:root {
  --ink: #e9f0f5;
  --muted: #9aa8b4;
  --dark: #070b12;
  --panel: #0e1622;
  --panel-2: #131f2e;
  --line: #283748;
  --lime: #c5ff48;
  --violet: #a67aff;
  --amber: #ffc26c;
  --ice: #9ee7ff;
  --display: "Unbounded", sans-serif;
  --body: "IBM Plex Sans", sans-serif;
  --mono: "Space Mono", monospace;
  --sidebar-w: 312px;
}

* { box-sizing: border-box; }
[hidden] { display: none !important; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  color: var(--ink);
  background: var(--dark);
  font-family: var(--body);
  line-height: 1.6;
}
a { color: var(--ice); }
button, a { -webkit-tap-highlight-color: transparent; }
:focus-visible { outline: 2px solid var(--lime); outline-offset: 3px; }
h1, h2, h3 { margin-top: 0; }

/* ---------- Shared bits ---------- */

.status-badge {
  display: inline-block;
  padding: 3px 8px;
  border: 1px solid var(--line);
  border-radius: 2px;
  font: 700 9px/1.3 var(--mono);
  letter-spacing: .1em;
  text-transform: uppercase;
  white-space: nowrap;
}
.status-badge[data-status="early-access"] { color: var(--amber); border-color: rgba(255,194,108,.4); }
.status-badge[data-status="to-be-delivered"] { color: var(--amber); border-color: rgba(255,194,108,.4); }

.button {
  display: inline-flex;
  min-height: 46px;
  align-items: center;
  justify-content: center;
  padding: 0 20px;
  border: 1px solid var(--line);
  background: transparent;
  color: var(--ink);
  font: 700 12px var(--mono);
  text-transform: uppercase;
  text-decoration: none;
  cursor: pointer;
  transition: transform .16s ease, border-color .16s ease, background .16s ease;
}
.button:hover { transform: translateY(-2px); border-color: var(--lime); }
.button-primary { color: var(--dark); background: var(--lime); border-color: var(--lime); }
.button-primary:hover { box-shadow: 0 0 26px rgba(197,255,72,.28); }
.button-ghost { background: rgba(7,11,18,.6); }

.language-switch { display: flex; border: 1px solid var(--line); }
.language-switch button {
  padding: 8px 12px;
  color: var(--muted);
  background: transparent;
  border: 0;
  font: 700 11px var(--mono);
  cursor: pointer;
}
.language-switch button[aria-pressed="true"] { color: var(--dark); background: var(--lime); }

/* ---------- Cover (approved pixel-art hero) ---------- */

.cover {
  position: relative;
  display: flex;
  min-height: 100vh;
  min-height: 100svh;
  align-items: center;
  overflow: hidden;
}
.cover-art { position: absolute; inset: 0; width: 100%; height: 100%; object-fit: cover; object-position: center; }
.cover-shade { position: absolute; inset: 0; background: linear-gradient(90deg, rgba(7,11,18,.98) 0%, rgba(7,11,18,.84) 40%, rgba(7,11,18,.12) 74%); }
.cover-copy { position: relative; z-index: 2; width: min(1120px, 100%); padding: clamp(36px, 5vw, 92px) clamp(28px, 8vw, 120px); }
.cover-utility { display: flex; gap: 14px; align-items: center; margin: 0 0 22px; color: var(--muted); font: 700 11px var(--mono); letter-spacing: .1em; text-transform: uppercase; }
.cover h1 { max-width: 16ch; margin: 0 0 22px; font: 700 clamp(40px, 6vw, 84px)/1.02 var(--display); letter-spacing: -.05em; }
.cover-lead { max-width: 600px; margin: 0; color: #c4d0d9; font-size: clamp(18px, 2.1vw, 24px); }
.cover-actions { display: flex; flex-wrap: wrap; gap: 12px; margin: 34px 0 22px; }
.cover-reset { margin: -10px 0 18px; padding: 0; border: 0; border-bottom: 1px solid currentColor; background: transparent; color: var(--muted); font: 700 11px var(--mono); cursor: pointer; }
.cover-reset:hover { color: var(--lime); }
.cover-note { max-width: 560px; margin: 0; color: var(--muted); font: 400 14px var(--body); }
.cover-credit { display: flex; flex-wrap: wrap; gap: 6px; max-width: 560px; margin: 22px 0 0; color: var(--muted); font: 700 11px/1.5 var(--mono); }
.cover-credit [data-i18n="coverMadeBy"]:empty { display: none; }
.cover-credit a { color: var(--ice); text-decoration: none; }
.cover-credit a:hover { color: var(--lime); }
.cover-toolbar { position: absolute; z-index: 2; top: clamp(20px, 4vw, 36px); left: clamp(20px, 4vw, 36px); display: flex; gap: 10px; align-items: stretch; }
.cover-chapters { display: inline-flex; align-items: center; gap: 7px; padding: 0 12px; border: 1px solid var(--line); background: rgba(7,11,18,.6); color: var(--ink); font: 700 11px var(--mono); text-transform: uppercase; cursor: pointer; }
.cover-chapters:hover { border-color: var(--lime); color: var(--lime); }
.cover-picker-scrim { position: fixed; inset: 0; z-index: 40; width: 100%; height: 100%; padding: 0; border: 0; background: rgba(2,6,12,.72); cursor: pointer; }
.cover-chapter-picker { position: fixed; inset: 0 auto 0 0; z-index: 41; display: flex; flex-direction: column; width: min(86vw, var(--sidebar-w)); height: 100vh; height: 100svh; padding: 20px 18px; overflow-y: auto; background: var(--panel); border-right: 1px solid var(--line); box-shadow: 20px 0 50px rgba(0,0,0,.35); }
.cover-picker-head { display: flex; min-height: 42px; align-items: center; justify-content: space-between; gap: 16px; margin-bottom: 18px; padding: 0 4px 14px 12px; border-bottom: 1px solid var(--line); font: 700 12px var(--mono); text-transform: uppercase; }
.cover-picker-close { width: 36px; height: 36px; padding: 0; border: 1px solid var(--line); background: transparent; color: var(--ink); font: 400 24px/1 var(--body); cursor: pointer; }
.cover-picker-close:hover { border-color: var(--lime); color: var(--lime); }
.cover-picker-nav { flex: 0 0 auto; }

/* ---------- App shell ---------- */

.app-shell { display: grid; grid-template-columns: var(--sidebar-w) 1fr; min-height: 100vh; min-height: 100svh; }

.mobile-bar {
  display: none;
  position: sticky;
  top: 0;
  z-index: 30;
  align-items: center;
  gap: 14px;
  padding: 10px 16px;
  background: rgba(7,11,18,.94);
  border-bottom: 1px solid var(--line);
  backdrop-filter: blur(14px);
}
.menu-button { display: inline-flex; gap: 8px; align-items: center; padding: 8px 12px; color: var(--ink); background: transparent; border: 1px solid var(--line); font: 700 11px var(--mono); text-transform: uppercase; cursor: pointer; }
.mobile-title { font: 700 12px var(--mono); letter-spacing: .04em; color: var(--muted); }

.sidebar {
  position: sticky;
  top: 0;
  display: flex;
  flex-direction: column;
  height: 100vh;
  height: 100svh;
  padding: 22px 18px;
  background: var(--panel);
  border-right: 1px solid var(--line);
  overflow-y: auto;
}
.sidebar-head { display: flex; flex-wrap: wrap; gap: 10px; align-items: center; justify-content: space-between; margin-bottom: 20px; }
.brand { display: inline-flex; gap: 9px; align-items: center; padding: 0; color: var(--ink); background: transparent; border: 0; font: 700 12px var(--mono); letter-spacing: .1em; cursor: pointer; }
.brand-mark { color: var(--lime); }

.progress { margin-bottom: 22px; }
.progress-track { height: 4px; background: var(--panel-2); border: 1px solid var(--line); overflow: hidden; }
.progress-fill { height: 100%; width: 0; background: var(--lime); transition: width .3s ease; }
.progress-label { margin: 8px 0 0; color: var(--muted); font: 700 10px var(--mono); letter-spacing: .06em; text-transform: uppercase; }

.chapter-nav { display: flex; flex-direction: column; gap: 12px; flex: 1; }
.chapter-group { display: flex; flex-direction: column; gap: 2px; }
.chapter-group-label { margin: 0 12px 4px; color: var(--muted); font: 700 9px var(--mono); letter-spacing: .08em; text-transform: uppercase; }
.chapter-link {
  display: flex;
  gap: 12px;
  align-items: flex-start;
  padding: 11px 12px;
  text-align: left;
  color: var(--ink);
  background: transparent;
  border: 0;
  border-left: 2px solid transparent;
  cursor: pointer;
  transition: background .14s ease, border-color .14s ease;
}
.chapter-link:hover { background: var(--panel-2); }
.chapter-link.is-current { background: var(--panel-2); border-left-color: var(--lime); }
.home-link { margin-bottom: 10px; border-bottom: 1px solid var(--line); color: var(--ice); }
.home-link .chapter-index { color: var(--lime); }
.chapter-link-no-index { padding-left: 46px; }
.chapter-index { flex-shrink: 0; width: 22px; color: var(--violet); font: 700 11px var(--mono); padding-top: 2px; }
.chapter-link.is-done .chapter-index { color: var(--lime); }
.chapter-text { display: flex; flex-direction: column; gap: 5px; }
.chapter-title { font: 600 14px/1.25 var(--body); }
.chapter-link.is-current .chapter-title { color: var(--lime); }

.sidebar-updates { margin-top: 18px; padding-top: 16px; border-top: 1px solid var(--line); }
.updates-label { margin: 0; color: var(--ink); font: 700 11px var(--mono); letter-spacing: .08em; text-transform: uppercase; }
.updates-note { margin: 8px 0 10px; color: var(--muted); font: 400 12px/1.5 var(--body); }
.updates-field-label { display: block; margin-bottom: 6px; color: var(--ice); font: 700 11px var(--mono); }
.updates-row { display: flex; gap: 8px; }
.updates-input { flex: 1; min-width: 0; padding: 8px 10px; border: 1px solid var(--line); background: transparent; color: var(--ink); font: 400 12px var(--mono); }
.updates-input:focus { outline: none; border-color: var(--lime); }
.updates-input::placeholder { color: var(--muted); }
.updates-submit { padding: 8px 12px; font-size: 11px; white-space: nowrap; }
.updates-privacy { margin: 7px 0 0; color: var(--muted); font: 400 11px/1.45 var(--body); }
.updates-status { margin: 8px 0 0; color: var(--lime); font: 700 11px/1.5 var(--mono); }
.updates-status[data-key="emailError"] { color: var(--amber); }

.sidebar-foot { display: flex; flex-wrap: wrap; align-items: center; justify-content: space-between; gap: 12px; margin-top: 18px; padding-top: 16px; border-top: 1px solid var(--line); }
.sidebar-link { color: var(--muted); font: 700 11px var(--mono); text-decoration: none; }
.sidebar-link:hover { color: var(--ice); }
.sidebar-feedback { flex-basis: 100%; margin-top: 4px; color: var(--amber); text-decoration: underline; text-underline-offset: 3px; }
.sidebar-feedback:hover { color: var(--amber); opacity: .8; }

.scrim { position: fixed; inset: 0; z-index: 25; background: rgba(7,11,18,.6); }

/* ---------- Reader ---------- */

.reader { display: flex; flex-direction: column; height: 100vh; height: 100svh; overflow-y: auto; }
.reader:focus-visible { outline: none; }
.reader-body { width: min(800px, 100%); margin: 0 auto; padding: clamp(32px, 5vw, 72px) clamp(20px, 5vw, 56px) 40px; flex: 1; }
.reader-head { display: flex; flex-direction: column; gap: 14px; margin-bottom: 28px; padding-bottom: 22px; border-bottom: 1px solid var(--line); }
.reader-head .status-badge { align-self: flex-start; }
.reader-body h1 { font: 700 clamp(30px, 4vw, 46px)/1.05 var(--display); letter-spacing: -.04em; }
.reader-h2 { margin: 38px 0 14px; font: 600 clamp(20px, 2.4vw, 26px)/1.2 var(--display); letter-spacing: -.02em; }
.reader-body p { color: #c2cdd6; }
.reader-body .lead { color: var(--ink); font-size: clamp(17px, 1.9vw, 20px); }
.reader-body a { color: var(--ice); text-underline-offset: 3px; }

.bullets { padding-left: 20px; color: #c2cdd6; }
.bullets li { margin: 7px 0; }

/* Route steps */
.route { list-style: none; counter-reset: step; padding: 0; margin: 22px 0; display: grid; gap: 10px; }
.route li { counter-increment: step; position: relative; padding: 16px 18px 16px 56px; background: var(--panel); border: 1px solid var(--line); }
.route li::before { content: counter(step); position: absolute; left: 16px; top: 16px; width: 26px; height: 26px; display: grid; place-items: center; color: var(--dark); background: var(--lime); font: 700 12px var(--mono); }
.route h3 { margin: 0 0 4px; font: 700 16px/1.2 var(--display); }
.route p { margin: 0; color: var(--muted); font-size: 14px; }

/* Code + prompt cards */
.code-block, .prompt-body { margin: 0; padding: 16px; background: #050a11; border: 1px solid var(--line); overflow-x: auto; }
.code-block code, .prompt-body code { font: 400 13px/1.6 var(--mono); color: var(--ink); white-space: pre; }
.code-block { margin: 18px 0; }
.prompt-card { margin: 20px 0; border: 1px solid var(--line); background: var(--panel); }
.prompt-head { display: flex; gap: 12px; align-items: center; justify-content: space-between; flex-wrap: wrap; padding: 12px 14px; border-bottom: 1px solid var(--line); }
.prompt-title { font: 700 11px var(--mono); letter-spacing: .06em; text-transform: uppercase; color: var(--muted); }
.prompt-actions { display: flex; gap: 8px; align-items: center; }
.prompt-card .prompt-body { border: 0; }
.copy-button { padding: 7px 14px; color: var(--dark); background: var(--lime); border: 1px solid var(--lime); font: 700 10px var(--mono); text-transform: uppercase; cursor: pointer; transition: background .14s ease; }
.copy-button.is-copied { background: var(--ice); border-color: var(--ice); }
.download-link { padding: 7px 12px; color: var(--ice); border: 1px solid var(--line); font: 700 10px var(--mono); text-transform: uppercase; text-decoration: none; }
.download-link:hover { border-color: var(--ice); }

/* Pipeline (input -> output chain) */
.pipeline { list-style: none; padding: 0; margin: 22px 0; display: grid; gap: 0; }
.pipeline li { position: relative; padding: 13px 16px; background: var(--panel); border: 1px solid var(--line); font: 600 14px var(--mono); }
.pipeline li + li { margin-top: 22px; }
.pipeline li + li::before { content: "↓"; position: absolute; top: -20px; left: 18px; color: var(--lime); font: 700 14px var(--mono); }

/* Guided lab */
.guided-lab { margin: 28px 0; border: 1px solid var(--line); background: linear-gradient(135deg, rgba(159, 255, 108, .08), rgba(139, 92, 246, .08) 48%, rgba(8, 14, 24, .96)); }
.lab-head { padding: 18px 18px 4px; }
.lab-eyebrow { display: inline-block; margin-bottom: 10px; color: var(--lime); font: 700 10px var(--mono); letter-spacing: .08em; text-transform: uppercase; }
.lab-head h2 { margin: 0 0 8px; font: 700 clamp(24px, 3vw, 34px)/1 var(--display); }
.lab-head p { max-width: 680px; margin: 0; color: #c2cdd6; font-size: 15px; }
.lab-steps { list-style: none; counter-reset: lab; display: grid; gap: 12px; margin: 0; padding: 18px; }
.lab-step { counter-increment: lab; position: relative; padding: 16px; background: rgba(7, 11, 18, .74); border: 1px solid var(--line); }
.lab-step::before { content: counter(lab); position: absolute; top: 16px; right: 16px; color: rgba(232, 238, 244, .18); font: 700 32px/1 var(--mono); }
.lab-step-head { padding-right: 42px; }
.lab-label { color: var(--violet); font: 700 10px var(--mono); letter-spacing: .08em; text-transform: uppercase; }
.lab-step h3 { margin: 8px 0 12px; font: 700 18px/1.15 var(--display); }
.lab-panels { display: grid; grid-template-columns: minmax(0, 1.35fr) minmax(160px, .75fr) minmax(180px, .9fr); gap: 10px; align-items: stretch; }
.lab-panel { min-width: 0; padding: 10px; background: rgba(255, 255, 255, .035); border: 1px solid rgba(232, 238, 244, .09); }
.lab-panel > span { display: block; margin-bottom: 8px; color: var(--lime); font: 700 10px var(--mono); letter-spacing: .08em; text-transform: uppercase; }
.lab-panel p { margin: 0; color: #dce6ef; font-size: 13px; line-height: 1.55; }
.lab-panel code { color: var(--lime); font-family: var(--mono); }
.lab-example { max-width: 100%; margin: 0; padding: 13px 14px; overflow-x: hidden; background: #050a11; border: 1px solid rgba(159, 255, 108, .18); }
.lab-example code { font: 400 12px/1.55 var(--mono); color: #dce6ef; white-space: pre-wrap; overflow-wrap: anywhere; }
.lab-check { color: var(--ink); font-size: 14px; }
.lab-check::before { content: "Check: "; color: var(--amber); font: 700 11px var(--mono); letter-spacing: .05em; text-transform: uppercase; }

@media (max-width: 860px) {
  .lab-panels { grid-template-columns: 1fr; }
}

/* Workflow with times */
.flow { margin: 22px 0; border: 1px solid var(--line); }
.flow-stage { display: flex; gap: 14px; align-items: center; justify-content: space-between; padding: 13px 16px; border-bottom: 1px solid var(--line); }
.flow-name { font-weight: 600; }
.flow-time { flex-shrink: 0; color: var(--ice); font: 700 12px var(--mono); }
.flow-total { margin: 0; padding: 15px 16px; color: var(--lime); background: var(--panel); font: 700 13px var(--mono); }

/* Scorecard */
.scorecard { list-style: none; padding: 0; margin: 22px 0; display: grid; gap: 10px; }
.scorecard li { display: flex; gap: 14px; padding: 15px 16px; background: var(--panel); border: 1px solid var(--line); border-top: 2px solid var(--violet); }
.sc-n { flex-shrink: 0; color: var(--violet); font: 700 18px var(--mono); }
.scorecard h3 { margin: 0 0 4px; font: 700 15px var(--display); }
.scorecard p { margin: 0; color: var(--muted); font-size: 14px; }

/* Card grid (templates, cases) */
.card-grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: 12px; margin: 22px 0; }
.card { display: flex; flex-direction: column; padding: 18px; background: var(--panel); border: 1px solid var(--line); border-top: 2px solid var(--lime); }
.card-tag { color: var(--violet); font: 700 10px var(--mono); letter-spacing: .08em; }
.card h3 { margin: 12px 0 8px; font: 700 17px/1.2 var(--display); }
.card p { margin: 0; color: var(--muted); font-size: 14px; }
.card-foot { margin-top: auto; padding-top: 14px; }

/* Links */
.link-list { list-style: none; padding: 0; margin: 18px 0; }
.link-list li { padding: 9px 0; border-bottom: 1px solid var(--line); }
.link-list a { font-weight: 600; color: var(--ink); text-decoration: none; border-bottom: 1px solid var(--violet); padding-bottom: 1px; }
.link-list a:hover { color: var(--lime); border-color: var(--lime); }
.link-note { color: var(--muted); font-size: 13px; }

/* Note / callout */
.note { margin: 20px 0; padding: 15px 18px; background: var(--panel-2); border-left: 3px solid var(--amber); color: #cdd7df; font-size: 14px; }
.note strong { color: var(--ink); }
.note code { font: 600 12px var(--mono); color: var(--ink); }

.milestone { margin: 0 0 26px; padding: 18px 20px; background: var(--panel-2); border: 1px solid rgba(197,255,72,.4); border-left: 3px solid var(--lime); }
.milestone strong { display: block; color: var(--lime); font: 700 13px var(--mono); text-transform: uppercase; letter-spacing: .06em; margin-bottom: 6px; }
.milestone p { margin: 0 0 14px; color: #cdd7df; font-size: 14px; }
.milestone-actions { display: flex; flex-wrap: wrap; gap: 10px; }
.milestone-invite { margin: 14px 0 0; font-size: 13px; color: var(--muted); }
.milestone-invite a { color: var(--lime); }

/* Reader footer actions */
.reader-foot { position: sticky; bottom: 0; display: flex; gap: 12px; justify-content: space-between; padding: 14px clamp(20px, 5vw, 56px); background: rgba(7,11,18,.92); border-top: 1px solid var(--line); backdrop-filter: blur(12px); }
.reader-foot .button { min-width: 140px; }
.reader-foot #mark-done { margin-left: auto; }
.reader-foot #next-step { margin-left: auto; }
.reader-foot #mark-done:not([hidden]) + #next-step { margin-left: 0; }

/* ---------- Responsive ---------- */

@media (max-width: 860px) {
  .app-shell { grid-template-columns: 1fr; }
  .mobile-bar { display: flex; }
  .sidebar {
    position: fixed;
    top: 0;
    left: 0;
    z-index: 31;
    width: min(86vw, var(--sidebar-w));
    height: 100vh; height: 100svh;
    transform: translateX(-105%);
    transition: transform .22s ease;
  }
  .sidebar.is-open { transform: translateX(0); }
  .reader { height: auto; min-height: calc(100svh - 53px); }
  .reader-foot { position: sticky; }
  .card-grid { grid-template-columns: 1fr; }
}

@media (max-width: 560px) {
  .cover-art { object-position: 86% center; }
  .cover-shade { background: linear-gradient(90deg, rgba(4, 9, 20, 0.99) 0%, rgba(4, 9, 20, 0.94) 48%, rgba(4, 9, 20, 0.62) 74%, rgba(4, 9, 20, 0.28) 100%); }
  .cover-actions .button { width: 100%; }
  .cover-actions { width: 100%; }
  .reader-foot { flex-wrap: wrap; }
  .reader-foot .button { min-width: 0; flex: 1 1 42%; padding: 0 12px; }
  .reader-foot #mark-done { margin-left: 0; }
  .flow-stage { flex-direction: column; align-items: flex-start; gap: 4px; }
}

@media (max-width: 560px) and (max-height: 720px) {
  .cover { align-items: flex-start; }
  .cover-copy { padding-top: 96px; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after { transition: none !important; animation: none !important; }
}