/* AI Engineering Lab, program site.
   Same design tokens as the diagrams in assets/diagrams, so a figure reads as
   part of the page instead of a pasted screenshot. */

:root {
  --bg: #FBFAF8;
  --bg-2: #F3F1EC;
  --panel: #FFFFFF;
  --panel-2: #F8F7F4;
  --ink: #14161A;
  --ink-2: #3D444F;
  --mut: #5A6270;
  --faint: #8A9099;
  --line: #DFDCD5;
  --line-2: #EDEAE4;
  --navy: #0A0F1C;
  --navy-2: #16203A;
  --orange: #F14B21;
  --orange-lit: #FF6A2C;
  --teal: #0E9384;
  --indigo: #4260E8;
  --violet: #7C4DE0;
  --rose: #DC3A72;
  --amber: #E8940C;
  --slate: #566172;
  --shadow: 0 1px 2px rgba(20, 22, 26, .05), 0 8px 20px rgba(20, 22, 26, .05);
  --radius: 12px;
  --wrap: 940px;
}

* { margin: 0; padding: 0; box-sizing: border-box; }

html { scroll-behavior: smooth; scroll-padding-top: 76px; }

body {
  font-family: "Helvetica Neue", Helvetica, -apple-system, Arial, sans-serif;
  -webkit-font-smoothing: antialiased;
  background: var(--bg);
  color: var(--ink);
  font-size: 16px;
  line-height: 1.6;
}

.mono { font-family: Menlo, "SF Mono", ui-monospace, Consolas, monospace; }

a { color: inherit; }
img { display: block; max-width: 100%; height: auto; }

.wrap { width: 100%; max-width: var(--wrap); margin: 0 auto; padding: 0 24px; }

.skip {
  position: absolute; left: -9999px; top: 0; background: var(--navy);
  color: #fff; padding: 12px 18px; z-index: 100;
}
.skip:focus { left: 12px; top: 12px; }

/* ── sticky nav ─────────────────────────────────────────────── */
.nav {
  position: sticky; top: 0; z-index: 40;
  background: rgba(251, 250, 248, .92);
  backdrop-filter: saturate(180%) blur(12px);
  border-bottom: 1px solid var(--line);
}
.nav .wrap { display: flex; align-items: center; gap: 20px; height: 56px; }
.nav .mark {
  font-size: 11.5px; font-weight: 800; letter-spacing: .18em;
  text-transform: uppercase; text-decoration: none; white-space: nowrap;
}
.nav .mark span { color: var(--orange); }
.nav ul { list-style: none; display: flex; gap: 20px; margin-left: auto; }
.nav a.l {
  font-size: 12.5px; letter-spacing: .04em; color: var(--mut);
  text-decoration: none; padding: 4px 0; border-bottom: 1px solid transparent;
}
.nav a.l:hover, .nav a.l:focus-visible { color: var(--ink); border-bottom-color: var(--orange); }
.nav .gh {
  font-size: 12px; font-weight: 700; letter-spacing: .05em; text-decoration: none;
  border: 1px solid var(--line); border-radius: 7px; padding: 7px 12px; color: var(--ink);
}
.nav .gh:hover { border-color: var(--ink); }

/* ── hero ───────────────────────────────────────────────────── */
.hero {
  position: relative; overflow: hidden;
  background: var(--navy);
  color: #F2F6FC;
  border-bottom: 1px solid var(--navy-2);
}
.hero .tex {
  position: absolute; inset: 0;
  background: url("hero-texture.jpg") center / cover no-repeat;
  opacity: .55;
}
.hero .scrim {
  position: absolute; inset: 0;
  background:
    linear-gradient(100deg, rgba(10, 15, 28, .96) 0%, rgba(10, 15, 28, .82) 46%, rgba(10, 15, 28, .34) 100%);
}
.hero .wrap { position: relative; padding: 74px 24px 62px; }
.hero .eyebrow {
  font-size: 10.5px; letter-spacing: .2em; text-transform: uppercase;
  color: #8FA0BA; display: block; margin-bottom: 20px;
}
.hero h1 {
  font-size: clamp(34px, 6vw, 52px); font-weight: 800; letter-spacing: -.024em;
  line-height: 1.06; max-width: 20ch;
}
.hero h1 em { font-style: normal; color: var(--orange-lit); }
.hero .lede {
  margin-top: 18px; font-size: 17px; line-height: 1.62; color: #C9D5E8; max-width: 58ch;
}
.hero .cta { display: flex; flex-wrap: wrap; gap: 12px; margin-top: 30px; }
.btn {
  display: inline-flex; align-items: center; gap: 9px; text-decoration: none;
  font-size: 14px; font-weight: 700; letter-spacing: .01em;
  padding: 13px 20px; border-radius: 9px; border: 1px solid transparent;
}
.btn.p { background: var(--orange); color: #fff; }
.btn.p:hover { background: #D93F17; }
.btn.s { border-color: #2A3A5C; color: #E7EDF7; }
.btn.s:hover { border-color: #6D82A8; background: rgba(255, 255, 255, .04); }
.hero .facts { display: flex; flex-wrap: wrap; gap: 34px; margin-top: 40px; }
.hero .facts div { min-width: 132px; }
.hero .facts .n {
  font-size: 25px; font-weight: 800; letter-spacing: -.02em; line-height: 1;
  color: #F2F6FC;
}
.hero .facts .l {
  display: block; margin-top: 7px; font-size: 11px; letter-spacing: .13em;
  text-transform: uppercase; color: #8FA0BA;
}

/* ── sections ───────────────────────────────────────────────── */
section { padding: 66px 0; border-bottom: 1px solid var(--line); }
section:nth-of-type(even) { background: var(--bg-2); }
.k {
  font-size: 10px; letter-spacing: .19em; text-transform: uppercase;
  color: var(--mut); font-weight: 700; display: flex; align-items: center; gap: 9px;
  margin-bottom: 14px;
}
.k::before { content: ""; width: 15px; height: 2px; background: var(--orange); border-radius: 1px; }
h2 {
  font-size: clamp(25px, 3.4vw, 33px); font-weight: 800; letter-spacing: -.021em;
  line-height: 1.14; max-width: 26ch;
}
h2 em { font-style: normal; color: var(--orange); }
.sub { margin-top: 13px; font-size: 16px; line-height: 1.62; color: var(--mut); max-width: 74ch; }
.sub + .sub { margin-top: 11px; }
.sub a { color: var(--ink); text-decoration-color: var(--orange); text-underline-offset: 3px; }

figure { margin: 32px 0 0; }
figure img { border: 1px solid var(--line); border-radius: var(--radius); background: var(--panel); }
figcaption { margin-top: 11px; font-size: 12.5px; line-height: 1.5; color: var(--faint); }

/* ── week list ──────────────────────────────────────────────── */
.filters { display: flex; flex-wrap: wrap; gap: 8px; margin: 26px 0 4px; }
.chip {
  font-family: Menlo, "SF Mono", ui-monospace, monospace;
  font-size: 10.5px; letter-spacing: .1em; text-transform: uppercase; font-weight: 700;
  padding: 8px 12px; border-radius: 7px; cursor: pointer;
  border: 1px solid var(--line); background: var(--panel); color: var(--mut);
}
.chip:hover { border-color: var(--faint); color: var(--ink); }
.chip[aria-pressed="true"] { background: var(--navy); border-color: var(--navy); color: #fff; }
.chip .d {
  display: inline-block; width: 7px; height: 7px; border-radius: 50%;
  margin-right: 7px; vertical-align: 1px; background: var(--c, var(--slate));
}

.phase { margin-top: 34px; }
.phase > h3 {
  font-size: 15px; font-weight: 800; letter-spacing: -.005em;
  display: flex; align-items: baseline; gap: 10px; flex-wrap: wrap;
  padding-bottom: 11px; border-bottom: 1px solid var(--line);
}
.phase > h3 .n {
  font-family: Menlo, "SF Mono", ui-monospace, monospace;
  font-size: 10px; letter-spacing: .13em; text-transform: uppercase;
  color: #fff; background: var(--c, var(--slate)); padding: 4px 8px; border-radius: 5px;
}
.phase > h3 .w { font-size: 11.5px; font-weight: 600; color: var(--faint); margin-left: auto; }
.phase > p { font-size: 13.5px; line-height: 1.55; color: var(--mut); margin-top: 11px; max-width: 78ch; }

.weeks { list-style: none; display: grid; grid-template-columns: repeat(2, 1fr); gap: 14px; margin-top: 18px; }
.weeks li { display: flex; }
.weeks a {
  display: flex; gap: 14px; text-decoration: none; width: 100%;
  background: var(--panel); border: 1px solid var(--line);
  border-radius: 10px; padding: 15px 16px;
  transition: box-shadow .14s ease, border-color .14s ease;
}
.weeks a:hover, .weeks a:focus-visible { border-color: var(--faint); box-shadow: var(--shadow); }
.weeks .wn {
  font-family: Menlo, "SF Mono", ui-monospace, monospace;
  font-size: 11px; font-weight: 700; letter-spacing: .06em; color: var(--c, var(--slate));
  padding-top: 2px; white-space: nowrap;
}
.weeks .wt { font-size: 14px; font-weight: 750; line-height: 1.3; color: var(--ink); }
.weeks .wo {
  font-size: 12.5px; line-height: 1.5; color: var(--mut); margin-top: 5px;
  display: -webkit-box; -webkit-line-clamp: 3; -webkit-box-orient: vertical; overflow: hidden;
}
.weeks .wu {
  font-size: 11px; letter-spacing: .04em; color: var(--faint); margin-top: 8px;
  display: block; text-transform: uppercase;
}

/* ── steps, table, faq, callout ─────────────────────────────── */
.steps { list-style: none; counter-reset: s; margin-top: 26px; display: grid; gap: 12px; }
.steps li {
  counter-increment: s; position: relative; padding: 16px 18px 16px 56px;
  background: var(--panel); border: 1px solid var(--line); border-radius: 10px;
}
.steps li::before {
  content: counter(s); position: absolute; left: 18px; top: 15px;
  width: 24px; height: 24px; border-radius: 50%; background: var(--navy); color: #fff;
  font-size: 12px; font-weight: 800; display: grid; place-items: center;
}
.steps h4 { font-size: 14.5px; font-weight: 750; }
.steps p { font-size: 13.5px; line-height: 1.55; color: var(--mut); margin-top: 4px; }
.steps code, .inline-code {
  font-family: Menlo, "SF Mono", ui-monospace, monospace; font-size: 12.5px;
  background: var(--bg-2); border: 1px solid var(--line-2); border-radius: 5px; padding: 1px 5px;
}

pre {
  margin-top: 22px; background: var(--navy); color: #DCE4F2; border-radius: var(--radius);
  padding: 20px 22px; overflow-x: auto; position: relative;
}
pre code { font-family: Menlo, "SF Mono", ui-monospace, monospace; font-size: 13px; line-height: 1.8; }
pre .c { color: #7E8CA5; }
.copy {
  position: absolute; top: 12px; right: 12px; background: rgba(255, 255, 255, .06);
  border: 1px solid #2A3A5C; color: #C9D5E8; border-radius: 6px; cursor: pointer;
  font-family: Menlo, "SF Mono", ui-monospace, monospace;
  font-size: 10px; letter-spacing: .1em; text-transform: uppercase; padding: 6px 9px;
}
.copy:hover { background: rgba(255, 255, 255, .12); color: #fff; }

table { width: 100%; border-collapse: collapse; margin-top: 26px; background: var(--panel); }
th, td { text-align: left; padding: 12px 15px; border-bottom: 1px solid var(--line-2); font-size: 13.5px; }
th {
  font-size: 10px; letter-spacing: .13em; text-transform: uppercase; font-weight: 700;
  background: var(--bg-2); color: var(--ink-2); border-bottom: 1px solid var(--line);
}
td { color: var(--mut); vertical-align: top; }
td:first-child { color: var(--ink); font-weight: 700; white-space: nowrap; }

.g2 { display: grid; grid-template-columns: repeat(2, 1fr); gap: 14px; margin-top: 26px; }
.card {
  background: var(--panel); border: 1px solid var(--line); border-radius: 10px; padding: 17px 19px;
}
.card h4 { font-size: 14px; font-weight: 750; line-height: 1.35; }
.card p { font-size: 13px; line-height: 1.6; color: var(--mut); margin-top: 7px; }
.card p code { font-size: 12px; }

.note {
  display: flex; gap: 16px; margin-top: 30px; padding: 18px 20px;
  background: #FFF6F1; border: 1px solid #F3CDBC; border-radius: 10px;
}
.note .l {
  font-family: Menlo, "SF Mono", ui-monospace, monospace;
  font-size: 10px; letter-spacing: .15em; text-transform: uppercase; font-weight: 700;
  color: var(--orange); white-space: nowrap; padding-top: 3px;
}
.note p { font-size: 13.5px; line-height: 1.58; color: var(--ink-2); }

/* ── footer ─────────────────────────────────────────────────── */
footer { background: var(--navy); color: #C9D5E8; padding: 52px 0 38px; }
footer .top { display: flex; flex-wrap: wrap; gap: 30px; justify-content: space-between; }
footer .brand { font-size: 13px; font-weight: 800; letter-spacing: .2em; color: #F2F6FC; }
footer .dom { font-size: 11px; letter-spacing: .1em; color: var(--orange-lit); font-weight: 700; margin-top: 8px; }
footer nav { display: flex; flex-wrap: wrap; gap: 8px 22px; }
footer nav a { font-size: 12.5px; color: #C9D5E8; text-decoration: none; }
footer nav a:hover { color: #fff; text-decoration: underline; text-decoration-color: var(--orange-lit); }
footer .rule { height: 1px; background: #2A3A5C; margin: 26px 0 16px; }
footer .fine { display: flex; flex-wrap: wrap; gap: 6px 20px; font-size: 11.5px; color: #8092AD; }
footer .fine a { color: #8092AD; }

/* ── responsive ─────────────────────────────────────────────── */
@media (max-width: 800px) {
  .weeks, .g2 { grid-template-columns: 1fr; }
  .nav ul { display: none; }
  .hero .wrap { padding: 56px 24px 48px; }
  section { padding: 50px 0; }
  .phase > h3 .w { margin-left: 0; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .weeks a { transition: none; }
}

:focus-visible { outline: 2px solid var(--orange); outline-offset: 2px; border-radius: 4px; }