/* ============================================
   健身动作图谱 — Apple 设计系统
   基于 apple-DESIGN.md 规范
   ============================================ */

:root {
  /* 品牌与强调色 */
  --color-primary: #0066cc;
  --color-primary-focus: #0071e3;
  --color-primary-on-dark: #2997ff;

  /* 表面色 */
  --color-canvas: #ffffff;
  --color-parchment: #f5f5f7;
  --color-pearl: #fafafc;
  --color-tile-1: #272729;
  --color-tile-2: #2a2a2c;
  --color-tile-3: #252527;
  --color-black: #000000;
  --color-chip-translucent: rgba(210, 210, 215, 0.64);

  /* 文本色 */
  --color-ink: #1d1d1f;
  --color-body: #1d1d1f;
  --color-body-on-dark: #ffffff;
  --color-body-muted: #cccccc;
  --color-ink-muted-80: #333333;
  --color-ink-muted-48: #7a7a7a;

  /* 发际线与边框 */
  --color-divider-soft: #f0f0f0;
  --color-hairline: #e0e0e0;

  /* 圆角 */
  --rounded-sm: 8px;
  --rounded-md: 11px;
  --rounded-lg: 18px;
  --rounded-pill: 9999px;

  /* 阴影：仅产品图像 */
  --shadow-product: 3px 5px 30px 0 rgba(0, 0, 0, 0.22);

  /* 字体 */
  --font-display: "SF Pro Display", system-ui, -apple-system, BlinkMacSystemFont, sans-serif;
  --font-text: "SF Pro Text", system-ui, -apple-system, BlinkMacSystemFont, sans-serif;

  /* 间距 */
  --spacing-xxs: 4px;
  --spacing-xs: 8px;
  --spacing-sm: 12px;
  --spacing-md: 17px;
  --spacing-lg: 24px;
  --spacing-xl: 32px;
  --spacing-xxl: 48px;
  --spacing-section: 80px;
}

/* ====== Reset ====== */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; -webkit-text-size-adjust: 100%; }
body {
  font-family: var(--font-text);
  font-size: 17px;
  font-weight: 400;
  line-height: 1.47;
  letter-spacing: -0.374px;
  color: var(--color-body);
  background: var(--color-canvas);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}
.hidden { display: none !important; }
a { color: var(--color-primary); text-decoration: none; }
img, video { max-width: 100%; display: block; }

/* ====== 排版 ====== */
.hero {
  font-family: var(--font-display);
  font-size: 56px;
  font-weight: 600;
  line-height: 1.07;
  letter-spacing: -0.28px;
  color: var(--color-ink);
}
.display-lg {
  font-family: var(--font-display);
  font-size: 40px;
  font-weight: 600;
  line-height: 1.1;
  letter-spacing: 0;
  color: var(--color-ink);
}
.display-md {
  font-family: var(--font-display);
  font-size: 34px;
  font-weight: 600;
  line-height: 1.47;
  letter-spacing: -0.374px;
}
.lead {
  font-size: 28px;
  font-weight: 400;
  line-height: 1.14;
  letter-spacing: 0.196px;
  color: var(--color-ink);
}
.tagline {
  font-size: 21px;
  font-weight: 600;
  line-height: 1.19;
  letter-spacing: 0.231px;
  color: var(--color-ink);
}
.body-text {
  font-size: 17px;
  font-weight: 400;
  line-height: 1.47;
  letter-spacing: -0.374px;
  color: var(--color-body);
}
.body-strong {
  font-size: 17px;
  font-weight: 600;
  line-height: 1.24;
  letter-spacing: -0.374px;
}
.caption {
  font-size: 14px;
  font-weight: 400;
  line-height: 1.43;
  letter-spacing: -0.224px;
}
.fine-print {
  font-size: 12px;
  font-weight: 400;
  line-height: 1.0;
  letter-spacing: -0.12px;
  color: var(--color-ink-muted-48);
}
.body-muted { color: var(--color-ink-muted-48); }

/* ====== 全局导航 ====== */
.global-nav {
  background: var(--color-black);
  height: 44px;
  position: sticky;
  top: 0;
  z-index: 1000;
  display: flex;
  align-items: center;
}
.global-nav-inner {
  max-width: 1024px;
  width: 100%;
  margin: 0 auto;
  padding: 0 22px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}
.nav-logo {
  font-family: var(--font-text);
  font-size: 12px;
  font-weight: 400;
  letter-spacing: -0.12px;
  color: var(--color-body-on-dark);
}
.nav-links {
  display: flex;
  gap: 20px;
}
.nav-links a {
  font-size: 12px;
  font-weight: 400;
  letter-spacing: -0.12px;
  color: var(--color-body-on-dark);
  opacity: 0.88;
}
.nav-links a:hover { opacity: 1; }

/* ====== 主视觉区块 ====== */
.hero-section {
  background: var(--color-canvas);
  padding: var(--spacing-section) 22px;
  text-align: center;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 16px;
}
.hero-section .lead { color: var(--color-ink-muted-80); max-width: 600px; }
.hero-actions {
  display: flex;
  gap: 12px;
  margin-top: 12px;
  flex-wrap: wrap;
  justify-content: center;
}

/* ====== 按钮 ====== */
.button-primary {
  background: var(--color-primary);
  color: #ffffff;
  font-family: var(--font-text);
  font-size: 17px;
  font-weight: 400;
  line-height: 1.47;
  border-radius: var(--rounded-pill);
  padding: 11px 22px;
  border: none;
  cursor: pointer;
  display: inline-block;
  transition: transform 0.15s ease;
  text-align: center;
}
.button-primary:active { transform: scale(0.95); }
.button-primary:focus-visible { outline: 2px solid var(--color-primary-focus); outline-offset: 2px; }

.button-secondary-pill {
  background: transparent;
  color: var(--color-primary);
  font-family: var(--font-text);
  font-size: 17px;
  font-weight: 400;
  border-radius: var(--rounded-pill);
  padding: 11px 22px;
  border: 1px solid var(--color-primary);
  cursor: pointer;
  display: inline-block;
  transition: transform 0.15s ease;
  text-align: center;
}
.button-secondary-pill:active { transform: scale(0.95); }

/* ====== 子导航：毛玻璃 ====== */
.sub-nav-frosted {
  position: sticky;
  top: 44px;
  z-index: 900;
  background: rgba(245, 245, 247, 0.8);
  backdrop-filter: saturate(180%) blur(20px);
  -webkit-backdrop-filter: saturate(180%) blur(20px);
  border-bottom: 1px solid rgba(0, 0, 0, 0.08);
}
.sub-nav-inner {
  max-width: 1440px;
  margin: 0 auto;
  padding: 12px 22px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  flex-wrap: wrap;
}
.filter-group {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
  flex: 1;
}
.chip {
  background: transparent;
  border: 1px solid var(--color-hairline);
  border-radius: var(--rounded-pill);
  padding: 8px 16px;
  font-family: var(--font-text);
  font-size: 14px;
  font-weight: 400;
  letter-spacing: -0.224px;
  color: var(--color-ink);
  cursor: pointer;
  transition: all 0.15s ease;
  white-space: nowrap;
}
.chip:hover { background: var(--color-pearl); }
.chip:active { transform: scale(0.95); }
.chip-active {
  background: var(--color-ink);
  color: var(--color-body-on-dark);
  border-color: var(--color-ink);
}
.filter-right {
  display: flex;
  gap: 8px;
  align-items: center;
}
.equipment-select {
  background: var(--color-canvas);
  border: 1px solid var(--color-hairline);
  border-radius: var(--rounded-pill);
  padding: 8px 16px;
  font-family: var(--font-text);
  font-size: 14px;
  color: var(--color-ink);
  cursor: pointer;
  appearance: none;
  -webkit-appearance: none;
}
.search-input {
  background: var(--color-canvas);
  border: 1px solid rgba(0, 0, 0, 0.08);
  border-radius: var(--rounded-pill);
  padding: 8px 20px;
  font-family: var(--font-text);
  font-size: 14px;
  color: var(--color-ink);
  height: 44px;
  min-width: 200px;
  outline: none;
}
.search-input:focus {
  border-color: var(--color-primary);
  box-shadow: 0 0 0 2px var(--color-primary-focus);
}

/* ====== 结果计数栏 ====== */
.result-bar {
  max-width: 1440px;
  margin: 0 auto;
  padding: 24px 22px 8px;
}
.result-count {
  font-size: 14px;
  font-weight: 400;
  color: var(--color-ink-muted-48);
  letter-spacing: -0.224px;
}

/* ====== 卡片网格 ====== */
.grid-container {
  max-width: 1440px;
  margin: 0 auto;
  padding: 0 22px;
  display: grid;
  grid-template-columns: repeat(5, 1fr);
  gap: 20px;
}

/* ====== 工具卡片 ====== */
.store-utility-card {
  background: var(--color-canvas);
  border: 1px solid var(--color-hairline);
  border-radius: var(--rounded-lg);
  overflow: hidden;
  cursor: pointer;
  transition: transform 0.15s ease;
  display: flex;
  flex-direction: column;
}
.store-utility-card:active { transform: scale(0.97); }
.card-media-wrap {
  background: var(--color-parchment);
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 20px;
  aspect-ratio: 1;
}
.card-media {
  width: 100%;
  height: 100%;
  object-fit: contain;
  border-radius: var(--rounded-sm);
  filter: drop-shadow(var(--shadow-product));
}
.card-body {
  padding: var(--spacing-lg);
  display: flex;
  flex-direction: column;
  gap: 4px;
}
.card-title {
  font-size: 17px;
  font-weight: 600;
  line-height: 1.24;
  letter-spacing: -0.374px;
  color: var(--color-ink);
}
.card-meta {
  font-size: 14px;
  font-weight: 400;
  line-height: 1.43;
  letter-spacing: -0.224px;
  color: var(--color-ink-muted-48);
}
.card-link {
  margin-top: 8px;
  font-size: 14px;
  font-weight: 400;
  color: var(--color-primary);
}

/* ====== 加载哨兵 ====== */
.load-sentinel { height: 1px; margin-top: 40px; }

/* ====== 空状态 ====== */
.empty-state {
  text-align: center;
  padding: 80px 22px;
}

/* ====== 统计区块 ====== */
.stats-section {
  background: var(--color-parchment);
  padding: var(--spacing-section) 22px;
  margin-top: var(--spacing-section);
}
.stats-inner {
  max-width: 980px;
  margin: 0 auto;
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 24px;
  text-align: center;
}
.stat-item { display: flex; flex-direction: column; gap: 8px; }
.stat-num {
  font-family: var(--font-display);
  font-size: 48px;
  font-weight: 600;
  line-height: 1.07;
  color: var(--color-ink);
}
.stat-label {
  font-size: 17px;
  font-weight: 400;
  color: var(--color-ink-muted-48);
}

/* ====== 页脚 ====== */
.footer {
  background: var(--color-parchment);
  padding: 64px 22px;
}
.footer-inner {
  max-width: 980px;
  margin: 0 auto;
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 32px;
}
.footer-col { display: flex; flex-direction: column; gap: 10px; }
.footer-heading {
  font-size: 14px;
  font-weight: 600;
  line-height: 1.29;
  letter-spacing: -0.224px;
  color: var(--color-ink);
  margin-bottom: 4px;
}
.footer-text {
  font-size: 17px;
  font-weight: 400;
  line-height: 2.41;
  letter-spacing: 0;
  color: var(--color-ink-muted-80);
}
.footer-legal {
  max-width: 980px;
  margin: 48px auto 0;
  border-top: 1px solid var(--color-hairline);
  padding-top: 24px;
}

/* ====== 详情遮罩 ====== */
.detail-overlay {
  position: fixed;
  top: 0; left: 0; right: 0; bottom: 0;
  background: rgba(0, 0, 0, 0.6);
  z-index: 2000;
  overflow-y: auto;
  display: flex;
  align-items: flex-start;
  justify-content: center;
  padding: 40px 22px;
}
.detail-container {
  background: var(--color-canvas);
  border-radius: var(--rounded-lg);
  max-width: 720px;
  width: 100%;
  overflow: hidden;
}
.detail-close {
  position: sticky;
  top: 12px;
  float: right;
  margin: 12px;
  z-index: 10;
  width: 44px;
  height: 44px;
  border-radius: 50%;
  background: var(--color-chip-translucent);
  border: none;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 20px;
  color: var(--color-ink);
  transition: transform 0.15s ease;
}
.detail-close:active { transform: scale(0.95); }
.detail-media-wrap {
  background: var(--color-parchment);
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 40px;
  min-height: 320px;
}
.detail-media {
  max-width: 280px;
  max-height: 280px;
  filter: drop-shadow(var(--shadow-product));
  border-radius: var(--rounded-sm);
}
.detail-content {
  padding: var(--spacing-lg);
  display: flex;
  flex-direction: column;
  gap: 20px;
}
.detail-title {
  font-family: var(--font-display);
  font-size: 34px;
  font-weight: 600;
  line-height: 1.1;
  color: var(--color-ink);
}
.detail-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}
.detail-tag {
  background: var(--color-parchment);
  border-radius: var(--rounded-pill);
  padding: 6px 14px;
  font-size: 14px;
  font-weight: 400;
  color: var(--color-ink);
}
.detail-section h3 {
  font-size: 17px;
  font-weight: 600;
  color: var(--color-ink);
  margin-bottom: 8px;
}
.detail-instructions {
  font-size: 17px;
  font-weight: 400;
  line-height: 1.47;
  color: var(--color-body);
}
.detail-steps {
  list-style: none;
  counter-reset: step;
  display: flex;
  flex-direction: column;
  gap: 12px;
}
.detail-steps li {
  counter-increment: step;
  font-size: 17px;
  font-weight: 400;
  line-height: 1.47;
  color: var(--color-body);
  padding-left: 36px;
  position: relative;
}
.detail-steps li::before {
  content: counter(step);
  position: absolute;
  left: 0;
  top: 0;
  width: 24px;
  height: 24px;
  border-radius: 50%;
  background: var(--color-primary);
  color: #fff;
  font-size: 12px;
  font-weight: 600;
  display: flex;
  align-items: center;
  justify-content: center;
}
.detail-muscles {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}
.muscle-chip {
  background: var(--color-pearl);
  border: 1px solid var(--color-divider-soft);
  border-radius: var(--rounded-sm);
  padding: 6px 12px;
  font-size: 14px;
  color: var(--color-ink-muted-80);
}

/* ====== 响应式 ====== */
@media (max-width: 1440px) {
  .grid-container { grid-template-columns: repeat(4, 1fr); }
}
@media (max-width: 1068px) {
  .grid-container { grid-template-columns: repeat(3, 1fr); }
  .hero { font-size: 40px; }
}
@media (max-width: 833px) {
  .grid-container { grid-template-columns: repeat(2, 1fr); }
  .nav-links { display: none; }
  .filter-group { gap: 6px; }
  .chip { padding: 6px 12px; font-size: 13px; }
  .search-input { min-width: 140px; }
  .stats-inner { grid-template-columns: repeat(2, 1fr); gap: 32px; }
  .footer-inner { grid-template-columns: 1fr; }
}
@media (max-width: 735px) {
  .hero-section, .stats-section { padding: 48px 22px; }
  .stat-num { font-size: 36px; }
}
@media (max-width: 640px) {
  .grid-container { grid-template-columns: 1fr; }
  .hero { font-size: 34px; }
  .lead { font-size: 21px; }
  .sub-nav-inner { flex-direction: column; align-items: stretch; }
  .filter-right { flex-direction: column; align-items: stretch; }
  .search-input { min-width: 0; width: 100%; }
  .equipment-select { width: 100%; }
  .detail-overlay { padding: 0; }
  .detail-container { border-radius: 0; min-height: 100vh; }
}
@media (max-width: 419px) {
  .hero { font-size: 28px; }
  .hero-actions { flex-direction: column; width: 100%; }
  .button-primary, .button-secondary-pill { width: 100%; }
}