/* ============================================================
   maCher Chan® — Global Stylesheet
   全站唯一的 @font-face 声明、CSS 变量、Reset、导航通用样式
   ============================================================ */

/* ---------- Font ---------- */
@font-face {
  font-family: 'HelveticaNeue93BlackExt';
  src: url('../assets/fonts/HelveticaNeue93BlackExt.otf') format('opentype');
  font-weight: 100 900;
  font-style: normal;
  font-display: swap;
}

/* ---------- Design Tokens ---------- */
:root {
  /* 品牌色 */
  --brand-blue: #146EF5;

  /* 背景 */
  --bg-primary: #F4F4F5;

  /* 文字 */
  --text-primary: #1c1c1e;
  --text-secondary: rgba(0,0,0,0.4);
  --text-nav: #000000;

  /* 品牌元素 */
  --brand-logo: #146EF5;
  --brand-title: #146EF5;

  /* 字体 */
  --font-brand: 'HelveticaNeue93BlackExt', 'Helvetica Neue', Arial, sans-serif;
  --font-cn: 'Microsoft YaHei', sans-serif;

  /* 字距 */
  --tracking-brand: -0.077em;
  --tracking-nav: -0.023em;
}

/* ---------- Reset ---------- */
*, *::before, *::after {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

body {
  background: var(--bg-primary);
}

a {
  color: inherit;
  text-decoration: none;
}

img {
  display: block;
  max-width: 100%;
}

/* ---------- Navigation (all pages) ---------- */
/* 使用方式：<nav class="nav"><a class="nav-logo" href="index.html">maCher Chan®</a><div class="nav-links"><a href="...">PROJECTS</a>...</div></nav> */
.nav {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 100;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 60px;
  height: 70px;
  background: transparent;
}

.nav-logo {
  font-family: var(--font-brand);
  letter-spacing: var(--tracking-brand);
  color: var(--brand-logo);
}

.nav-links {
  display: flex;
  gap: 32px;
  list-style: none;
}

.nav-links a {
  font-family: var(--font-brand);
  font-size: 14px;
  letter-spacing: var(--tracking-nav);
  color: var(--text-nav);
  position: relative;
}

.nav-links a::after {
  content: '';
  position: absolute;
  bottom: -2px;
  left: 0;
  right: 0;
  height: 1px;
  background: var(--text-nav);
  transform: scaleX(0);
  transform-origin: left;
  transition: transform 0.2s ease;
}

.nav-links a:hover::after,
.nav-links a.active::after {
  transform: scaleX(1);
}

/* ─── Mobile (≤ 768px) ──────────────────────────────────── */
@media (max-width: 768px) {
  .nav {
    padding: 0 20px;
    height: 56px;
  }
  .nav-logo {
    font-size: 13px;
  }
  .nav-links {
    gap: 14px;
  }
  .nav-links a {
    font-size: 11px;
    white-space: nowrap;
  }
}