/* ─── Reset ─────────────────────────────────────────────────── */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; }

/* ─── Primitive Tokens ───────────────────────────────────────── */
:root {
  --color-black:  #000000;
  --color-white:  #ffffff;
  --color-silver: #a6a6a6;
  --color-blue:   #0099ff;
}

/* ─── Semantic Tokens: Dark (default) ───────────────────────── */
:root,.container
[data-theme="dark"] {
  --bg:           var(--color-black);
  --fg:           var(--color-white);
  --fg-secondary: var(--color-silver);
  --fg-thirdary:  rgb(154, 154, 154);
  --fg-body:      rgba(200, 200, 200, 0.8);
  --surface:      rgba(157, 157, 157, 0.04);
  --surface-dark: rgba(255, 255, 255, 0.02);
  --border:       rgba(255, 255, 255, 0.08);
  --nav-bg:       rgba(0, 0, 0, 0.88);
  --blue:         var(--color-blue);
  --blue-ring:    rgba(0, 153, 255, 0.18);
  --blue-surface: rgba(0, 153, 255, 0.05);
}

/* ─── Semantic Tokens: Light ─────────────────────────────────── */
[data-theme="light"] {
  --bg:           var(--color-white);
  --fg:           var(--color-black);
  --fg-secondary: #6b6b6b;
  --fg-body:      rgba(0, 0, 0, 0.75);
  --surface:      rgba(0, 0, 0, 0.04);
  --surface-dark: rgba(0, 0, 0, 0.08);
  --border:       rgba(0, 0, 0, 0.1);
  --nav-bg:       rgba(255, 255, 255, 0.88);
  --blue:         var(--color-blue);
  --blue-ring:    rgba(0, 153, 255, 0.18);
  --blue-surface: rgba(0, 153, 255, 0.08);
}

/* ─── Layout Tokens ──────────────────────────────────────────── */
:root {
  --max-w:       1280px;
  --section-gap: 130px;
}

/* ─── Base ───────────────────────────────────────────────────── */
body {
  background: var(--bg);
  color: var(--fg);
  font-family: 'Inter', -apple-system, system-ui, sans-serif;
  font-size: 16px;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
}
a { color: inherit; text-decoration: none; }
img { display: block; max-width: 100%; }

/* ─── Container ──────────────────────────────────────────────── */
.container {
  max-width: var(--max-w);
  margin: 0 auto;
  padding: 0 40px;
}

/* ─── Nav ────────────────────────────────────────────────────── */
nav {
  position: fixed;
  top: 0; left: 0; right: 0;
  z-index: 100;
  background: var(--nav-bg);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  border-bottom: 1px solid var(--border);
}
.nav-inner {
  max-width: var(--max-w);
  margin: 0 auto;
  padding: 0 40px;
  height: 60px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}
.nav-left { display: flex; align-items: center; gap: 20px; }
.nav-back {
  font-size: 13px; font-weight: 500;
  color: var(--fg-secondary); letter-spacing: -0.1px;
  transition: color 0.2s; white-space: nowrap;
}
.nav-back:hover { color: var(--fg); }
.nav-sep { width: 1px; height: 16px; background: var(--border); flex-shrink: 0; }
.nav-brand { display: flex; align-items: center; gap: 12px; }
.nav-line { display: block; width: 36px; height: 1.5px; background: var(--fg); flex-shrink: 0; }
.nav-name {
  font-family: 'Space Grotesk', sans-serif;
  font-weight: 600; font-size: 18px; letter-spacing: -0.4px; color: var(--fg);
}
.nav-links { display: flex; align-items: center; gap: 28px; }
.nav-links a {
  font-size: 14px; font-weight: 400; color: var(--fg-secondary);
  letter-spacing: -0.1px; transition: color 0.2s;
}
.nav-links a:hover { color: var(--fg); }
.nav-pill {
  border: 1px solid rgba(255,255,255,0.2) !important;
  border-radius: 100px !important; padding: 5px 18px !important;
  color: var(--fg) !important; transition: background 0.2s !important;
}
.nav-pill:hover { background: rgba(255,255,255,0.07) !important; }

/* ─── Project Section ────────────────────────────────────────── */
.project { padding-top: 120px; padding-bottom: var(--section-gap); }
.project-header { margin-bottom: 56px; }
.project-index {
  font-size: 12px; font-weight: 500; letter-spacing: 0.12em;
  text-transform: uppercase; color: var(--fg-secondary); margin-bottom: 16px; opacity: 0.6;
}
.project-title {
  font-family: 'Space Grotesk', sans-serif;
  font-weight: 600; font-size: clamp(42px, 5vw, 64px);
  line-height: 1.0; letter-spacing: clamp(-1.5px, -0.035em, -2.5px);
  color: var(--fg); margin-bottom: 20px;
}
.project-tags { display: flex; flex-wrap: wrap; gap: 8px; }
.tag {
  display: inline-block; font-size: 12px; font-weight: 500;
  color: var(--fg-secondary); background: var(--surface);
  border: 1px solid var(--border); border-radius: 100px;
  padding: 4px 12px; letter-spacing: 0.01em;
}

/* ─── Project Grid ───────────────────────────────────────────── */
.project-body { display: grid; grid-template-columns: 340px 1fr; gap: 80px; align-items: start; }
.project-meta-col { position: sticky; top: 90px; }
.meta-block { margin-bottom: 36px; }
.meta-label {
  font-size: 11px; font-weight: 600; letter-spacing: 0.1em;
  text-transform: uppercase; color: var(--fg-secondary); opacity: 0.5; margin-bottom: 8px;
}
.case-label {
  display: block;
  font-size: 11px;
  font-weight: 600;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--blue);
  line-height: 18px;
  margin-bottom: 12px;
}
.case-heading {
  display: block;
  font-family: 'Space Grotesk', sans-serif;
  font-weight: 600;
  font-size: clamp(26px, 2.8vw, 38px);
  line-height: 1.05;
  letter-spacing: -0.5px;
  color: var(--fg);
  margin-bottom: 20px;
}
.case-subheading {
  font-family: 'Space Grotesk', sans-serif;
  font-size: 17px; font-weight: 600;
  letter-spacing: -0.2px; color: var(--fg);
  margin-top: 40px; margin-bottom: 14px;
}
.case-subheading:first-child { margin-top: 0; }

.case-body {
  font-size: 15px;
  color: var(--fg-body);   /* 对应 old 的 rgba(255,255,255,0.62) */
  line-height: 1.8;
  margin-bottom: 18px;
}
.case-body:last-child { margin-bottom: 0; }
.case-body strong { color: var(--fg); font-weight: 600; }
.meta-text { font-size: 13px; color: var(--fg); line-height: 1.6; }

/* ─── Timeline ───────────────────────────────────────────────── */
.timeline { display: flex; flex-direction: column; gap: 0; }
.timeline-item { display: flex; align-items: flex-start; gap: 14px; position: relative; }
.timeline-item:not(:last-child)::after {
  content: ''; position: absolute;
  left: 5px; top: 14px; bottom: -20px;
  width: 1px; background: var(--border);
}
.timeline-dot {
  width: 11px; height: 11px; border-radius: 50%;
  background: var(--border); border: 1.5px solid var(--fg-secondary);
  flex-shrink: 0; margin-top: 4px;
}
.timeline-content { padding-bottom: 20px; }
.timeline-date {
  font-size: 11px; font-weight: 600; letter-spacing: 0.06em;
  text-transform: uppercase; color: var(--blue); margin-bottom: 2px;
}
.timeline-milestone { font-size: 13px; color: var(--fg-secondary); }

/* ─── Design Statement ───────────────────────────────────────── */
.design-statement {
  border-left: 2px solid var(--blue);
  padding-left: 24px;
  margin-bottom: 56px;
}
.design-statement p {
  font-size: 17px; font-style: italic;
  color: var(--fg-body);
  line-height: 1.75; letter-spacing: -0.1px;
}
.design-statement p + p { margin-top: 20px; }

/* ─── Statement Label ────────────────────────────────────────── */
.statement-label {
  font-size: 11px; font-weight: 600;
  letter-spacing: 0.1em; text-transform: uppercase;
  color: var(--blue); opacity: 0.8; margin-bottom: 16px;
}

/* ─── Project Result ─────────────────────────────────────────── */
.project-result {
  margin-top: 40px; font-size: 14px; color: var(--fg-secondary);
  border-left: 2px solid var(--border);
  padding-left: 16px; line-height: 1.6;
}

/* ─── Footer ─────────────────────────────────────────────────── */
footer { border-top: 1px solid var(--border); padding: 64px 0 48px; }
.footer-inner { display: flex; justify-content: space-between; align-items: flex-start; margin-bottom: 48px; }
.footer-left .footer-name {
  font-family: 'Space Grotesk', sans-serif;
  font-weight: 600; font-size: 20px;
  letter-spacing: -0.5px; color: var(--fg); margin-bottom: 6px;
}
.footer-left .footer-role { font-size: 14px; color: var(--fg-secondary); }
.footer-links { display: flex; flex-direction: column; align-items: flex-end; gap: 10px; }
.footer-link {
  font-size: 14px; color: var(--fg-secondary);
  transition: color 0.2s; display: flex; align-items: center; gap: 8px;
}
.footer-link:hover { color: var(--fg); }
.footer-link .link-label {
  font-size: 11px; font-weight: 600;
  letter-spacing: 0.08em; text-transform: uppercase;
  color: var(--fg-secondary); opacity: 0.4;
  min-width: 56px; text-align: right;
}
.footer-copy { font-size: 12px; color: var(--fg-secondary); opacity: 0.35; }

/* ─── Responsive ─────────────────────────────────────────────── */
@media (max-width: 900px) {
  :root { --section-gap: 80px; }
  .container { padding: 0 24px; }
  .nav-inner  { padding: 0 24px; }
  .project-body { grid-template-columns: 1fr; gap: 48px; }
  .project-meta-col { position: static; }
  .footer-inner { flex-direction: column; gap: 40px; }
  .footer-links { align-items: flex-start; }
  .footer-link .link-label { text-align: left; }
}
@media (max-width: 560px) {
  :root { --section-gap: 64px; }
  .nav-links { gap: 18px; }
  .nav-links a:first-child { display: none; }
  .nav-back { display: none; }
  .nav-sep  { display: none; }
}