/* ============================================
   Global — Apple 极简风格
   ============================================ */

:root {
  /* ── 颜色 ── */
  --color-bg: #000000;
  --color-surface: #0a0a0a;
  --color-surface-raised: #111111;
  --color-text: #f5f5f7;
  --color-text-secondary: #86868b;
  --color-text-tertiary: #6e6e73;
  --color-border: rgba(255, 255, 255, 0.08);
  --color-border-hover: rgba(255, 255, 255, 0.16);
  --color-glass: rgba(255, 255, 255, 0.03);
  --color-glass-hover: rgba(255, 255, 255, 0.06);

  /* ── 排版 — Apple 风格: 全 sans-serif ── */
  --font-sans: "Helvetica Neue", "PingFang SC", -apple-system, BlinkMacSystemFont, "SF Pro Text", sans-serif;
  --font-display: "Helvetica Neue", "PingFang SC", -apple-system, BlinkMacSystemFont, "SF Pro Display", sans-serif;

  --text-display: clamp(3.5rem, 7vw, 6.5rem);
  --text-h1: clamp(2.2rem, 3.5vw, 3.5rem);
  --text-h2: clamp(1.6rem, 2.5vw, 2.4rem);
  --text-h3: clamp(1.15rem, 1.6vw, 1.5rem);
  --text-body: 1rem;
  --text-small: 0.875rem;
  --text-caption: 0.75rem;

  --leading-tight: 1.12;
  --leading-normal: 1.6;

  --tracking-display: -0.03em;
  --tracking-tight: -0.02em;
  --tracking-normal: 0;
  --tracking-wide: 0.04em;
  --tracking-wider: 0.08em;

  /* ── 圆角 ── */
  --radius-sm: 6px;
  --radius-md: 10px;
  --radius-lg: 18px;
  --radius-xl: 28px;

  /* ── 间距 ── */
  --space-1: 4px;   --space-2: 8px;   --space-3: 12px;
  --space-4: 16px;  --space-5: 24px;  --space-6: 32px;
  --space-7: 48px;  --space-8: 64px;  --space-9: 80px;
  --space-10: 120px; --space-11: 160px;

  /* ── 导航 ── */
  --nav-height: 52px;  /* Apple 风格更窄的导航 */

  /* ── 动画 ── */
  --ease-apple: cubic-bezier(0.25, 0.1, 0.25, 1);
  --ease-spring: cubic-bezier(0.3, 1.2, 0.5, 1);
  --duration-fast: 200ms;
  --duration-base: 400ms;
  --duration-slow: 700ms;

  /* ── Z-index ── */
  --z-nav: 100;
}

/* ── 基础 ── */
body {
  font-family: var(--font-sans);
  font-size: var(--text-body);
  line-height: var(--leading-normal);
  color: var(--color-text);
  background: var(--color-bg);
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
  font-weight: 400;
}

/* ── 排版 ── */
.display {
  font-family: var(--font-display);
  font-size: var(--text-display);
  line-height: var(--leading-tight);
  letter-spacing: var(--tracking-display);
  font-weight: 600;
}

h1, .h1 {
  font-family: var(--font-display);
  font-size: var(--text-h1);
  line-height: var(--leading-tight);
  letter-spacing: var(--tracking-tight);
  font-weight: 600;
}

h2, .h2 {
  font-family: var(--font-display);
  font-size: var(--text-h2);
  line-height: var(--leading-tight);
  letter-spacing: var(--tracking-tight);
  font-weight: 600;
}

h3, .h3 {
  font-size: var(--text-h3);
  line-height: var(--leading-tight);
  font-weight: 500;
}

.text-secondary { color: var(--color-text-secondary); }
.text-tertiary  { color: var(--color-text-tertiary); }
.text-caption   { font-size: var(--text-caption); letter-spacing: var(--tracking-wider); text-transform: uppercase; font-weight: 500; }

/* ── 布局 ── */
.container {
  width: 100%;
  max-width: 1200px;
  margin-inline: auto;
  padding-inline: var(--space-6);
}

.section {
  padding-block: var(--space-10);
  position: relative;
}

.fullscreen {
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  position: relative;
  overflow: hidden;
}

.grid-2 { display: grid; grid-template-columns: 1fr 1fr; gap: var(--space-8); align-items: center; }
.grid-4 { display: grid; grid-template-columns: repeat(4, 1fr); gap: var(--space-5); }

/* ── Section 分隔线 ── */
.section-divider::before {
  content: '';
  position: absolute;
  top: 0;
  left: 50%;
  transform: translateX(-50%);
  width: 40px;
  height: 1px;
  background: rgba(255,255,255,0.1);
}

/* ── 渐入动画 ── */
.reveal {
  opacity: 0;
  transform: translateY(48px);
  transition: opacity var(--duration-slow) var(--ease-apple),
              transform var(--duration-slow) var(--ease-apple);
}

.reveal.visible {
  opacity: 1;
  transform: translateY(0);
}

/* ── 图片 ── */
.img-cover {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.img-blur-load {
  filter: blur(20px);
  transform: scale(1.06);
  transition: filter 0.7s ease, transform 0.7s ease;
}

.img-blur-load.loaded {
  filter: blur(0);
  transform: scale(1);
}

/* ── 链接 ── */
.link-underline {
  position: relative;
  display: inline-flex;
  align-items: center;
  gap: 4px;
  font-size: var(--text-small);
  letter-spacing: var(--tracking-wide);
  padding-bottom: 2px;
  transition: gap var(--duration-fast) var(--ease-apple);
}

.link-underline::after {
  content: '';
  position: absolute;
  left: 0;
  bottom: 0;
  width: 0;
  height: 1px;
  background: var(--color-text);
  transition: width var(--duration-base) var(--ease-apple);
}

.link-underline:hover { gap: 8px; }
.link-underline:hover::after { width: 100%; }

/* ── 标签 ── */
.tag {
  display: inline-block;
  padding: 3px 10px;
  border: 1px solid var(--color-border);
  border-radius: 100px;
  font-size: var(--text-caption);
  letter-spacing: var(--tracking-wider);
  color: var(--color-text-secondary);
  text-transform: uppercase;
  transition: border-color var(--duration-fast) ease, color var(--duration-fast) ease;
}

.tag:hover { border-color: var(--color-text-secondary); color: var(--color-text); }

/* ── 滚动条 ── */
::-webkit-scrollbar { width: 3px; }
::-webkit-scrollbar-track { background: transparent; }
::-webkit-scrollbar-thumb { background: rgba(255,255,255,0.08); border-radius: 2px; }

::selection { background: rgba(255,255,255,0.15); color: #fff; }