/* 与 byteon.cc.cd 同一套设计语言(取自其 styles.css 的设计变量) */
:root {
  --ink: #101113;
  --paper: #f5f6f4;
  --white: #ffffff;
  --line: #c7cbc7;
  --muted: #5d625f;
  --red: #ef4938;
  --green: #4eb879;
  --blue: #4a84e8;
  --yellow: #e6b72f;
  --shell: min(1240px, calc(100% - 64px));
}

* { box-sizing: border-box; }

html { -webkit-text-size-adjust: 100%; }

body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font-family: Inter, "Helvetica Neue", Arial, sans-serif;
  font-size: 17px;
  line-height: 1.55;
  -webkit-font-smoothing: antialiased;
}

a { color: inherit; }

.shell { width: var(--shell); margin-inline: auto; }

.skip-link {
  position: absolute; left: -9999px; top: 0;
  background: var(--ink); color: var(--paper);
  padding: 12px 18px; z-index: 99;
}
.skip-link:focus { left: 12px; top: 12px; }

/* ---------- header ---------- */
.site-header {
  display: flex; align-items: center; justify-content: space-between;
  padding: 26px 0;
  border-bottom: 1px solid var(--line);
}
.brand {
  font-weight: 600; letter-spacing: -0.02em;
  font-size: 19px; text-decoration: none;
}
.brand span { color: var(--muted); font-weight: 400; }
.site-nav { display: flex; gap: 26px; font-size: 15px; }
.site-nav a { color: var(--muted); text-decoration: none; }
.site-nav a:hover { color: var(--ink); }

/* ---------- hero ---------- */
.hero { padding: 96px 0 84px; border-bottom: 1px solid var(--line); }
.eyebrow {
  margin: 0 0 30px;
  font-size: 13px; letter-spacing: 0.14em; text-transform: uppercase;
  color: var(--muted);
}
.hero h1 {
  margin: 0;
  font-size: clamp(38px, 6.4vw, 78px);
  line-height: 1.02; letter-spacing: -0.035em; font-weight: 600;
  max-width: 17ch;
}
.hero p.lede {
  margin: 30px 0 0; max-width: 56ch;
  font-size: clamp(17px, 1.7vw, 21px); color: var(--muted);
}

/* ---------- sections ---------- */
.section { padding: 76px 0; border-bottom: 1px solid var(--line); }
.section-index {
  margin: 0 0 34px;
  font-size: 13px; letter-spacing: 0.14em; text-transform: uppercase;
  color: var(--muted);
}
.section h2 {
  margin: 0 0 22px;
  font-size: clamp(27px, 3.4vw, 40px);
  line-height: 1.1; letter-spacing: -0.025em; font-weight: 600;
  max-width: 20ch;
}
.section p { margin: 0 0 16px; max-width: 62ch; color: var(--muted); }

/* ---------- cards ---------- */
.grid { display: grid; gap: 1px; background: var(--line); border: 1px solid var(--line); }
@media (min-width: 720px) { .grid { grid-template-columns: repeat(2, 1fr); } }
@media (min-width: 1040px) { .grid.g3 { grid-template-columns: repeat(3, 1fr); } }

.card { background: var(--white); padding: 30px 28px 34px; display: block; text-decoration: none; }
.card .k {
  font-size: 12px; letter-spacing: 0.14em; text-transform: uppercase;
  color: var(--muted); display: flex; align-items: center; gap: 9px;
}
.card .k::before { content: ""; width: 9px; height: 9px; border-radius: 50%; background: var(--line); }
.card.c-red    .k::before { background: var(--red); }
.card.c-green  .k::before { background: var(--green); }
.card.c-blue   .k::before { background: var(--blue); }
.card.c-yellow .k::before { background: var(--yellow); }
.card h3 { margin: 18px 0 10px; font-size: 21px; letter-spacing: -0.02em; font-weight: 600; }
.card p { margin: 0; font-size: 15.5px; color: var(--muted); max-width: none; }

/* ---------- statement ---------- */
.statement { padding: 84px 0; border-bottom: 1px solid var(--line); }
.statement p {
  margin: 0; max-width: 24ch;
  font-size: clamp(28px, 4vw, 48px);
  line-height: 1.12; letter-spacing: -0.03em; color: var(--ink); font-weight: 600;
}

/* ---------- footer ---------- */
.site-footer {
  padding: 40px 0 56px;
  display: flex; flex-wrap: wrap; gap: 18px;
  align-items: center; justify-content: space-between;
  font-size: 14px; color: var(--muted);
}
.site-footer a { color: var(--muted); text-decoration: none; }
.site-footer a:hover { color: var(--ink); }
.footer-links { display: flex; gap: 22px; flex-wrap: wrap; }

/* ---------- misc ---------- */
.mono {
  font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  font-size: 14px;
}
.note {
  margin-top: 30px; padding: 16px 18px;
  border: 1px solid var(--line); background: var(--white);
  font-size: 14.5px; color: var(--muted); max-width: 62ch;
}

@media (max-width: 640px) {
  :root { --shell: calc(100% - 32px); }
  .hero { padding: 66px 0 56px; }
  .section { padding: 54px 0; }
  .site-nav { gap: 16px; font-size: 14px; }
}