:root {
  --bg: #f7f5f0;
  --surface: #ffffff;
  --surface-2: #efece4;
  --ink: #14232a;
  --ink-2: #44555c;
  --ink-3: #6b7a80;
  --line: #ddd8cc;
  --brand: #0f2a33;
  --teal: #1f8a7f;
  --teal-soft: #d8efec;
  --amber: #b9771a;
  --amber-soft: #f8ead2;
  --red: #b4473b;
  --red-soft: #f6e1dd;
  --code-bg: #0f2a33;
  --code-ink: #e3ecee;
  --code-dim: #8fa7ad;
  --code-accent: #f2b84b;
  --radius: 14px;
  --max: 1120px;
  color-scheme: light;
}

@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --bg: #0c1a1f;
    --surface: #12242b;
    --surface-2: #172d35;
    --ink: #e6eef0;
    --ink-2: #b2c2c7;
    --ink-3: #8299a0;
    --line: #24404a;
    --brand: #e6eef0;
    --teal: #5fc4b8;
    --teal-soft: #163a3a;
    --amber: #f2b84b;
    --amber-soft: #3a2f17;
    --red: #e88a7e;
    --red-soft: #3c2220;
    --code-bg: #081216;
    color-scheme: dark;
  }
}

:root[data-theme="dark"] {
  --bg: #0c1a1f;
  --surface: #12242b;
  --surface-2: #172d35;
  --ink: #e6eef0;
  --ink-2: #b2c2c7;
  --ink-3: #8299a0;
  --line: #24404a;
  --brand: #e6eef0;
  --teal: #5fc4b8;
  --teal-soft: #163a3a;
  --amber: #f2b84b;
  --amber-soft: #3a2f17;
  --red: #e88a7e;
  --red-soft: #3c2220;
  --code-bg: #081216;
  color-scheme: dark;
}

*, *::before, *::after { box-sizing: border-box; }

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

body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font: 17px/1.6 ui-sans-serif, system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  overflow-x: hidden;
}

a { color: var(--teal); text-decoration-thickness: 1px; text-underline-offset: 3px; }
a:hover { text-decoration-thickness: 2px; }

code, pre, .mono { font-family: ui-monospace, "SF Mono", "Cascadia Code", Consolas, Menlo, monospace; }
code { font-size: .88em; background: var(--surface-2); padding: .1em .35em; border-radius: 5px; }

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

/* Header */
.top {
  position: sticky; top: 0; z-index: 10;
  background: color-mix(in srgb, var(--bg) 88%, transparent);
  backdrop-filter: saturate(1.4) blur(10px);
  border-bottom: 1px solid var(--line);
}
.top .wrap { display: flex; align-items: center; gap: 24px; height: 64px; }
.logo { display: flex; align-items: center; gap: 10px; color: var(--ink); text-decoration: none; font-weight: 700; font-size: 19px; letter-spacing: -.01em; }
.logo svg { width: 28px; height: 28px; }
.top nav { display: flex; gap: 22px; margin-left: auto; font-size: 15px; }
.top nav a { color: var(--ink-2); text-decoration: none; }
.top nav a:hover { color: var(--ink); }

/* Hero */
.hero { padding: 88px 0 72px; position: relative; overflow: hidden; }
.hero .wrap { display: grid; grid-template-columns: 1.1fr .9fr; gap: 56px; align-items: center; }
.pill {
  display: inline-flex; align-items: center; gap: 8px;
  font-size: 13px; font-weight: 600; letter-spacing: .02em;
  padding: 5px 12px; border-radius: 999px;
  background: var(--amber-soft); color: var(--amber);
}
.pill::before { content: ""; width: 7px; height: 7px; border-radius: 50%; background: currentColor; }
h1 {
  font-size: clamp(38px, 5.4vw, 62px); line-height: 1.04; letter-spacing: -.03em;
  margin: 20px 0 20px; font-weight: 750;
}
h1 em { font-style: normal; color: var(--teal); }
.lede { font-size: 20px; color: var(--ink-2); max-width: 36em; margin: 0 0 32px; }
.ctas { display: flex; gap: 12px; flex-wrap: wrap; }
.btn {
  display: inline-flex; align-items: center; gap: 8px;
  padding: 12px 20px; border-radius: 10px; font-weight: 600; font-size: 16px;
  text-decoration: none; border: 1px solid transparent;
}
.btn.primary { background: var(--ink); color: var(--bg); }
.btn.primary:hover { opacity: .9; }
.btn.ghost { border-color: var(--line); color: var(--ink); background: var(--surface); }
.btn.ghost:hover { border-color: var(--ink-3); }

.stack-art { width: 100%; height: auto; max-width: 460px; justify-self: center; }
.stack-art .l1 { fill: var(--amber); }
.stack-art .l2 { fill: var(--teal); }
.stack-art .l3 { fill: var(--ink-3); opacity: .55; }
.stack-art .l4 { fill: var(--ink-3); opacity: .3; }
.stack-art .lbl { fill: var(--ink-2); font: 600 13px ui-sans-serif, system-ui, sans-serif; }
.stack-art .lbl-dim { fill: var(--ink-3); font: 12px ui-monospace, Consolas, monospace; }
.stack-art .tick { stroke: var(--line); stroke-width: 1; }

/* Sections */
section { padding: 88px 0; }
section.alt { background: var(--surface); border-top: 1px solid var(--line); border-bottom: 1px solid var(--line); }
.eyebrow { font-size: 13px; font-weight: 700; letter-spacing: .12em; text-transform: uppercase; color: var(--teal); margin: 0 0 12px; }
h2 { font-size: clamp(28px, 3.6vw, 40px); line-height: 1.15; letter-spacing: -.02em; margin: 0 0 16px; font-weight: 720; max-width: 22em; }
h3 { font-size: 19px; line-height: 1.3; margin: 0 0 8px; letter-spacing: -.01em; }
.sub { color: var(--ink-2); font-size: 18px; max-width: 42em; margin: 0 0 48px; }

/* Problem */
.problems { display: grid; grid-template-columns: repeat(3, 1fr); gap: 20px; }
.problem { border-top: 3px solid var(--red); padding-top: 18px; }
.problem p { color: var(--ink-2); margin: 0; }

/* Layers */
.split { display: grid; grid-template-columns: 1fr 1fr; gap: 48px; align-items: start; }
.cascade { display: flex; flex-direction: column; gap: 10px; }
.tier {
  display: flex; align-items: center; justify-content: space-between; gap: 12px;
  background: var(--surface); border: 1px solid var(--line); border-radius: 12px;
  padding: 14px 18px;
}
section.alt .tier { background: var(--bg); }
.tier:nth-child(2) { margin-left: 22px; }
.tier:nth-child(3) { margin-left: 44px; }
.tier:nth-child(4) { margin-left: 66px; border-color: var(--teal); }
.tier b { font-size: 15px; }
.tier span { color: var(--ink-3); font-size: 14px; }
.modes { display: grid; gap: 14px; margin-top: 28px; }
.mode { display: grid; grid-template-columns: 92px 1fr; gap: 14px; align-items: baseline; }
.tag {
  display: inline-block; text-align: center; font: 600 12px ui-monospace, Consolas, monospace;
  padding: 4px 8px; border-radius: 6px; letter-spacing: .02em;
}
.tag.locked { background: var(--red-soft); color: var(--red); }
.tag.override { background: var(--amber-soft); color: var(--amber); }
.tag.append { background: var(--teal-soft); color: var(--teal); }
.mode p { margin: 0; color: var(--ink-2); }

/* Terminal */
.term {
  background: var(--code-bg); color: var(--code-ink); border-radius: var(--radius);
  padding: 0; overflow: hidden; font-size: 14px; line-height: 1.7;
  box-shadow: 0 20px 50px -24px rgba(8, 20, 24, .45);
}
.term .bar { display: flex; gap: 7px; padding: 12px 16px; border-bottom: 1px solid rgba(255,255,255,.08); }
.term .bar i { width: 11px; height: 11px; border-radius: 50%; background: rgba(255,255,255,.18); }
.term pre { margin: 0; padding: 18px 20px; overflow-x: auto; white-space: pre; }
.term .c { color: var(--code-dim); }
.term .p { color: var(--code-accent); user-select: none; }
.term .o { color: #9fd9cf; }

/* Cards */
.cards { display: grid; grid-template-columns: repeat(3, 1fr); gap: 18px; }
.card {
  background: var(--surface); border: 1px solid var(--line); border-radius: var(--radius);
  padding: 26px 24px;
}
section.alt .card { background: var(--bg); }
.card .ic { width: 38px; height: 38px; border-radius: 10px; display: grid; place-items: center; background: var(--teal-soft); color: var(--teal); margin-bottom: 16px; }
.card .ic svg { width: 20px; height: 20px; }
.card p { margin: 0; color: var(--ink-2); font-size: 16px; }

/* Break-glass */
.steps { list-style: none; padding: 0; margin: 0; counter-reset: s; display: grid; gap: 18px; }
.steps li { counter-increment: s; display: grid; grid-template-columns: 36px 1fr; gap: 14px; }
.steps li::before {
  content: counter(s); width: 32px; height: 32px; border-radius: 50%;
  display: grid; place-items: center; font-weight: 700; font-size: 14px;
  background: var(--amber-soft); color: var(--amber);
}
.steps b { display: block; margin-bottom: 2px; }
.steps span { color: var(--ink-2); font-size: 16px; }

/* Architecture */
.arch { background: var(--surface); border: 1px solid var(--line); border-radius: var(--radius); padding: 24px; }
.arch svg { width: 100%; height: auto; display: block; }
.arch .box { fill: var(--bg); stroke: var(--line); stroke-width: 1.5; }
.arch .box.key { stroke: var(--teal); }
.arch .box.lock { stroke: var(--amber); }
.arch .t { fill: var(--ink); font: 600 14px ui-sans-serif, system-ui, sans-serif; }
.arch .s { fill: var(--ink-3); font: 12px ui-sans-serif, system-ui, sans-serif; }
.arch .ln { stroke: var(--ink-3); stroke-width: 1.5; fill: none; }
.arch .ah { fill: var(--ink-3); }
.arch-notes { display: grid; grid-template-columns: repeat(3, 1fr); gap: 20px; margin-top: 28px; }
.arch-notes p { margin: 0; color: var(--ink-2); font-size: 16px; }

/* Tables */
.tbl { width: 100%; border-collapse: collapse; font-size: 16px; }
.tbl th, .tbl td { text-align: left; padding: 12px 14px; border-bottom: 1px solid var(--line); vertical-align: top; }
.tbl th { font-size: 13px; text-transform: uppercase; letter-spacing: .08em; color: var(--ink-3); font-weight: 700; }
.tbl td:last-child { color: var(--ink-2); }
.tbl tr.total td { font-weight: 700; color: var(--ink); border-bottom: 0; }
.tbl-wrap { overflow-x: auto; background: var(--surface); border: 1px solid var(--line); border-radius: var(--radius); }
section.alt .tbl-wrap { background: var(--bg); }
.note { color: var(--ink-3); font-size: 14px; margin-top: 14px; }

.cost { display: grid; grid-template-columns: .8fr 1.2fr; gap: 48px; align-items: center; }
.big { font-size: clamp(56px, 8vw, 92px); font-weight: 760; letter-spacing: -.04em; line-height: 1; color: var(--teal); }
.big small { font-size: 20px; color: var(--ink-2); letter-spacing: 0; font-weight: 600; display: block; margin-top: 10px; }

/* Status */
.status { display: grid; grid-template-columns: repeat(3, 1fr); gap: 18px; }
.col { background: var(--surface); border: 1px solid var(--line); border-radius: var(--radius); padding: 22px; }
section.alt .col { background: var(--bg); }
.col h3 { display: flex; align-items: center; gap: 10px; }
.col h3::before { content: ""; width: 10px; height: 10px; border-radius: 50%; }
.col.done h3::before { background: var(--teal); }
.col.part h3::before { background: var(--amber); }
.col.next h3::before { background: var(--ink-3); }
.col ul { margin: 12px 0 0; padding-left: 18px; color: var(--ink-2); font-size: 15.5px; }
.col li { margin: 6px 0; }

/* Footer */
footer { padding: 48px 0 56px; border-top: 1px solid var(--line); color: var(--ink-3); font-size: 14px; }
footer .wrap { display: flex; gap: 24px; justify-content: space-between; flex-wrap: wrap; }
footer p { margin: 0; max-width: 40em; }
footer a { color: var(--ink-2); }

/* 404 */
.lost { min-height: 70vh; display: grid; place-items: center; text-align: center; padding: 64px 0; }
.lost h1 { margin-top: 0; }

/* Responsive */
@media (max-width: 960px) {
  .hero .wrap, .split, .cost { grid-template-columns: 1fr; gap: 40px; }
  .cards, .status, .arch-notes, .problems { grid-template-columns: 1fr 1fr; }
  .stack-art { max-width: 380px; }
}
@media (max-width: 680px) {
  body { font-size: 16px; }
  .wrap { padding: 0 16px; }
  .top nav { display: none; }
  .hero { padding: 56px 0 48px; }
  .lede { font-size: 18px; }
  section { padding: 64px 0; }
  .cards, .status, .arch-notes, .problems { grid-template-columns: 1fr; }
  .tier:nth-child(2) { margin-left: 12px; }
  .tier:nth-child(3) { margin-left: 24px; }
  .tier:nth-child(4) { margin-left: 36px; }
  .tier span { display: none; }
  .arch { padding: 12px; overflow-x: auto; }
  .arch svg { min-width: 680px; }
  .term { font-size: 12.5px; }
  .tbl th, .tbl td { padding: 10px; }
}