/* ==========================================================================
   DOPI NOTE - 主樣式表 (重構版)
   邏輯清晰、易於維護的組織結構
   ========================================================================== */

/* ==========================================================================
   1. CSS 變數與基礎設定
   ========================================================================== */
:root {
  /* 品牌色彩系統 */
  --brand: #0a74ff;
  --brand-hover: #0969e3;
  --brand-light: rgba(10, 116, 255, 0.1);

  /* 基礎色彩系統 */
  --bg: #fafafa;
  --surface: #ffffff;
  --elevated: #ffffff;
  --section: #f8f9fa;
  --border: #e5e7eb;
  --text: #1f2937;
  --text-light: #4b5563;
  --muted: #6b7280;

  /* 尺寸系統 */
  --container-width: 1200px;
  --navbar-height: 64px;
  --radius: 12px;
  --radius-sm: 8px;
  --radius-full: 9999px;

  /* 間距系統 */
  --spacing-xs: 0.5rem;   /* 8px */
  --spacing-sm: 0.75rem;  /* 12px */
  --spacing-md: 1rem;     /* 16px */
  --spacing-lg: 1.5rem;   /* 24px */
  --spacing-xl: 2rem;     /* 32px */
  --spacing-2xl: 3rem;    /* 48px */
  --spacing-3xl: 4rem;    /* 64px */
  --spacing-4xl: 6rem;    /* 96px */

  /* 字體大小系統 */
  --text-xs: clamp(0.75rem, 0.7rem + 0.25vw, 0.8rem);
  --text-sm: clamp(0.875rem, 0.8rem + 0.3vw, 0.9rem);
  --text-base: clamp(0.9rem, 0.86rem + 0.35vw, 0.95rem);
  --text-lg: clamp(1rem, 0.9rem + 0.5vw, 1.125rem);
  --text-xl: clamp(1.2rem, 1.12rem + 0.6vw, 1.25rem);
  --text-2xl: clamp(1.5rem, 1.35rem + 0.75vw, 1.625rem);
  --text-3xl: clamp(1.875rem, 1.65rem + 1.125vw, 2.25rem);
  --text-4xl: clamp(2.25rem, 1.95rem + 1.5vw, 3rem);
  --text-5xl: clamp(3rem, 2.5rem + 2.5vw, 4.5rem);

  /* 陰影系統 */
  --shadow: 0 2px 8px rgba(0,0,0,0.08);
  --shadow-lg: 0 8px 25px rgba(0,0,0,0.12);

  /* 動畫系統 */
  --transition: 300ms cubic-bezier(0.4, 0, 0.2, 1);
}

/* ==========================================================================
   2. 基礎重置與通用樣式
   ========================================================================== */
*, *::before, *::after {
  box-sizing: border-box;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, 'Noto Sans TC', sans-serif;
  line-height: 1.6;
  color: var(--text);
  background: var(--bg);
  margin: 0;
  padding-top: var(--navbar-height);
}

h1, h2, h3, h4, h5, h6 {
  font-weight: 400;
  line-height: 1.2;
  color: var(--text);
  margin: 0;
}

p { margin: 0; }

a {
  color: var(--brand);
  text-decoration: none;
  transition: color var(--transition);
}

a:hover { color: var(--brand-hover); }

/* 中文文字斷字優化 */
.feature-main-title,
.use-content h3,
.problem-title,
.slogan-text,
.slogan-subtitle {
  word-break: keep-all;
  overflow-wrap: break-word;
  line-break: strict;
}

/* ==========================================================================
   3. 佈局系統
   ========================================================================== */
.container {
  max-width: var(--container-width);
  margin: 0 auto;
  padding: 0 var(--spacing-lg);
}

.section {
  padding: var(--spacing-4xl) 0;
}

.section-title {
  font-size: var(--text-4xl);
  font-weight: 400;
  text-align: center;
  margin-bottom: var(--spacing-2xl);
  color: var(--text);
}

.section-subtitle {
  font-size: var(--text-xl);
  color: var(--text-light);
  font-weight: 400;
  text-align: center;
  margin-top: calc(var(--spacing-2xl) * -1 + var(--spacing-md));
  margin-bottom: var(--spacing-2xl);
}

/* ==========================================================================
   4. 組件庫
   ========================================================================== */

/* 按鈕組件 */
.btn, .nav-cta {
  display: inline-flex;
  align-items: center;
  gap: 0.5em;
  background: var(--brand);
  color: #fff;
  padding: var(--spacing-xs) 1.2rem;
  border-radius: var(--radius-full);
  font-size: var(--text-base);
  font-weight: 400;
  border: 1px solid transparent;
  transition: transform var(--transition), background var(--transition), box-shadow var(--transition);
  will-change: transform;
  text-decoration: none;
}

.btn:hover, .nav-cta:hover {
  background: var(--brand-hover);
  transform: translateY(-1px);
}

.btn:active, .nav-cta:active {
  transform: translateY(0);
}

/* 卡片組件 */
.card,
.feature-card,
.use-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  transition: transform var(--transition), box-shadow var(--transition);
}

.card:hover,
.feature-card:hover,
.use-card:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-lg);
}

/* ==========================================================================
   5. 導航列
   ========================================================================== */
.navbar {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  background: rgba(255, 255, 255, 0.9);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--border);
  z-index: 1000;
  height: var(--navbar-height);
}

.nav-container {
  height: 100%;
  display: flex;
  justify-content: space-between;
  align-items: center;
  max-width: var(--container-width);
  margin: 0 auto;
  padding: 0 var(--spacing-lg);
}

.nav-brand {
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
  font-family: 'Inter', 'Poppins', -apple-system, BlinkMacSystemFont, sans-serif;
  font-weight: 700;
  font-size: 26px;
  letter-spacing: -0.02em;
  color: var(--text);
}

.nav-logo {
  inline-size: 44px;
  block-size: 44px;
  border-radius: var(--radius-sm);
}

.nav-actions {
  display: flex;
  align-items: center;
  gap: var(--spacing-md);
}

/* ==========================================================================
   6. Hero 區塊
   ========================================================================== */
.video-hero {
  min-height: calc(85vh - var(--navbar-height));
  padding-top: var(--spacing-2xl);
  text-align: center;
}

.video-hero .container {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--spacing-md);
  margin-bottom: var(--spacing-lg);
}

.video-hero .hero-title {
  font-size: var(--text-4xl);
  font-weight: 400;
  color: var(--text);
  margin-bottom: var(--spacing-xs);
  line-height: 1.15;
  letter-spacing: -0.02em;
}


.video-hero .hero-subtitle {
  font-size: var(--text-xl);
  color: var(--text-light);
  font-weight: 400;
  margin-bottom: var(--spacing-md);
}

/* ==========================================================================
   7. 影片容器
   ========================================================================== */
.video-container {
  position: relative;
  inline-size: 100%;
  max-width: 900px;
  margin: 0 auto;
  padding: 0 var(--spacing-lg);
  padding-bottom: 56.25%;
  block-size: 0;
  overflow: hidden;
  border-radius: var(--radius);
  box-shadow: var(--shadow-lg);
  transform: translateZ(0);
  backface-visibility: hidden;
  isolation: isolate;
  cursor: pointer;
  border: 1px solid var(--border);
  box-sizing: border-box;
}

.video-container iframe {
  position: absolute;
  inset: 0;
  inline-size: 100%;
  block-size: 100%;
  border-radius: var(--radius);
  background: var(--elevated);
  border: none;
}

/* ==========================================================================
   8. 問題解決方案區塊
   ========================================================================== */
.problem-solution {
  text-align: center;
  padding-block: var(--spacing-4xl);
  background: var(--section);
}

.problem-solution-card {
  max-width: 900px;
  margin-inline: auto;
  padding: var(--spacing-3xl) var(--spacing-lg);
}

.problem-title {
  font-size: var(--text-4xl);
  font-weight: 400;
  margin-bottom: var(--spacing-lg);
  color: var(--text);
  line-height: 1.2;
}

.problem-subtitle {
  font-size: var(--text-xl);
  color: var(--text-light);
  margin-bottom: var(--spacing-2xl);
  font-weight: 400;
}

/* ==========================================================================
   9. 使用場景區塊
   ========================================================================== */
.use-cases {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-xl);
  max-width: 1000px;
  margin: 0 auto;
}

.use-card.horizontal {
  display: flex;
  align-items: center;
  gap: var(--spacing-2xl);
  min-height: 320px;
  overflow: hidden;
}

.use-card.horizontal.reverse {
  flex-direction: row-reverse;
}

.use-card.horizontal img,
.use-card.horizontal iframe {
  inline-size: clamp(320px, 42vw, 520px);
  block-size: clamp(220px, 30vw, 350px);
  object-fit: cover;
  flex-shrink: 0;
  border: none;
  border-radius: var(--radius);
}

.use-card.horizontal .use-content {
  padding: clamp(28px, 4vw, 60px);
  flex: 1;
}

.use-content h3 {
  font-size: var(--text-2xl);
  font-weight: 400;
  margin-bottom: var(--spacing-sm);
}

.use-description {
  font-size: var(--text-lg);
  font-weight: 400;
  color: var(--text-light);
  line-height: 1.6;
  margin: 0;
}

/* ==========================================================================
   10. 功能特色區塊
   ========================================================================== */
.features {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--spacing-xl);
  max-width: var(--container-width);
  margin: 0 auto;
}

.feature-card {
  padding: var(--spacing-2xl) var(--spacing-lg);
  text-align: center;
  min-height: 280px;
  display: flex;
  flex-direction: column;
  justify-content: flex-start;
}

.feature-main-title {
  font-size: var(--text-2xl);
  font-weight: 400;
  margin-bottom: var(--spacing-sm);
  color: var(--text);
}

.feature-list {
  list-style: none;
  padding: 0;
  margin: 0;
  text-align: left;
}

.feature-list li {
  color: var(--text);
  font-size: var(--text-lg);
  line-height: 1.8;
  padding-left: 1.5em;
  position: relative;
  margin-bottom: var(--spacing-xs);
}

.feature-list li:last-child {
  margin-bottom: 0;
}

.feature-list li::before {
  content: "✓";
  position: absolute;
  left: 0;
  color: var(--brand);
  font-weight: 700;
}

/* 特色卡片莫蘭迪色系配色 */
.feature-card-1 {
  background: rgba(145, 168, 208, 0.35);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  border-color: rgba(145, 168, 208, 0.2);
}

.feature-card-2 {
  background: rgba(176, 196, 177, 0.35);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  border-color: rgba(176, 196, 177, 0.2);
}

.feature-card-3 {
  background: rgba(216, 191, 185, 0.35);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  border-color: rgba(216, 191, 185, 0.2);
}

/* ==========================================================================
   11. 品牌標語區塊
   ========================================================================== */
.brand-slogan {
  padding: var(--spacing-4xl) 0;
  text-align: center;
  position: relative;
  overflow: hidden;
}

.slogan-subtitle {
  font-size: var(--text-2xl);
  color: var(--text);
  font-weight: 400;
  margin-top: var(--spacing-md);
  text-align: center;
}

/* ==========================================================================
   12. 下載區塊
   ========================================================================== */
.download-apps {
  text-align: center;
  padding-block: 40px;
}

.download-title {
  font-size: var(--text-3xl);
  color: var(--text-light);
}

.app-badges {
  display: flex;
  gap: var(--spacing-lg);
  justify-content: center;
  align-items: center;
  flex-wrap: wrap;
  margin-top: var(--spacing-xl);
}

.app-badge {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  transition: transform var(--transition), opacity var(--transition);
}

.app-badge:hover {
  transform: translateY(-2px);
  opacity: 0.9;
}

.app-badge.app-store img {
  height: 54px;
  width: auto;
}

.app-badge.google-play img {
  height: 73px;
  width: auto;
}

/* ==========================================================================
   13. 聯絡區塊
   ========================================================================== */
.contact-bar {
  background: var(--section);
  padding-block: var(--spacing-lg);
  border-bottom: 1px solid var(--border);
}

.contact-info {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: var(--spacing-lg);
  font-size: var(--text-base);
  flex-wrap: wrap;
}

.contact-email {
  display: flex;
  align-items: center;
  gap: var(--spacing-xs);
}

.contact-info span {
  color: var(--text-light);
}

.email-link {
  display: inline-flex;
  align-items: center;
  color: var(--brand);
  text-decoration: none;
  transition: transform var(--transition), opacity var(--transition);
}

.email-link:hover {
  transform: translateY(-2px);
  opacity: 0.8;
}

.email-icon {
  flex-shrink: 0;
  color: var(--brand);
  width: 24px;
  height: 24px;
}

.contact-info a {
  color: var(--brand);
  text-decoration: none;
  font-weight: 400;
}

.contact-info a:hover {
  text-decoration: underline;
}

/* ==========================================================================
   14. Footer
   ========================================================================== */
footer {
  border-top: 1px solid var(--border);
  padding-block: var(--spacing-2xl);
  text-align: center;
}

footer p {
  color: var(--muted);
  font-size: var(--text-base);
}

/* ==========================================================================
   15. 響應式設計
   ========================================================================== */

/* 大螢幕優化 (1200px以下) */
@media (max-width: 1200px) {
  .video-container {
    max-width: 90%;
  }
}

/* 平板橫向 (980px以下) */
@media (max-width: 980px) {
  .video-hero {
    min-height: calc(75vh - var(--navbar-height));
  }

  .video-hero .container {
    gap: var(--spacing-lg);
  }

  .video-hero .hero-title {
    font-size: var(--text-4xl);
  }

  .video-hero .hero-subtitle {
    font-size: var(--text-xl);
  }

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

/* 平板直向 (768px以下) */
@media (max-width: 768px) {
  .video-hero {
    min-height: calc(70vh - var(--navbar-height));
  }

  .video-hero .container {
    gap: var(--spacing-lg);
  }

  /* 主標題層級統一 (H1, H2) */
  .video-hero .hero-title,
  .section-title,
  .problem-title {
    font-size: var(--text-3xl);
  }

  /* 副標題層級統一 */
  .video-hero .hero-subtitle,
  .problem-subtitle {
    font-size: var(--text-lg);
  }

  /* 次標題層級統一 (H3) */
  .feature-main-title,
  .use-content h3 {
    font-size: var(--text-xl);
  }

  .video-container {
    max-width: 95%;
  }

  .use-card.horizontal {
    min-height: 300px;
  }

  .use-card.horizontal img {
    inline-size: clamp(280px, 50vw, 420px);
    block-size: 280px;
  }

  .use-card.horizontal .use-content {
    padding: 45px;
  }

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

  .brand-slogan {
    padding: var(--spacing-3xl) 0;
  }

  .slogan-text {
    font-size: var(--text-3xl);
    line-height: 1.3;
  }
}

/* 手機橫向 (640px以下) */
@media (max-width: 640px) {
  /* 導航列優化 */
  .nav-container {
    padding: 0 var(--spacing-md);
  }

  .nav-logo {
    inline-size: 36px;
    block-size: 36px;
  }

  .nav-brand {
    font-size: 20px;
  }

  .nav-cta {
    font-size: var(--text-xs);
    padding: 6px 12px;
  }

  .container {
    padding-inline: var(--spacing-md);
  }

  .video-hero {
    min-height: calc(65vh - var(--navbar-height));
  }

  .video-hero .container {
    gap: var(--spacing-md);
  }

  /* 主標題層級統一 (H1, H2) */
  .video-hero .hero-title,
  .section-title,
  .problem-title {
    font-size: var(--text-2xl);
    font-weight: 600;
  }

  .video-hero .hero-title {
    margin-bottom: var(--spacing-xs);
  }

  /* 副標題層級統一 */
  .video-hero .hero-subtitle,
  .problem-subtitle,
  .section-subtitle,
  .slogan-subtitle {
    font-size: var(--text-xl);
    font-weight: 400;
  }

  .video-hero .hero-subtitle {
    margin-bottom: var(--spacing-lg);
  }

  /* 次標題層級統一 (H3) */
  .feature-main-title,
  .use-content h3 {
    font-size: var(--text-lg);
    font-weight: 600;
  }

  .video-container {
    max-width: 90%;
  }

  .use-card.horizontal,
  .use-card.horizontal.reverse {
    flex-direction: column;
    min-height: auto;
  }

  .use-card.horizontal img,
  .use-card.horizontal iframe {
    inline-size: 100%;
    block-size: 240px;
  }

  .use-card.horizontal .use-content {
    padding: 28px;
    text-align: center;
  }

  .app-badges {
    flex-direction: column;
    gap: var(--spacing-md);
  }

  .app-badge.app-store img {
    height: 48px;
  }

  .app-badge.google-play img {
    height: 66px;
  }

  .section {
    padding-block: 60px;
  }

  .section-title {
    margin-bottom: var(--spacing-2xl);
  }

  .problem-solution-card {
    padding: var(--spacing-2xl) var(--spacing-lg);
    margin-inline: var(--spacing-sm);
  }

  .features {
    grid-template-columns: 1fr;
    gap: var(--spacing-lg);
  }

  .feature-card {
    padding: var(--spacing-xl) var(--spacing-md);
  }

  .feature-main-title {
    line-height: 1.4;
  }

  .use-description {
    line-height: 1.7;
    font-size: var(--text-lg);
  }
}

/* 手機直向 (480px以下) */
@media (max-width: 480px) {
  /* 主標題層級適度調整 (H1, H2) */
  .video-hero .hero-title,
  .section-title,
  .problem-title {
    font-size: var(--text-2xl);
  }

  /* 副標題層級改善可讀性 */
  .video-hero .hero-subtitle,
  .problem-subtitle {
    font-size: var(--text-base);
  }

  /* 次標題層級改善可讀性 (H3) */
  .feature-main-title,
  .use-content h3 {
    font-size: var(--text-lg);
  }

  .slogan-text {
    font-size: var(--text-2xl);
    background: var(--brand);
    background-clip: text;
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    animation: none;
  }
}

/* ==========================================================================
   15. 語言切換器
   ========================================================================== */
.language-switcher {
  position: relative;
}

.current-language {
  background: none;
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 4px 10px;
  font-size: 0.8125rem;
  color: var(--text);
  cursor: pointer;
  display: flex;
  align-items: center;
  gap: var(--spacing-xs);
  transition: all 0.2s ease;
  min-width: 60px;
  justify-content: center;
}

.current-language:hover {
  border-color: var(--brand);
  background: var(--brand-light);
}

.current-language::after {
  content: '▼';
  font-size: 10px;
  color: var(--muted);
  transition: transform 0.2s ease;
}

.language-dropdown {
  position: absolute;
  top: calc(100% + 4px);
  right: 0;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  box-shadow: var(--shadow-lg);
  min-width: 90px;
  z-index: 1001;
  opacity: 0;
  visibility: hidden;
  transform: translateY(-10px);
  transition: all 0.2s ease;
}

.language-dropdown.show {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
}

.language-option {
  width: 100%;
  background: none;
  border: none;
  padding: 6px 10px;
  font-size: 0.8125rem;
  color: var(--text);
  cursor: pointer;
  text-align: left;
  transition: background-color 0.2s ease;
}

.language-option:hover {
  background: var(--brand-light);
  color: var(--brand);
}

.language-option:first-child {
  border-radius: var(--radius-sm) var(--radius-sm) 0 0;
}

.language-option:last-child {
  border-radius: 0 0 var(--radius-sm) var(--radius-sm);
}

/* 響應式調整 */
@media (max-width: 640px) {
  .contact-info {
    flex-direction: column;
    gap: var(--spacing-md);
  }

  .current-language {
    padding: var(--spacing-xs);
    min-width: 60px;
    font-size: var(--text-xs);
  }

  .language-dropdown {
    min-width: 100px;
  }

  .language-option {
    padding: var(--spacing-xs) var(--spacing-sm);
    font-size: var(--text-xs);
  }
}

/* ==========================================================================
   16. 動畫優化
   ========================================================================== */
@media (prefers-reduced-motion: reduce) {
  .video-hero .hero-title::after {
    animation: none;
  }

  * {
    animation: none !important;
    transition: none !important;
  }

  .feature-card:hover,
  .use-card:hover,
  .btn:hover,
  .nav-cta:hover {
    transform: none !important;
  }
}