/* yifanfrank.com — shared styles for every page */
:root {
  --bg: #fbfaf7;
  --surface: #ffffff;
  --text: #1d1d1f;
  --muted: #6b6b70;
  --line: #e6e3dc;
  --accent: #002147;        /* Oxford blue */
  --accent-soft: #e8edf5;
  --pill: #f1efe9;
  --radius: 14px;
  --max: 880px;
  --font: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC",
          "Hiragino Sans GB", "Microsoft YaHei", Roboto, "Helvetica Neue", Arial, sans-serif;
  --mono: ui-monospace, SFMono-Regular, Consolas, "Liberation Mono", monospace;
}
@media (prefers-color-scheme: dark) {
  :root {
    --bg: #111214;
    --surface: #1a1b1e;
    --text: #ececef;
    --muted: #9a9aa3;
    --line: #2a2b30;
    --accent: #8fb3ff;
    --accent-soft: #1d2638;
    --pill: #24252a;
  }
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: var(--font);
  font-size: 17px;
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
}
a { color: var(--accent); text-decoration: none; }
a:hover { text-decoration: underline; }
.wrap { max-width: var(--max); margin: 0 auto; padding: 0 20px; }

/* ---------- nav ---------- */
.nav {
  position: sticky; top: 0; z-index: 10;
  background: color-mix(in srgb, var(--bg) 85%, transparent);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--line);
}
.nav .wrap { display: flex; align-items: center; height: 58px; gap: 20px; }
.brand { font-weight: 700; color: var(--text); letter-spacing: -0.01em; white-space: nowrap; margin-right: auto; }
.brand:hover { text-decoration: none; }
.nav ul { display: flex; gap: 22px; list-style: none; margin: 0; padding: 0; font-size: 15px; }
.nav ul li { white-space: nowrap; }
.nav ul a { color: var(--muted); }
.nav ul a:hover, .nav ul a[aria-current="page"] { color: var(--text); text-decoration: none; }
/* language switch, far right */
.nav .lang {
  font-size: 13px; line-height: 1; padding: 6px 12px; border-radius: 999px; white-space: nowrap;
  border: 1px solid var(--line); background: var(--surface); color: var(--text);
}
.nav .lang:hover { border-color: var(--accent); text-decoration: none; }
@media (max-width: 600px) {
  /* row 1: name on the left, language switch on the right; row 2: the links */
  .nav .wrap { height: auto; padding-top: 10px; padding-bottom: 10px; flex-wrap: wrap; row-gap: 8px; }
  .nav ul { order: 3; width: 100%; gap: 16px; flex-wrap: wrap; }
}

/* ---------- hero ---------- */
.hero { padding: 72px 0 40px; }
.hero h1 { font-size: clamp(36px, 7vw, 54px); line-height: 1.1; margin: 0 0 12px; letter-spacing: -0.03em; }
.hero .role { font-size: 20px; color: var(--muted); margin: 0 0 22px; }
.hero .lead { max-width: 640px; margin: 0 0 26px; }
.links { display: flex; flex-wrap: wrap; gap: 10px; }
.btn {
  display: inline-block; padding: 8px 16px; border-radius: 999px;
  border: 1px solid var(--line); background: var(--surface); color: var(--text); font-size: 15px;
}
.btn:hover { border-color: var(--accent); text-decoration: none; }
.btn.primary { background: var(--accent); border-color: var(--accent); color: var(--bg); }

/* ---------- sections ---------- */
section { padding: 36px 0; border-top: 1px solid var(--line); }
section h2 {
  font-size: 13px; text-transform: uppercase; letter-spacing: 0.12em;
  color: var(--muted); margin: 0 0 22px; font-weight: 600;
}
.item { display: grid; grid-template-columns: 1fr auto; gap: 4px 20px; margin-bottom: 22px; }
.item h3 { margin: 0; font-size: 18px; }
.item .when { color: var(--muted); font-size: 15px; white-space: nowrap; font-variant-numeric: tabular-nums; }
.item .sub { grid-column: 1 / -1; color: var(--muted); margin: 0; font-size: 15px; }
.item ul { grid-column: 1 / -1; margin: 6px 0 0; padding-left: 20px; }
.item li { margin: 2px 0; }
@media (max-width: 600px) { .item { grid-template-columns: 1fr; } }

.awards { list-style: none; padding: 0; margin: 0; }
.awards li { padding: 8px 0; border-bottom: 1px dashed var(--line); display: flex; justify-content: space-between; gap: 16px; }
.awards li:last-child { border-bottom: 0; }
.awards span { color: var(--muted); font-size: 15px; white-space: nowrap; }

/* ---------- cards ---------- */
.cards { display: grid; grid-template-columns: repeat(auto-fill, minmax(250px, 1fr)); gap: 16px; }
.card {
  background: var(--surface); border: 1px solid var(--line); border-radius: var(--radius);
  padding: 20px; display: flex; flex-direction: column; gap: 8px; color: var(--text);
}
a.card:hover { border-color: var(--accent); text-decoration: none; transform: translateY(-1px); }
.card h3 { margin: 0; font-size: 17px; }
.card p { margin: 0; color: var(--muted); font-size: 15px; flex: 1; }
.tags { display: flex; flex-wrap: wrap; gap: 6px; }
.tag { font-size: 12px; background: var(--pill); color: var(--muted); padding: 2px 9px; border-radius: 999px; }

/* ---------- site index ---------- */
.index { list-style: none; padding: 0; margin: 0; border: 1px solid var(--line); border-radius: var(--radius); overflow: hidden; background: var(--surface); }
.index li { display: grid; grid-template-columns: 130px 1fr auto; gap: 16px; align-items: center; padding: 14px 18px; border-bottom: 1px solid var(--line); }
.index li:last-child { border-bottom: 0; }
.index code { font-family: var(--mono); font-size: 14px; }
.index .desc { color: var(--muted); font-size: 15px; }
.status { font-size: 12px; padding: 2px 10px; border-radius: 999px; white-space: nowrap; }
.status.live { background: #dcf5e3; color: #1a6b35; }
.status.soon { background: var(--pill); color: var(--muted); }
@media (prefers-color-scheme: dark) { .status.live { background: #173823; color: #7fdc9c; } }
@media (max-width: 600px) { .index li { grid-template-columns: 1fr auto; } .index .desc { grid-column: 1 / -1; } }

.skills { display: grid; grid-template-columns: 140px 1fr; gap: 10px 20px; margin: 0; }
.skills dt { color: var(--muted); font-size: 15px; }
.skills dd { margin: 0; }
@media (max-width: 600px) { .skills { grid-template-columns: 1fr; } .skills dd { margin-bottom: 8px; } }

/* ---------- sub-page header + placeholder ---------- */
.page-head { padding: 64px 0 28px; }
.page-head h1 { font-size: clamp(32px, 6vw, 44px); margin: 0 0 10px; letter-spacing: -0.02em; }
.page-head p { color: var(--muted); margin: 0; max-width: 620px; }
.soon-box {
  border: 1px dashed var(--line); border-radius: var(--radius); padding: 28px;
  text-align: center; color: var(--muted); background: var(--surface);
}
.soon-box strong { color: var(--text); display: block; font-size: 18px; margin-bottom: 4px; }

footer { border-top: 1px solid var(--line); padding: 28px 0 48px; color: var(--muted); font-size: 14px; margin-top: 24px; }
footer .wrap { display: flex; justify-content: space-between; flex-wrap: wrap; gap: 10px; }