/* Aer: Semnal — Teo's console. Story in serif, data and controls in mono. */
:root {
  --bg: #0c0e0d;
  --panel: #131715;
  --line: #24302b;
  --ink: #d9d4c7;
  --muted: #8a8f86;
  --amber: #e3a948;
  --amber-dim: #e3a94826;
  --ok: #7fbf8e;
  --err: #e0705c;
  --mono: ui-monospace, "JetBrains Mono", "IBM Plex Mono", Menlo, Consolas, monospace;
  --serif: "Iowan Old Style", "Palatino Linotype", Palatino, Georgia, serif;
}
* { box-sizing: border-box; }
html { background: var(--bg); color: var(--ink); }
body { margin: 0; font: 17px/1.65 var(--serif); min-height: 100vh; display: flex; flex-direction: column; }
a { color: var(--amber); text-underline-offset: 3px; }
main { flex: 1; width: 100%; max-width: 1080px; margin: 0 auto; padding: 32px 20px 64px; }

.bar { display: flex; justify-content: space-between; align-items: center; gap: 16px; flex-wrap: wrap;
  padding: 14px 20px; border-bottom: 1px solid var(--line); font: 13px var(--mono); letter-spacing: .04em; }
.brand { color: var(--ink); text-decoration: none; font-weight: 700; letter-spacing: .3em; }
.brand span { color: var(--amber); }
.bar nav { display: flex; align-items: center; gap: 18px; }
.bar form { margin: 0; }
.who { color: var(--muted); }
button.link { background: none; border: 0; padding: 0; color: var(--amber); font: inherit; cursor: pointer; text-decoration: underline; text-underline-offset: 3px; }

footer { display: flex; justify-content: center; gap: 8px; padding: 14px; border-top: 1px solid var(--line);
  font: 12px var(--mono); color: var(--muted); letter-spacing: .12em; text-transform: uppercase; }
.blink { color: var(--amber); animation: blink 1.2s steps(2) infinite; }
@keyframes blink { 50% { opacity: 0; } }
@media (prefers-reduced-motion: reduce) { .blink { animation: none; } }

h1 { font: 600 30px/1.25 var(--serif); margin: 0 0 24px; }
h2 { font: 600 13px var(--mono); letter-spacing: .14em; text-transform: uppercase; color: var(--amber); margin: 40px 0 14px; }
h3 { font: 600 13px var(--mono); letter-spacing: .14em; text-transform: uppercase; color: var(--muted); margin: 28px 0 10px; }

.intro { max-width: 640px; margin: 10vh auto 0; }
.intro h1 { font-size: clamp(30px, 5vw, 46px); }
.eyebrow { font: 12px var(--mono); letter-spacing: .2em; text-transform: uppercase; color: var(--amber); }
.lede { font-size: 19px; color: var(--ink); }
.actions { margin-top: 28px; display: flex; gap: 12px; flex-wrap: wrap; }

.btn { display: inline-block; font: 600 14px var(--mono); letter-spacing: .06em; padding: 11px 18px;
  background: var(--amber); color: #15120a; border: 1px solid var(--amber); border-radius: 3px; text-decoration: none; cursor: pointer; }
.btn:hover { filter: brightness(1.08); }
.btn.ghost { background: transparent; color: var(--amber); }
.btn:focus-visible, input:focus-visible, a:focus-visible { outline: 2px solid var(--amber); outline-offset: 2px; }

.form { max-width: 420px; margin: 6vh auto 0; }
.form form { display: grid; gap: 16px; }
label { display: grid; gap: 6px; font: 13px var(--mono); color: var(--muted); }
input { font: 16px var(--mono); color: var(--ink); background: var(--panel); border: 1px solid var(--line); border-radius: 3px; padding: 11px 12px; width: 100%; }
.err { font: 14px var(--mono); color: var(--err); border-left: 3px solid var(--err); padding: 4px 12px; }
.ok { font: 14px var(--mono); color: var(--ink); border-left: 3px solid var(--ok); padding: 4px 12px; }
.muted { color: var(--muted); font-size: 15px; }

.cols { display: grid; grid-template-columns: 220px minmax(0, 1fr); gap: 48px; }
@media (max-width: 760px) { .cols { grid-template-columns: 1fr; gap: 24px; } }
aside { position: sticky; top: 20px; align-self: start; }
@media (max-width: 760px) { aside { position: static; } }
.chapters { list-style: none; margin: 0; padding: 0; font: 13px/1.4 var(--mono); }
.chapters li { padding: 7px 0 7px 14px; border-left: 2px solid var(--line); }
.chapters a { color: var(--ink); text-decoration: none; }
.chapters a:hover { color: var(--amber); }
.chapters .open { border-color: var(--amber); }
.chapters .solved { border-color: var(--ok); }
.chapters .solved a::after { content: " ✓"; color: var(--ok); }
.chapters .locked { color: #4a524d; }

.story { max-width: 640px; }
.story p { margin: 0 0 1em; }
.epilog { border-left: 2px solid var(--amber); padding-left: 18px; }

.statement, .console { font: 15px/1.6 var(--mono); }
.statement { max-width: 760px; }
.statement p { margin: 0 0 1em; }
.statement ul, .statement ol { padding-left: 22px; }
.statement li { margin: 4px 0; }
code { font-family: var(--mono); font-size: .92em; background: var(--panel); border: 1px solid var(--line); border-radius: 3px; padding: 1px 5px; }
pre { background: var(--panel); border: 1px solid var(--line); border-radius: 3px; padding: 14px 16px; overflow-x: auto; font: 13px/1.5 var(--mono); }
pre code { background: none; border: 0; padding: 0; font-size: inherit; }
table { border-collapse: collapse; font: 13px var(--mono); margin: 0 0 1em; display: block; overflow-x: auto; }
th, td { border-bottom: 1px solid var(--line); padding: 7px 14px 7px 0; text-align: left; vertical-align: top; }
th { color: var(--muted); font-weight: 400; }

.console { margin-top: 36px; padding: 22px; background: var(--panel); border: 1px solid var(--line); border-radius: 4px; }
.answer { display: flex; gap: 10px; align-items: center; flex-wrap: wrap; margin-top: 14px; }
.answer label { flex-basis: 100%; }
.answer input { flex: 1 1 260px; width: auto; }

.reveal { margin-top: 36px; padding: 22px 24px; border: 1px solid var(--amber); background: var(--amber-dim); border-radius: 4px; max-width: 680px; }
.reveal p:last-child { margin-bottom: 0; }

.entry { padding-bottom: 32px; border-bottom: 1px solid var(--line); margin-bottom: 32px; }
.entry h2 { margin-top: 0; }

p { margin: 0 0 1em; }
.reveal > :first-child, .story > :first-child, .statement > h2:first-child { margin-top: 0; }
@media (max-width: 760px) {
  .cols > section { order: 1; }
  .cols > aside { order: 2; border-top: 1px solid var(--line); padding-top: 20px; }
}