/* ==========================================================================
   LinuxPath landing
   Direction: the page reads like the course itself. A calm technical manual
   on a graphite-and-paper neutral, one amber accent (the product's own,
   from linuxpath/platform/design-system/MASTER.md), Onest for text and
   IBM Plex Mono only where something is typed into a shell.
   Shapes: buttons and inputs 6px, panels 10px, step tags 6px. Nothing pill.
   ========================================================================== */

:root {
  color-scheme: light;
  --bg: #f6f7f7;
  --surface: #ffffff;
  --sunken: #eceeee;
  --ink: #14181b;
  --ink-2: #3a4247;
  --muted: #5b646a;
  --line: #d9dddf;
  --line-2: #c4c9cc;
  --accent: #945605;
  --accent-hover: #7f4a04;
  --accent-ink: #ffffff;
  --success: #15803d;
  --danger: #c62828;
  --seg-1: #cdd2d5;
  --seg-1-ink: #14181b;
  --seg-2: #5b646a;
  --seg-2-ink: #ffffff;
  --seg-3: #2a3135;
  --seg-3-ink: #ffffff;
  --seg-4: #3d5566;
  --seg-4-ink: #ffffff;
  --term-bg: #0b0b0c;
  --term-fg: #d6d6d6;
  --term-dim: #a3a3a3;
  --term-ps: #e3a641;
  --shadow: 0 1px 2px rgba(20, 24, 27, 0.05), 0 18px 40px -24px rgba(20, 24, 27, 0.28);

  --font: "Onest", system-ui, -apple-system, "Segoe UI", sans-serif;
  --mono: "IBM Plex Mono", ui-monospace, "SF Mono", Menlo, monospace;
  --ease: cubic-bezier(0.22, 1, 0.36, 1);
  --maxw: 1180px;
  --gutter: 24px;
}

:root[data-theme="dark"] {
  color-scheme: dark;
  --bg: #101315;
  --surface: #171b1e;
  --sunken: #0b0d0f;
  --ink: #e7e9ea;
  --ink-2: #b3bbc0;
  --muted: #8e979c;
  --line: #262d31;
  --line-2: #3a4247;
  --accent: #f0b03c;
  --accent-hover: #f6c463;
  --accent-ink: #14181b;
  --success: #3fb96a;
  --danger: #f06a6a;
  --seg-1: #2c3337;
  --seg-1-ink: #e7e9ea;
  --seg-2: #4f595f;
  --seg-2-ink: #ffffff;
  --seg-3: #78838a;
  --seg-3-ink: #ffffff;
  --seg-4: #6f8fa3;
  --seg-4-ink: #ffffff;
  --shadow: 0 1px 2px rgba(0, 0, 0, 0.4), 0 18px 40px -24px rgba(0, 0, 0, 0.7);
}

*, *::before, *::after { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; scroll-padding-top: 80px; }
body {
  margin: 0;
  background: var(--bg);
  color: var(--ink-2);
  font: 400 16px/1.6 var(--font);
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
  overflow-x: hidden;
}
h1, h2, h3 { margin: 0; color: var(--ink); font-weight: 600; text-wrap: balance; }
p { margin: 0; }
a { color: inherit; }
ul, ol { margin: 0; padding: 0; }
svg { display: block; }
[hidden] { display: none !important; }
::selection { background: rgba(148, 86, 5, 0.18); }

code {
  font-family: var(--mono);
  font-size: 0.88em;
  padding: 0.08em 0.36em;
  border: 1px solid var(--line);
  border-radius: 4px;
  background: var(--sunken);
  color: var(--ink);
  white-space: nowrap;
}
.section--sunken code { background: var(--surface); }

.wrap { width: 100%; max-width: var(--maxw); margin-inline: auto; padding-inline: var(--gutter); }
.wrap-narrow { max-width: 820px; }

.skip-link {
  position: absolute; left: 16px; top: -48px; z-index: 30;
  padding: 8px 14px; border-radius: 6px;
  background: var(--ink); color: var(--bg); text-decoration: none;
}
.skip-link:focus { top: 12px; }

:focus-visible { outline: 2px solid var(--accent); outline-offset: 2px; }

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

.site-header {
  position: sticky; top: 0; z-index: 20;
  background: color-mix(in srgb, var(--bg) 86%, transparent);
  -webkit-backdrop-filter: saturate(140%) blur(10px);
  backdrop-filter: saturate(140%) blur(10px);
  border-bottom: 1px solid var(--line);
}
.header-inner { display: flex; align-items: center; gap: 32px; height: 64px; }
.wordmark { font-weight: 700; font-size: 18px; letter-spacing: -0.02em; color: var(--ink); text-decoration: none; }
.wordmark span { color: var(--accent); }
.wordmark--sm { font-size: 16px; }
.site-nav { display: flex; gap: 4px; margin-right: auto; }
.nav-link {
  padding: 6px 10px; border-radius: 6px;
  font-size: 15px; color: var(--ink-2); text-decoration: none;
  transition: color 0.15s, background-color 0.15s;
}
.nav-link:hover { color: var(--ink); background: var(--sunken); }
.header-tools { display: flex; align-items: center; gap: 8px; }
.icon-btn, .lang-switch {
  display: inline-grid; place-items: center;
  min-width: 36px; height: 36px; padding: 0 8px;
  border: 1px solid var(--line); border-radius: 6px;
  background: transparent; color: var(--ink-2);
  font: 500 13px var(--mono); text-decoration: none; cursor: pointer;
  transition: color 0.15s, border-color 0.15s;
}
.icon-btn:hover, .lang-switch:hover { color: var(--ink); border-color: var(--line-2); }
.theme-icon--sun { display: none; }
[data-theme="dark"] .theme-icon--sun { display: block; }
[data-theme="dark"] .theme-icon--moon { display: none; }

/* ---------------------------------------------------------------- buttons */

.btn {
  display: inline-flex; align-items: center; justify-content: center; gap: 8px;
  height: 44px; padding: 0 18px;
  border: 1px solid transparent; border-radius: 6px;
  font: 600 15px/1 var(--font); white-space: nowrap;
  text-decoration: none; cursor: pointer;
  transition: background-color 0.15s, border-color 0.15s, color 0.15s, transform 0.1s;
}
.btn:active { transform: translateY(1px); }
.btn-sm { height: 36px; padding: 0 14px; font-size: 14px; }
.btn-primary { background: var(--accent); color: var(--accent-ink); }
.btn-primary:hover { background: var(--accent-hover); }
.btn-quiet { background: transparent; color: var(--ink); border-color: var(--line-2); }
.btn-quiet:hover { border-color: var(--muted); }
.btn:disabled, .btn.is-disabled { opacity: 0.5; cursor: not-allowed; transform: none; }
.btn-quiet.is-disabled:hover { border-color: var(--line-2); }
.soon { font: 400 12px var(--mono); color: var(--muted); }

.link-btn {
  padding: 4px 0; border: 0; background: none; cursor: pointer;
  font: 500 14px var(--font); color: var(--accent);
  text-decoration: underline; text-underline-offset: 3px;
}

/* ---------------------------------------------------------------- forms */

.notify-form { display: grid; gap: 12px; }
.field-row { display: grid; grid-template-columns: 1fr 1fr; gap: 12px; }
.field { display: grid; gap: 6px; min-width: 0; }
.field-label { font-size: 14px; font-weight: 500; color: var(--ink-2); }
.field-input {
  width: 100%; height: 44px; padding: 0 12px;
  border: 1px solid var(--line-2); border-radius: 6px;
  background: var(--surface); color: var(--ink);
  font: 400 16px var(--font);
  transition: border-color 0.15s, box-shadow 0.15s;
}
.field-input::placeholder { color: var(--muted); }
.field-input:focus { outline: none; border-color: var(--accent); box-shadow: 0 0 0 3px color-mix(in srgb, var(--accent) 22%, transparent); }
.field-input.is-invalid { border-color: var(--danger); }
.field-error { font-size: 14px; color: var(--danger); }
.field-error:empty { display: none; }
.form-actions { display: flex; flex-wrap: wrap; align-items: center; gap: 12px; }
.hp-field { position: absolute; left: -9999px; width: 1px; height: 1px; opacity: 0; }
.notify-success { display: flex; gap: 10px; align-items: flex-start; color: var(--ink); }
.notify-success svg { color: var(--success); flex: none; margin-top: 3px; }
.notify-success span { font-weight: 600; }

/* ---------------------------------------------------------------- hero */

.hero { padding: 56px 0 72px; }
.hero-grid { display: grid; grid-template-columns: minmax(0, 1fr) minmax(0, 1.22fr); gap: 56px; align-items: center; }
.hero-grid > * { min-width: 0; }
.hero-title {
  font-size: clamp(2.3rem, 1.3rem + 2.6vw, 3.4rem);
  line-height: 1.05; letter-spacing: -0.035em; font-weight: 700;
}
.hero-sub { margin: 20px 0 32px; max-width: 44ch; font-size: 18px; line-height: 1.55; color: var(--ink-2); }

/* Step 01 as it looks in the course: task, terminal, Check, the check list. */
.step-demo {
  margin: 0;
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: 10px;
  box-shadow: var(--shadow);
  overflow: hidden;
}
.demo-head {
  display: flex; justify-content: space-between; align-items: baseline; gap: 16px;
  padding: 12px 18px; border-bottom: 1px solid var(--line);
}
.demo-step { font-weight: 600; font-size: 15px; color: var(--ink); }
.demo-block { font: 400 12px var(--mono); color: var(--accent); white-space: nowrap; }
.demo-body { padding: 16px 18px 18px; }
.demo-task { font-size: 15px; color: var(--ink-2); }
.term {
  margin: 12px 0 14px; padding: 14px 16px;
  background: var(--term-bg); color: var(--term-fg);
  border-radius: 8px; border: 1px solid #1d1d20;
  font: 400 13px/1.65 var(--mono);
  overflow-x: auto; white-space: pre;
}
.term .ps { color: var(--term-ps); }
.term .out { color: var(--term-dim); }
.term .cursor { display: inline-block; width: 0.6em; height: 1.1em; vertical-align: -0.2em; background: var(--term-fg); }
.demo-actions { display: flex; gap: 8px; }
.demo-checks { margin-top: 16px; padding-top: 14px; border-top: 1px solid var(--line); }
.demo-checks-h { font: 500 12px var(--mono); text-transform: uppercase; letter-spacing: 0.04em; color: var(--muted); margin-bottom: 8px; }
.demo-checks ul { list-style: none; display: grid; gap: 4px; font-size: 14px; color: var(--ink-2); }
.demo-checks li { display: flex; gap: 10px; }
.demo-checks .mark { flex: none; width: 3.2em; font: 500 13px/1.6 var(--mono); color: var(--muted); }
.demo-checks li[data-check="pass"] .mark { color: var(--success); }
.demo-verdict { margin-top: 8px; min-height: 1.6em; font-size: 14px; font-weight: 600; color: var(--ink); }

/* ---------------------------------------------------------------- sections */

.section { padding: 96px 0; }
.section--sunken { background: var(--sunken); }
.section-title { font-size: clamp(1.65rem, 1.15rem + 1.5vw, 2.35rem); line-height: 1.12; letter-spacing: -0.025em; max-width: 24ch; }
.section-lead { margin-top: 14px; max-width: 62ch; font-size: 17px; }
.body-text { margin-top: 14px; max-width: 58ch; }
.aside-note { margin-top: 32px; max-width: 65ch; font-size: 15px; color: var(--muted); }

/* how it works */
.parts { display: grid; grid-template-columns: 1fr 1fr; gap: 48px; margin-top: 48px; }
.part { padding-top: 20px; border-top: 2px solid var(--line-2); }
.part--1 { border-top-color: var(--accent); }
.part-range { font: 500 13px var(--mono); color: var(--muted); }
.part-title { margin: 6px 0 10px; font-size: 21px; letter-spacing: -0.015em; }
.part-body { max-width: 52ch; }

/* syllabus: the route bar */
.route { margin-top: 44px; }
.route-bar { list-style: none; display: flex; gap: 3px; height: 48px; }
.seg { flex-basis: 0; min-width: 0; }
.seg a {
  display: grid; place-items: center; height: 100%;
  border-radius: 4px; text-decoration: none;
  font: 500 13px var(--mono);
  transition: filter 0.15s, transform 0.15s var(--ease);
}
.seg a:hover { filter: brightness(1.08); transform: translateY(-2px); }
.seg--p1 a { background: var(--seg-1); color: var(--seg-1-ink); }
.seg--p2 a { background: var(--seg-2); color: var(--seg-2-ink); }
.seg--p3 a { background: var(--seg-3); color: var(--seg-3-ink); }
.seg--p4 a { background: var(--seg-4); color: var(--seg-4-ink); }
.seg--free a { background: var(--accent); color: var(--accent-ink); }
.route-scale { position: relative; height: 22px; margin-top: 6px; font: 400 12px var(--mono); color: var(--muted); }
.route-scale span { position: absolute; top: 0; }
.route-scale span:first-child { left: 0; }
.route-scale span:last-child { right: 0; }
.route-scale .route-split { left: calc(71 / 171 * 100%); }
.route-scale .route-split--3 { left: calc(109 / 171 * 100%); }
.route-legend { list-style: none; display: flex; flex-wrap: wrap; gap: 8px 24px; margin-top: 14px; font-size: 14px; color: var(--ink-2); }
.route-legend li { display: flex; align-items: center; gap: 8px; }
.key { width: 12px; height: 12px; border-radius: 3px; }
.key--free { background: var(--accent); }
.key--p1 { background: var(--seg-1); }
.key--p2 { background: var(--seg-2); }
.key--p3 { background: var(--seg-3); }
.key--p4 { background: var(--seg-4); }

/* syllabus: the blocks */
.syl-bar { display: flex; justify-content: flex-end; margin-top: 40px; }
.syl-cols { display: grid; grid-template-columns: 1fr 1fr; gap: 48px; margin-top: 8px; align-items: start; }
.syl-col-title ~ .syl-col-title { margin-top: 32px; }
.syl-col-title { font-size: 15px; color: var(--muted); font-weight: 500; padding-bottom: 10px; border-bottom: 1px solid var(--line-2); }
.syl-mod { border-bottom: 1px solid var(--line); }
.syl-mod summary {
  display: grid; grid-template-columns: 26px minmax(0, 1fr) auto 14px; gap: 14px; align-items: center;
  padding: 14px 0; cursor: pointer; list-style: none;
}
.syl-mod summary::-webkit-details-marker { display: none; }
.syl-mod summary::after {
  content: ""; width: 8px; height: 8px; justify-self: center;
  border-right: 1.5px solid var(--muted); border-bottom: 1.5px solid var(--muted);
  transform: rotate(45deg) translateY(-2px); transition: transform 0.2s var(--ease);
}
.syl-mod[open] summary::after { transform: rotate(225deg) translateY(-2px); }
.syl-mod summary:hover .syl-title { color: var(--accent); }
.syl-mod:target summary .syl-title { color: var(--accent); }
.syl-letter { font: 600 15px var(--mono); color: var(--accent); }
.syl-meta { display: grid; gap: 2px; min-width: 0; }
.syl-title { font-weight: 600; color: var(--ink); transition: color 0.15s; }
.syl-sum { font-size: 14px; color: var(--muted); }
.syl-range { font: 400 12px/1.5 var(--mono); color: var(--muted); text-align: right; white-space: nowrap; }
.tag-free { margin-left: 6px; font: 500 12px var(--mono); color: var(--accent); }
.syl-topics { list-style: none; display: flex; flex-wrap: wrap; gap: 6px 8px; padding: 0 0 18px 40px; }
.syl-topics li {
  padding: 3px 8px; border: 1px solid var(--line); border-radius: 6px;
  background: var(--surface); font: 400 13px var(--mono); color: var(--ink-2);
}

/* checks: copy on top, the script full width under it, so its lines fit */
.checks-copy { max-width: 760px; }
.checks-grid .code-file { margin-top: 36px; }
.code-file { margin: 0; background: var(--surface); border: 1px solid var(--line); border-radius: 10px; overflow: hidden; min-width: 0; }
.code-name { padding: 10px 16px; border-bottom: 1px solid var(--line); font: 400 12px var(--mono); color: var(--muted); }
.code { margin: 0; padding: 16px; overflow-x: auto; font: 400 13px/1.75 var(--mono); color: var(--ink); }
.code code { padding: 0; border: 0; background: none; font-size: inherit; white-space: pre; }

/* inside a step */
.anatomy {
  list-style: none; margin-top: 40px;
  display: grid; grid-template-columns: 1fr 1fr; grid-template-rows: repeat(5, auto);
  grid-auto-flow: column; column-gap: 48px;
}
.anatomy li { display: grid; grid-template-columns: 32px minmax(0, 1fr); gap: 8px; padding: 18px 0; border-top: 1px solid var(--line-2); }
.anatomy-n { font: 500 14px/1.6 var(--mono); color: var(--accent); }
.anatomy-h { font-size: 16px; }
.anatomy-p { margin-top: 4px; font-size: 15px; }

/* faq */
.faq { margin-top: 32px; border-top: 1px solid var(--line); }
.faq-item { border-bottom: 1px solid var(--line); }
.faq-item summary {
  display: flex; justify-content: space-between; align-items: center; gap: 24px;
  padding: 18px 0; cursor: pointer; list-style: none;
  font-size: 17px; font-weight: 500; color: var(--ink);
}
.faq-item summary::-webkit-details-marker { display: none; }
.faq-item summary::after { content: "+"; flex: none; font: 400 20px/1 var(--mono); color: var(--muted); transition: transform 0.2s var(--ease); }
.faq-item[open] summary::after { transform: rotate(45deg); }
.faq-item summary:hover { color: var(--accent); }
.faq-item p { padding: 0 0 20px; max-width: 65ch; }

/* waitlist */
.waitlist-grid { display: grid; grid-template-columns: minmax(0, 1fr) minmax(0, 1fr); gap: 56px; align-items: center; }
.waitlist-form { padding: 28px; background: var(--surface); border: 1px solid var(--line); border-radius: 10px; }

/* footer */
.site-footer { border-top: 1px solid var(--line); padding: 28px 0; font-size: 14px; color: var(--muted); }
.footer-inner { display: flex; flex-wrap: wrap; align-items: center; gap: 16px 28px; }
.footer-legal { display: flex; gap: 20px; margin-right: auto; }
.footer-legal a, .footer-copy a { text-decoration: none; }
.footer-legal a:hover, .footer-copy a:hover { color: var(--ink); text-decoration: underline; }

/* ---------------------------------------------------------------- motion */

.js [data-reveal] { opacity: 0; transform: translateY(14px); transition: opacity 0.6s var(--ease), transform 0.6s var(--ease); }
.js [data-reveal].is-visible { opacity: 1; transform: none; }
.demo-checks li { transition: color 0.2s; }

@media (prefers-reduced-motion: reduce) {
  .js [data-reveal] { opacity: 1; transform: none; transition: none; }
  .seg a, .btn, .syl-mod summary::after, .faq-item summary::after { transition: none; }
  .seg a:hover { transform: none; }
}

/* ---------------------------------------------------------------- responsive */

@media (max-width: 1023px) {
  .hero-grid { grid-template-columns: 1fr; gap: 40px; }
  .hero-sub { max-width: 56ch; }
  .waitlist-grid { grid-template-columns: 1fr; gap: 32px; }
}

@media (max-width: 860px) {
  .site-nav { display: none; }
  .header-tools { margin-left: auto; }
}

@media (max-width: 767px) {
  :root { --gutter: 16px; }
  .hero { padding: 36px 0 64px; }
  .hero-sub { font-size: 17px; margin: 16px 0 24px; }
  .section { padding: 64px 0; }
  .field-row { grid-template-columns: 1fr; }
  .parts, .syl-cols { grid-template-columns: 1fr; gap: 32px; }
  .anatomy { grid-template-columns: 1fr; grid-template-rows: none; grid-auto-flow: row; }
  .route-bar { height: 40px; gap: 2px; }
  .seg a { font-size: 11px; border-radius: 3px; }
  .syl-topics { padding-left: 0; }
  .demo-head { flex-direction: column; gap: 2px; }
  .demo-body { padding: 14px; }
  .term { font-size: 12px; white-space: pre-wrap; overflow-wrap: anywhere; }
  .waitlist-form { padding: 20px; }
  .header-inner { gap: 12px; }
  .header-tools { gap: 6px; }
}

@media (max-width: 380px) {
  .header-tools .btn-sm { padding: 0 10px; font-size: 13px; }
}