/* Bridge AI — exam prep site
   Plain CSS. No build step, no CDN, no web fonts, no JavaScript.
   Every page links this file with a relative path, so the folder can be
   dropped anywhere. Each page may override the brand tokens in its own
   <style> block (see aiio.html and friends). */

:root {
  color-scheme: light;

  /* neutral base — app pages override the brand/bg/surface group */
  --brand: #3E4A57;
  --brand-dark: #2D3742;
  --brand-light: #5E6D7C;
  --brand-wash: #EDF0F2;
  --on-brand: #FFFFFF;

  --bg: #F7F8F8;
  --surface: #FFFFFF;
  --surface-2: #EFF1F2;
  --border: #DCE0E3;

  --text: #171A16;
  --text-dim: #5B6357;

  --radius: 14px;
  --radius-sm: 10px;
  --font: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto,
          "Helvetica Neue", Arial, "Hiragino Sans", "Noto Sans JP", sans-serif;
  --mono: ui-monospace, SFMono-Regular, Menlo, Consolas, "Liberation Mono", monospace;
}

@media (prefers-color-scheme: dark) {
  :root {
    color-scheme: dark;

    --brand: #9BAAB8;
    --brand-dark: #7C8C9A;
    --brand-light: #B8C5D0;
    --brand-wash: #1C2126;
    --on-brand: #11151A;

    --bg: #101315;
    --surface: #171B1E;
    --surface-2: #1F2428;
    --border: #2C3338;

    --text: #ECEFE8;
    --text-dim: #A6AE9C;
  }
}

*, *::before, *::after { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: var(--font);
  font-size: 17px;
  line-height: 1.7;
  overflow-wrap: break-word;
}

.wrap { max-width: 760px; margin: 0 auto; padding: 0 20px; }

a { color: var(--brand-dark); }
@media (prefers-color-scheme: dark) { a { color: var(--brand); } }
a:hover { text-decoration: none; }

/* ---------- header / footer ---------- */

.site-head { background: var(--surface); border-bottom: 1px solid var(--border); }
.site-head .wrap {
  display: flex; flex-wrap: wrap; align-items: center;
  gap: 6px 20px; padding-top: 13px; padding-bottom: 13px;
}
.brand {
  font-weight: 700; font-size: 18px; letter-spacing: -.01em;
  text-decoration: none; color: var(--text); white-space: nowrap;
}
.brand span { color: var(--brand-dark); }
@media (prefers-color-scheme: dark) { .brand span { color: var(--brand); } }
.site-head nav {
  display: flex; flex-wrap: wrap; gap: 4px 16px;
  margin-left: auto; font-size: 15px;
}

.site-foot {
  border-top: 1px solid var(--border);
  margin-top: 46px; padding: 22px 0 44px;
  color: var(--text-dim); font-size: 14px;
}
.site-foot nav { display: flex; flex-wrap: wrap; gap: 4px 16px; margin-bottom: 10px; }
.site-foot p { margin: 6px 0; }

/* ---------- text ---------- */

h1 {
  font-size: clamp(27px, 6.2vw, 38px); line-height: 1.22;
  letter-spacing: -.02em; margin: 32px 0 10px;
}
h2 { font-size: clamp(20px, 4.4vw, 24px); line-height: 1.3; margin: 40px 0 10px; }
h3 { font-size: clamp(17px, 3.8vw, 19px); line-height: 1.4; margin: 26px 0 6px; }
.card h2, .card h3 { margin-top: 0; }

.lead {
  font-size: clamp(17px, 3.5vw, 19px);
  color: var(--text-dim); margin: 0 0 22px;
}
p { margin: 0 0 14px; }
ul, ol { padding-left: 22px; margin: 0 0 16px; }
li { margin: 6px 0; }
code {
  font-family: var(--mono); font-size: .92em;
  background: var(--surface-2); border-radius: 5px; padding: 1px 5px;
}
hr { border: 0; border-top: 1px solid var(--border); margin: 34px 0; }

/* ---------- blocks ---------- */

.card {
  background: var(--surface); border: 1px solid var(--border);
  border-radius: var(--radius); padding: 18px 20px; margin: 18px 0;
}
.card > :last-child { margin-bottom: 0; }

.note {
  background: var(--surface-2); border-radius: var(--radius);
  padding: 15px 18px; color: var(--text-dim); font-size: 15px;
  margin: 18px 0;
}
.note > :last-child { margin-bottom: 0; }
.note b { color: var(--text); }

.tag {
  display: inline-block; background: var(--brand-wash); color: var(--brand-dark);
  border-radius: 999px; padding: 3px 12px; font-size: 14px; font-weight: 600;
  margin: 0 6px 8px 0;
}
@media (prefers-color-scheme: dark) { .tag { color: var(--brand); } }

.soon {
  display: inline-block; border: 1px dashed var(--border); color: var(--text-dim);
  border-radius: 999px; padding: 2px 11px; font-size: 13px; font-weight: 600;
  margin: 0 6px 8px 0;
}

/* key / value facts */
.facts { list-style: none; padding: 0; margin: 0; }
.facts li {
  display: flex; flex-wrap: wrap; gap: 2px 12px;
  padding: 9px 0; border-bottom: 1px solid var(--border);
}
.facts li:last-child { border-bottom: 0; }
.facts b { min-width: 8.5em; font-weight: 600; }
.facts span { color: var(--text-dim); flex: 1 1 14em; }

/* ---------- app cards on the index ---------- */

.apps { display: grid; gap: 16px; margin: 22px 0 8px; }

.app {
  background: var(--surface);
  border: 1px solid var(--border);
  border-left: 5px solid var(--accent, var(--brand));
  border-radius: var(--radius);
  padding: 17px 19px;
}
.app h2 { margin: 0 0 2px; font-size: clamp(19px, 4.2vw, 22px); }
.app h2 a { color: var(--text); text-decoration: none; }
.app h2 a:hover { text-decoration: underline; }
.app .exam {
  font-weight: 600; color: var(--accent-ink, var(--brand-dark));
  font-size: 15px; letter-spacing: .01em; margin: 0 0 6px;
}
.app .sub { color: var(--text-dim); font-size: 15px; margin: 0 0 10px; }
.app ul { margin-bottom: 12px; }
.app .more { font-weight: 600; }

.spec {
  list-style: none; display: flex; flex-wrap: wrap;
  gap: 6px 8px; padding: 0; margin: 0 0 12px;
}
.spec li {
  margin: 0; font-size: 14px; font-weight: 600;
  background: var(--surface-2); border-radius: 999px; padding: 3px 11px;
  color: var(--text-dim);
}

/* ---------- domain table (app pages) ---------- */

.doms { list-style: none; padding: 0; margin: 16px 0 18px; }
.doms li {
  padding: 13px 0; border-bottom: 1px solid var(--border); margin: 0;
}
.doms li:last-child { border-bottom: 0; }
.doms .row {
  display: flex; flex-wrap: wrap; align-items: baseline; gap: 2px 10px;
}
.doms .name { font-weight: 600; flex: 1 1 12em; }
.doms .share {
  font-size: 14px; color: var(--text-dim); font-variant-numeric: tabular-nums;
  white-space: nowrap;
}
.doms .meter {
  height: 5px; border-radius: 99px; background: var(--surface-2);
  margin: 7px 0 7px; overflow: hidden;
}
.doms .meter i { display: block; height: 100%; background: var(--brand); border-radius: 99px; }
.doms p { margin: 0; color: var(--text-dim); font-size: 15px; }

/* ---------- misc ---------- */

.mail {
  font-family: var(--mono); font-size: 17px; font-weight: 600;
  background: var(--brand-wash); border-radius: var(--radius-sm);
  padding: 10px 14px; display: inline-block; margin: 0 0 14px;
}
.backlink { font-size: 15px; margin: 26px 0 0; }

@media (max-width: 430px) {
  body { font-size: 16px; }
  .wrap { padding: 0 16px; }
  .card { padding: 16px 16px; }
  .app { padding: 15px 15px; }
  .facts b { min-width: 100%; }
  .site-head .wrap { padding-top: 11px; padding-bottom: 11px; }
}