/* One hand-written stylesheet. No framework, no CDN, no web fonts.
   Pages should land near 30 KB, against the 635 KB the old Medium exports
   shipped (DESIGN.md 8). */

:root {
  --bg: #fdfdfc;
  --fg: #1c1c1a;
  --muted: #5f5f58;
  --rule: #e2e0d8;
  --accent: #1f5f8b;
  --accent-soft: #eaf2f8;
  --code-bg: #f5f4ef;
  --green: #1c6b3c;
  --green-bg: #e6f3ea;
  --red: #9b2226;
  --red-bg: #fbe9e9;
  --amber: #7a5a00;
  --amber-bg: #fdf3d8;
  --measure: 68ch;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #16161a;
    --fg: #e8e6e1;
    --muted: #a3a099;
    --rule: #32323a;
    --accent: #7fb8de;
    --accent-soft: #1d2b36;
    --code-bg: #1e1e24;
    --green: #7fce9f;
    --green-bg: #16291d;
    --red: #f0918f;
    --red-bg: #2c1718;
    --amber: #e5c05c;
    --amber-bg: #2b2413;
  }
}

* { box-sizing: border-box; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--fg);
  font: 16px/1.65 -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto,
        "Helvetica Neue", Arial, sans-serif;
}

a { color: var(--accent); }
a:hover { text-decoration: underline; }

.skip {
  position: absolute; left: -9999px;
}
.skip:focus {
  left: 0; top: 0; padding: .6rem 1rem; background: var(--accent); color: #fff; z-index: 10;
}

/* ---------------------------------------------------------------- topbar */

.topbar {
  display: flex; align-items: center; justify-content: space-between;
  gap: 1rem; flex-wrap: wrap;
  padding: .75rem 1.25rem;
  border-bottom: 1px solid var(--rule);
}
.brand { font-weight: 600; text-decoration: none; color: var(--fg); }

.switcher { display: flex; gap: .25rem; }
.switcher button {
  font: inherit; font-size: .85rem;
  padding: .3rem .7rem;
  border: 1px solid var(--rule);
  background: transparent; color: var(--muted);
  border-radius: 999px; cursor: pointer;
}
.switcher button:hover { border-color: var(--accent); color: var(--accent); }
.switcher button[aria-pressed="true"] {
  background: var(--accent-soft); border-color: var(--accent); color: var(--accent);
  font-weight: 600;
}
.switcher.big button { font-size: 1rem; padding: .5rem 1.1rem; }

/* ---------------------------------------------------------------- layout */

.layout { display: flex; align-items: flex-start; gap: 2rem; }

.sidebar {
  flex: 0 0 16rem;
  padding: 1.5rem 0 3rem 1.25rem;
  position: sticky; top: 0; max-height: 100vh; overflow-y: auto;
  font-size: .9rem;
}
.sidebar h2.tier {
  font-size: .72rem; text-transform: uppercase; letter-spacing: .09em;
  color: var(--muted); margin: 1.4rem 0 .4rem;
}
.sidebar ul { list-style: none; margin: 0; padding: 0; }
.sidebar li { margin: .15rem 0; }
.sidebar li a {
  display: block; padding: .25rem .5rem; border-radius: 4px;
  text-decoration: none; color: var(--fg);
}
.sidebar li a:hover { background: var(--accent-soft); }
.sidebar li.current > a {
  background: var(--accent-soft); color: var(--accent); font-weight: 600;
}

main {
  flex: 1 1 auto; min-width: 0;
  max-width: var(--measure);
  padding: 1.5rem 1.25rem 4rem;
}
/* The landing and status pages now sit inside the same flex .layout as a
   lesson, so they must not also center themselves with auto margins. They
   get a wider measure because tier cards and a status table are wider than
   prose. */
.landing main, .statuspage main { max-width: 62rem; }

h1 { font-size: 1.9rem; line-height: 1.25; margin: .2rem 0 1rem; }
h2 { font-size: 1.35rem; margin: 2.2rem 0 .6rem; }
h3 { font-size: 1.1rem; margin: 1.6rem 0 .4rem; }

/* ------------------------------------------------------------------ code */

code, pre, kbd {
  font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  font-size: .875em;
}
code { background: var(--code-bg); padding: .12em .35em; border-radius: 3px; }
pre {
  background: var(--code-bg);
  padding: .9rem 1rem;
  border-radius: 6px;
  border: 1px solid var(--rule);
  overflow-x: auto;
}
pre code { background: none; padding: 0; }

blockquote {
  margin: 1.2rem 0; padding: .1rem 1rem;
  border-left: 3px solid var(--rule); color: var(--muted);
}

table { border-collapse: collapse; width: 100%; margin: 1.2rem 0; font-size: .93rem; }
th, td { text-align: left; padding: .45rem .6rem; border-bottom: 1px solid var(--rule); }
th { font-weight: 600; }

/* Wide content scrolls inside its own box; the page never scrolls sideways. */
.tablewrap { overflow-x: auto; }

/* ------------------------------------------------------------------- toc */

.toc {
  border: 1px solid var(--rule); border-radius: 6px;
  padding: .5rem .9rem; margin: 0 0 1.8rem; font-size: .9rem;
}
.toc summary { cursor: pointer; color: var(--muted); }
.toc ul { margin: .5rem 0; padding-left: 1.1rem; }

/* -------------------------------------------------------------- prevnext */

.prevnext {
  display: flex; justify-content: space-between; gap: 1rem;
  margin-top: 3rem; padding-top: 1.2rem; border-top: 1px solid var(--rule);
}
.prevnext a {
  flex: 1 1 0; text-decoration: none;
  padding: .7rem .9rem; border: 1px solid var(--rule); border-radius: 6px;
}
.prevnext a:hover { border-color: var(--accent); }
.prevnext .next { text-align: right; }
.prevnext span {
  display: block; font-size: .72rem; text-transform: uppercase;
  letter-spacing: .09em; color: var(--muted);
}

/* ---------------------------------------------------------------- badges */

.badge { display: inline-block; padding: .25rem .7rem; border-radius: 999px; font-size: .82rem; }
.badge.green { background: var(--green-bg); color: var(--green); }
.badge.red { background: var(--red-bg); color: var(--red); }
.badge.manual { background: var(--amber-bg); color: var(--amber); }
.badge.unverified { background: var(--code-bg); color: var(--muted); }

/* --------------------------------------------------------------- landing */

.hero { margin: 2rem 0 1rem; }
.hero h1 { font-size: 2.4rem; }

.chooser { margin: 2rem 0 2.5rem; padding: 1.2rem; background: var(--code-bg); border-radius: 8px; }
.chooser h2 { margin-top: 0; }

.tier-card { margin: 2rem 0; padding-top: 1.5rem; border-top: 1px solid var(--rule); }
.tier-card .blurb { font-size: 1.05rem; }
.tier-card .meta { color: var(--muted); font-size: .9rem; }
.lesson-list { list-style: none; padding: 0; }
.lesson-list li {
  display: flex; align-items: baseline; gap: .6rem;
  padding: .35rem 0; border-bottom: 1px dotted var(--rule);
}
.tag {
  font-size: .7rem; text-transform: uppercase; letter-spacing: .06em;
  color: var(--muted); border: 1px solid var(--rule);
  border-radius: 3px; padding: 0 .3rem;
}

.verifystrip {
  margin: 2.5rem 0 0; padding: .9rem 1.1rem;
  background: var(--accent-soft); border-radius: 6px; font-size: .92rem;
}

/* ---------------------------------------------------------------- status */

.statustable td.state { font-weight: 600; }
.statustable tr.green td.state { color: var(--green); }
.statustable tr.red td.state { color: var(--red); }
.statustable tr.manual td.state { color: var(--amber); }
.statustable tr.unverified td.state { color: var(--muted); }

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

.sitefoot {
  border-top: 1px solid var(--rule);
  padding: 1.5rem 1.25rem 3rem;
  font-size: .9rem; color: var(--muted);
}
.sitefoot a { color: var(--accent); }
.muted { color: var(--muted); }

/* ---------------------------------------------------------------- mobile */

@media (max-width: 48rem) {
  .layout { display: block; }
  .sidebar {
    position: static; max-height: none; width: auto;
    padding: 1rem 1.25rem; border-bottom: 1px solid var(--rule);
  }
  .prevnext { flex-direction: column; }
  .prevnext .next { text-align: left; }
}

.lesson-list li.pending { color: var(--muted); font-style: italic; border-bottom: none; }