items: center; box-shadow: 0 8px 0 rgba(63, 122, 69, .12); }
    .lesson-kicker { color: #237C38; font-weight: 800; font-size: 1rem; margin-bottom: 7px; }
    .lesson-hero h1 { color: #216E32; font-size: clamp(2rem, 4vw, 3.4rem); line-height: 1.2; }
    .lesson-hero p { margin-top: 10px; font-size: 1.08rem; line-height: 1.7; max-width: 650px; }
    .keep-together { white-space: nowrap; }
    .lesson-hero-sprout { width: 175px; height: 130px; }
    .lesson-progress-nav { position: sticky; top: 8px; z-index: 8; background: rgba(255,255,255,.95); border: 2px solid #B9DFB9; border-radius: 14px; padding: 10px 14px; margin: 18px 0; box-shadow: 0 4px 12px rgba(37,96,54,.08); }
    .lesson-progress-text { display: flex; justify-content: space-between; gap: 12px; color: #27683A; font-weight: 800; font-size: .95rem; }
    .lesson-progress-track { height: 9px; margin-top: 8px; overflow: hidden; border-radius: 999px; background: #E4F0E3; }
    .lesson-progress-fill { height: 100%; width: 0; background: #54A95B; border-radius: inherit; transition: width .35s ease; }
    .lesson-section { display: grid; grid-template-columns: minmax(0, 1.05fr) minmax(300px, .95fr); gap: 24px; align-items: center; margin: 26px 0; padding: 28px; background: #FFF; border: 3px solid #D7E9D0; border-radius: 24px; box-shadow: 0 7px 0 rgba(57,103,61,.07); scroll-margin-top: 92px; }
    .lesson-section:nth-of-type(even) { background: #FFFDF5; border-color: #F0D99C; }
    .lesson-copy h2 { color: #226A35; font-size: clamp(1.6rem, 3vw, 2.3rem); line-height: 1.25; margin-bottom: 10px; }
    .lesson-copy p { font-size: 1.07rem; line-height: 1.75; }
    .lesson-chip { display: inline-block; background: #FFF3BB; color: #6A5613; border: 2px solid #E4BE49; border-radius: 999px; padding: 4px 12px; font-weight: 800; font-size: .9rem; margin-bottom: 9px; }
    .lesson-keypoint { margin-top: 15px; background: #F0F8EF; border-left: 6px solid #53A858; padding: 12px 15px; border-radius: 0 12px 12px 0; font-weight: 700; line-height: 1.55; }
    .lesson-controls { display: flex; flex-wrap: wrap; gap: 9px; margin-top: 17px; }
    .lesson-action { border: 0; border-radius: 10px; padding: 10px 14px; background: #347C45; color: #fff; cursor: pointer; font-size: .97rem; font-weight: 800; }
    .lesson-action.secondary { color: #347C45; background: #E6F3E6; border: 2px solid #A8D6AA; }
    .lesson-action:hover { filter: brightness(1.06); transform: translateY(-1px); }
    .lesson-scene { position: relative; min-height: 320px; overflow: hidden; border-radius: 20px; background: #EAF6E6; border: 3px dashed #A9D5A8; display: grid; place-items: center; }
    .lesson-scene.sky { background: #DDF1FB; border-color: #9ACFDF; }
    .lesson-scene.warm { background: #FFF0CF; border-color: #EDC976; }
    .lesson-scene svg { width: 100%; height: 320px; max-width: 510px; }
    .scene-caption { position: absolute; left: 14px; right: 14px; bottom: 12px; text-align: center; color: #315C38; font-weight: 800; font-size: .92rem; }
    .lesson-quiz { grid-column: 1 / -1; background: #F7FBF5; border: 2px solid #B5DDB5; border-radius: 16px; padding: 18px; }
    .lesson-quiz h3 { color: #286B38; font-size: 1.15rem; margin-bottom: 11px; }
    .quiz-options { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 9px; }
    .quiz-choice { background: #fff; color: #2C3E50; border: 2px solid #C5E0C3; border-radius: 10px; cursor: pointer; padding: 10px; font: inherit; font-weight: 700; text-align: left; }
    .quiz-choice:hover { background: #EAF7E8; }
    .quiz-choice.correct { background: #DCF3D8; border-color: #4EAB59; color: #1E6D31; }
    .quiz-choice.incorrect { background: #FFF0F0; border-color: #E79B9B; color: #A43D3D; }
    .quiz-feedback { min-height: 24px; margin-top: 10px; font-weight: 800; line-height: 1.5; }
    .quiz-feedback.correct { color: #267938; }
    .quiz-feedback.incorrect { color: #B04343; }
    .lesson-final { background: #E3F2DF; border-color: #75B779; }
    .sensor-challenge { background: #FFF; border: 3px solid #82BE82; border-radius: 16px; padding: 16px; margin-top: 16px; }
    .sensor-reading { display: grid; grid-template-columns: repeat(2, 1fr); gap: 10px; margin: 12px 0; }
    .sensor-reading div { text-align: center; background: #EAF6E7; border-radius: 12px; padding: 12px; color: #236C35; font-weight: 800; }
    .sensor-reading strong { display: block; font-size: 1.55rem; }
    .lesson-badge { display: none; text-align: center; margin-top: 18px; background: #FFF7D7; border: 3px solid #E7BE43; border-radius: 18px; padding: 16px; color: #765904; font-size: 1.15rem; font-weight: 900; }
    .lesson-badge.visible { display: block; animation: badgePop .45s ease both; }
    .lesson-plant { transform-origin: center bottom; animation: none; }
    .active-scene .lesson-plant { animation: plantSway 2.2s ease-in-out infinite; }
    .sun-rays { transform-origin: center; animation: none; }
    .active-scene .sun-rays { animation: sunPulse 1.7s ease-in-out infinite; }
    .water-drop { animation: none; }
    .active-scene .water-drop { animation: waterRise 2.4s ease-in-out infinite; }
    .active-scene .water-drop.second { animation-delay: 1.2s; }
    .gas-co2 { animation: none; }
    .active-scene .gas-co2 { animation: gasInLeft 3s ease-in-out infinite; }
    .gas-o2 { animation: none; }
    .active-scene .gas-o2 { animation: gasOutRight 3s ease-in-out infinite; }
    .food-dot { animation: none; }
    .active-scene .food-dot { animation: foodFlow 2.8s ease-in-out infinite; }
    .factory-arrow { animation: none; }
    .active-scene .factory-arrow { animation: arrowGlow 1.2s ease-in-out infinite alternate; }
    .factory-material { animation: none; }
    .active-scene .factory-material { animation: factoryMaterial 2.8s ease-in-out infinite; }
    .intro-caption { top: 12px; bottom: auto; }
    .process-caption { top: 12px; bottom: auto; }
    .final-caption { top: 12px; bottom: auto; }
    .factory-caption { display: none; }
    .product-output { animation: none; }
    .active-scene .product-output { animation: productOut 3s ease-in-out infinite; }
    @keyframes plantSway { 50% { transform: rotate(2deg) translateY(-4px); } }
    @keyframes sunPulse { 50% { transform: scale(1.09); opacity: .72; } }
    @keyframes waterRise { 0% { transform: translateY(55px); opacity: 0; } 20% { opacity: 1; } 80% { opacity: 1; } 100% { transform: translateY(-115px); opacity: 0; } }
    @keyframes gasInLeft { 0% { transform: translateX(-95px); opacity: 0; } 18% { opacity: 1; } 100% { transform: translateX(110px); opacity: 0; } }
    @keyframes gasOutRight { 0% { transform: translateX(-30px); opacity: 0; } 18% { opacity: 1; } 100% { transform: translateX(125px); opacity: 0; } }
    @keyframes foodFlow { 0% { transform: translateY(-62px); opacity: 0; } 20% { opacity: 1; } 100% { transform: translateY(120px); opacity: 0; } }
    @keyframes arrowGlow { to { opacity: .4; transform: translateX(5px); } }
    @keyframes factoryMaterial { 0% { transform: translateX(-46px); opacity: 0; } 18% { opacity: 1; } 72% { opacity: 1; } 100% { transform: translateX(64px); opacity: 0; } }
    @keyframes productOut { 0% { transform: translateX(-12px); opacity: 0; } 18% { opacity: 1; } 100% { transform: translateX(118px); opacity: 0; } }
    @keyframes badgePop { from { transform: scale(.85); opacity: 0; } to { transform: scale(1); opacity: 1; } }
    @media (max-width: 760px) { body { overflow-x: hidden; } header { flex-wrap: wrap; gap: 8px; padding: 10px 8px; } .nav-btn { flex: 1 1 100%; min-width: 0; padding: 8px 7px; font-size: .9rem; } .container, .lesson-page { width: 100%; min-width: 0; } .lesson-hero, .lesson-section { width: 100%; grid-template-columns: minmax(0, 1fr); padding: 20px; min-width: 0; } .lesson-copy { min-width: 0; } .lesson-hero h1, .lesson-copy h2, .lesson-copy p { overflow-wrap: anywhere; word-break: break-all; } .lesson-hero-sprout { display: none; } .quiz-options { grid-template-columns: 1fr; } .lesson-scene { min-height: 285px; } .lesson-scene svg { height: 285px; } }
    @media (max-width: 760px) {
      .lesson-hero h1 span { display: block; }
      .lesson-hero p, .lesson-copy p { max-width: 320px; }
    }