/* styles.css — Executable Tutorial Player · dark IDE theme */

:root {
  --bg: #0a0d12;
  --bg-panel: #0d1117;
  --bg-elev: #11161d;
  --surface: #161b22;
  --surface-2: #1b2230;
  --border: #21262d;
  --border-2: #30363d;
  --text: #e6edf3;
  --text-2: #8b949e;
  --text-3: #6e7681;
  --accent: #7ab8ff;
  --pass: #3fb950;
  --pass-2: #56d364;
  --fail: #f85149;
  --skip: #d29922;
  --mono: 'JetBrains Mono', ui-monospace, monospace;
  --sans: 'Public Sans', system-ui, sans-serif;
  --font-scale: 1;
}

* { box-sizing: border-box; }
html, body, #root { height: 100%; margin: 0; }
body {
  background: var(--bg);
  color: var(--text);
  font-family: var(--sans);
  -webkit-font-smoothing: antialiased;
  overflow: hidden;
}
::selection { background: color-mix(in oklab, var(--accent) 35%, transparent); }

button { font-family: inherit; cursor: pointer; border: none; background: none; color: inherit; }
code, pre, .mono { font-family: var(--mono); }

/* scrollbars */
::-webkit-scrollbar { width: 10px; height: 10px; }
::-webkit-scrollbar-thumb { background: #21262d; border-radius: 6px; border: 2px solid var(--bg-panel); }
::-webkit-scrollbar-thumb:hover { background: #30363d; }
::-webkit-scrollbar-track { background: transparent; }

/* ── App shell ──────────────────────────────────────────────────────── */
.app { display: flex; flex-direction: column; height: 100vh; }

.topbar {
  height: 50px; flex: none;
  display: flex; align-items: center; justify-content: space-between;
  padding: 0 16px;
  background: linear-gradient(180deg, #0d1117, #0a0d12);
  border-bottom: 1px solid var(--border);
}
.tb-left { display: flex; align-items: center; gap: 10px; }
.tb-logo { color: var(--accent); font-size: 18px; }
.tb-name { font-family: var(--mono); font-size: 13px; font-weight: 600; letter-spacing: .3px; }
.tb-file {
  font-family: var(--mono); font-size: 12px; color: var(--text-2);
  background: var(--surface); border: 1px solid var(--border); border-radius: 6px;
  padding: 3px 9px;
}
.tb-right { display: flex; align-items: center; gap: 10px; }
.tb-tally { display: flex; gap: 10px; font-family: var(--mono); font-size: 12px; align-items: center; }
.tally-pass { color: var(--pass-2); }
.tally-fail { color: var(--fail); }
.tally-skip { color: var(--skip); }
.tb-btn {
  font-family: var(--mono); font-size: 12px; color: var(--text);
  background: var(--surface); border: 1px solid var(--border-2); border-radius: 6px;
  padding: 6px 12px; transition: .15s; white-space: nowrap;
}
.tb-btn:hover { background: var(--surface-2); border-color: var(--accent); }
.tb-btn-ghost { background: transparent; color: var(--text-2); }
.tb-btn-ghost:hover { color: var(--text); }

.main { flex: 1; display: flex; min-height: 0; }

/* ── Sidebar ────────────────────────────────────────────────────────── */
.sidebar {
  width: 272px; flex: none; overflow-y: auto;
  background: var(--bg-panel); border-right: 1px solid var(--border);
  display: flex; flex-direction: column;
}
.sb-head { padding: 18px 18px 14px; border-bottom: 1px solid var(--border); }
.sb-kicker { font-family: var(--mono); font-size: 10px; letter-spacing: 2px; color: var(--text-3); }
.sb-title { font-size: 15px; font-weight: 600; margin-top: 6px; line-height: 1.35; }
.sb-stats { font-family: var(--mono); font-size: 11px; color: var(--text-2); margin-top: 10px; display: flex; gap: 6px; flex-wrap: wrap; }
.sb-dot { color: var(--text-3); }

.sb-nav { padding: 10px 10px 28px; }
.sb-group { margin-bottom: 4px; }
.sb-group-title {
  display: flex; align-items: center; gap: 8px;
  padding: 12px 8px 6px;
}
.sb-stepno {
  font-family: var(--mono); font-size: 10px; font-weight: 700;
  color: var(--accent); background: color-mix(in oklab, var(--accent) 12%, transparent);
  border: 1px solid color-mix(in oklab, var(--accent) 30%, transparent);
  padding: 1px 5px; border-radius: 4px; flex: none;
}
.sb-group-label { font-size: 12px; font-weight: 600; color: var(--text-2); line-height: 1.3; }
.sb-items { display: flex; flex-direction: column; gap: 1px; }
.sb-item {
  display: flex; align-items: center; gap: 9px; width: 100%; text-align: left;
  padding: 6px 10px 6px 14px; border-radius: 6px; color: var(--text-2);
  font-size: 12.5px; transition: .12s; position: relative;
}
.sb-item:hover { background: var(--surface); color: var(--text); }
.sb-item-active { background: var(--surface-2); color: var(--text); }
.sb-item-active .sb-item-dot { background: var(--accent); box-shadow: 0 0 8px var(--accent); }
.sb-item-dot { width: 5px; height: 5px; border-radius: 50%; background: #30363d; flex: none; }
.sb-item-label { flex: 1; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.sb-mark { font-family: var(--mono); font-size: 11px; flex: none; }
.sb-mark-pass { color: var(--pass); }
.sb-mark-fail { color: var(--fail); }
.sb-mark-done { color: var(--text-3); }

/* ── Panes ──────────────────────────────────────────────────────────── */
.panes { flex: 1; display: flex; min-width: 0; }
.reader, .exec { flex: 1 1 50%; display: flex; flex-direction: column; min-width: 0; }
.exec { background: #08090c; }
.pane-divider { width: 1px; background: var(--border); flex: none; }

.pane-head {
  height: 34px; flex: none; display: flex; align-items: center; gap: 10px;
  padding: 0 16px; border-bottom: 1px solid var(--border);
  background: var(--bg-panel);
}
.pane-label { font-family: var(--mono); font-size: 11px; letter-spacing: 1.5px; text-transform: uppercase; color: var(--text-2); }
.pane-hint { font-size: 11px; color: var(--text-3); }
.exec-label { color: var(--accent); }
.exec-head { background: #0a0c10; justify-content: space-between; }
.exec-meta { display: flex; align-items: center; gap: 12px; }
.exec-wd { font-family: var(--mono); font-size: 11px; color: var(--text-3); white-space: nowrap; }
.exec-failflag {
  font-family: var(--mono); font-size: 10px; color: var(--fail);
  border: 1px solid color-mix(in oklab, var(--fail) 40%, transparent);
  background: color-mix(in oklab, var(--fail) 12%, transparent);
  padding: 1px 6px; border-radius: 4px;
}
.exec-replay { font-family: var(--mono); font-size: 11px; color: var(--text-2); transition: .12s; }
.exec-replay:hover { color: var(--accent); }

.reader-scroll { flex: 1; overflow-y: auto; }
.reader-inner { max-width: 760px; margin: 0 auto; padding: 30px 40px 80px; font-size: calc(15px * var(--font-scale)); }

.reader-crumb { display: flex; align-items: center; gap: 10px; margin-bottom: 22px; flex-wrap: wrap; }
.reader-stepno {
  font-family: var(--mono); font-size: 11px; font-weight: 700; letter-spacing: 1px;
  color: var(--accent); background: color-mix(in oklab, var(--accent) 12%, transparent);
  border: 1px solid color-mix(in oklab, var(--accent) 30%, transparent);
  padding: 2px 8px; border-radius: 5px;
}
.reader-section { font-size: 13px; color: var(--text-2); font-weight: 600; }
.reader-cont { font-size: 12px; color: var(--text-3); font-family: var(--mono); }
.reader-lead {
  margin-bottom: 22px; padding: 14px 0 18px; border-bottom: 1px solid var(--border);
}
.reader-lead .md { color: var(--text-2); font-size: .96em; }
.reader-lead .md > *:first-child { margin-top: 0; }

/* ── Intro card ─────────────────────────────────────────────────────── */
.intro-card { padding-top: 48px; }
.intro-kicker { font-family: var(--mono); font-size: 11px; letter-spacing: 3px; color: var(--accent); }
.intro-title { font-size: 34px; line-height: 1.15; margin: 14px 0 20px; font-weight: 700; letter-spacing: -.5px; }
.intro-md { color: var(--text-2); font-size: 15px; }
.intro-callout {
  display: flex; flex-direction: column; gap: 4px; margin: 24px 0;
  padding: 16px 18px; border-radius: 10px; background: var(--surface);
  border: 1px solid var(--border); border-left: 3px solid var(--accent);
}
.intro-callout-k { font-family: var(--mono); font-size: 11px; letter-spacing: 1px; text-transform: uppercase; color: var(--accent); }
.intro-callout-v { font-size: 15px; color: var(--text); }
.intro-learn, .intro-prereq { margin-top: 24px; }
.intro-learn-h { font-size: 13px; font-weight: 700; text-transform: uppercase; letter-spacing: 1px; color: var(--text-2); margin-bottom: 10px; }
.intro-learn ul, .intro-prereq ul { margin: 0; padding-left: 0; list-style: none; display: flex; flex-direction: column; gap: 8px; }
.intro-learn li, .intro-prereq li { display: flex; gap: 10px; align-items: baseline; }
.intro-learn li::before, .intro-prereq li::before { content: "▸"; color: var(--accent); font-size: 12px; flex: none; }
.intro-learn li .md, .intro-prereq li .md { font-size: 14px; }
.intro-learn li .md p, .intro-prereq li .md p { margin: 0; }

/* ── Markdown ───────────────────────────────────────────────────────── */
.md { line-height: 1.7; color: var(--text); }
.md > *:first-child { margin-top: 0; }
.md h1 { font-size: 1.7em; margin: .6em 0 .5em; font-weight: 700; letter-spacing: -.4px; }
.md h2 { font-size: 1.4em; margin: 1.1em 0 .5em; font-weight: 700; padding-bottom: .25em; border-bottom: 1px solid var(--border); }
.md h3 { font-size: 1.18em; margin: 1.2em 0 .5em; font-weight: 650; color: var(--text); }
.md h4 { font-size: 1.02em; margin: 1.1em 0 .4em; font-weight: 650; color: var(--text-2); }
.md p { margin: .7em 0; }
.md a { color: var(--accent); text-decoration: none; border-bottom: 1px solid color-mix(in oklab, var(--accent) 35%, transparent); }
.md a:hover { border-bottom-color: var(--accent); }
.md strong { color: #fff; font-weight: 650; }
.md ul, .md ol { margin: .7em 0; padding-left: 1.4em; }
.md li { margin: .35em 0; }
.md li::marker { color: var(--text-3); }
.md hr { border: none; border-top: 1px solid var(--border); margin: 1.6em 0; }

.md :not(pre) > code {
  font-family: var(--mono); font-size: .86em;
  background: var(--surface); border: 1px solid var(--border);
  padding: .12em .42em; border-radius: 5px; color: #e3b7ff;
  color: color-mix(in oklab, var(--accent) 80%, #fff 20%);
}
.md pre {
  background: #0a0d12; border: 1px solid var(--border-2); border-radius: 9px;
  padding: 14px 16px; overflow-x: auto; margin: 1em 0; font-size: .82em; line-height: 1.6;
  position: relative;
}
.md pre code { font-family: var(--mono); background: none; border: none; padding: 0; color: #c9d1d9; }

.md blockquote {
  margin: 1em 0; padding: 2px 16px; border-left: 3px solid var(--skip);
  background: color-mix(in oklab, var(--skip) 7%, transparent); border-radius: 0 8px 8px 0;
  color: var(--text-2);
}
.md blockquote strong { color: var(--skip); }
.md blockquote p { margin: .5em 0; }

.md table { border-collapse: collapse; width: 100%; margin: 1em 0; font-size: .85em; display: block; overflow-x: auto; }
.md th, .md td { border: 1px solid var(--border-2); padding: 8px 12px; text-align: left; vertical-align: top; }
.md th { background: var(--surface); font-weight: 650; color: var(--text); }
.md tr:nth-child(even) td { background: rgba(255,255,255,.015); }
.md img { max-width: 100%; }

/* ── Terminal ───────────────────────────────────────────────────────── */
.term-scroll { flex: 1; overflow-y: auto; }
.term-body {
  font-family: var(--mono); font-size: calc(12.5px * var(--font-scale)); line-height: 1.65;
  padding: 18px 18px 80px; min-height: 100%;
}
.t-idle { color: var(--text-3); display: flex; align-items: center; gap: 10px; padding: 30px 4px; font-style: italic; }
.t-idle-dot { width: 7px; height: 7px; border-radius: 50%; background: var(--text-3); }

.t-note { color: var(--text-3); margin: 6px 0 2px; white-space: pre-wrap; }

.t-prompt { display: flex; gap: 10px; margin-top: 12px; align-items: flex-start; }
.t-prompt.t-dim { opacity: .6; }
.t-prompt.t-extra { margin-top: 4px; }
.t-dollar { color: var(--accent); flex: none; user-select: none; }
.t-extra .t-dollar { color: var(--text-3); }
.t-cmd { margin: 0; white-space: pre-wrap; word-break: break-word; color: #e6edf3; flex: 1; }

.t-run { display: flex; align-items: center; gap: 9px; margin: 4px 0 2px; padding-left: 20px; }
.t-run-small { opacity: .8; }
.t-spin { color: var(--accent); width: 12px; display: inline-block; }
.t-spin-sm { font-size: .9em; }
.t-mark { width: 12px; display: inline-block; text-align: center; flex: none; font-weight: 700; }
.t-mark-pass { color: var(--pass-2); }
.t-mark-fail { color: var(--fail); }
.t-mark-skip { color: var(--text-3); }
.t-run-text { color: var(--text-2); white-space: nowrap; }
.t-run-pass .t-run-text { color: var(--pass); }
.t-run-fail .t-run-text { color: var(--fail); font-weight: 600; }

.t-asserthead { color: var(--text-3); margin: 8px 0 3px; padding-left: 20px; font-size: .92em; }
.t-assert { display: flex; gap: 9px; padding-left: 20px; align-items: flex-start; margin: 1px 0; }
.t-assert-text { margin: 0; white-space: pre-wrap; word-break: break-word; color: var(--text-2); flex: 1; }
.t-assert-pass .t-assert-text { color: color-mix(in oklab, var(--pass) 75%, var(--text)); }

.t-check { display: flex; gap: 9px; padding-left: 20px; align-items: center; margin: 4px 0; }
.t-check-text { color: var(--text-2); }
.t-check-pass .t-check-text { color: color-mix(in oklab, var(--pass) 70%, var(--text)); }

.t-ui { display: flex; gap: 9px; padding-left: 20px; align-items: baseline; margin: 2px 0; }
.t-ui-label { color: var(--text); }
.t-ui-pass .t-ui-label { color: color-mix(in oklab, var(--pass) 60%, var(--text)); }
.t-ui-name { color: var(--text-3); font-size: .9em; }

.t-skip { display: flex; gap: 9px; padding-left: 0; align-items: center; margin: 3px 0; opacity: .6; }
.t-skip-text { color: var(--text-3); }

.t-file { margin: 12px 0 6px; }
.t-file-head { display: flex; align-items: center; gap: 7px; color: var(--text-2); margin-bottom: 4px; }
.t-file-icon { color: var(--accent); }
.t-file-path { color: var(--accent); }
.t-file-lang { margin-left: auto; font-size: .85em; color: var(--text-3); border: 1px solid var(--border); padding: 0 6px; border-radius: 4px; }
.t-file-body {
  margin: 0; background: #0c0f15; border: 1px solid var(--border); border-left: 2px solid color-mix(in oklab, var(--accent) 40%, transparent);
  border-radius: 7px; padding: 12px 14px; overflow-x: auto; max-height: 320px; overflow-y: auto;
  font-size: .94em; line-height: 1.55; color: #c9d1d9;
}
.t-file-binary { color: var(--text-3); font-style: italic; padding: 8px 0; }

.t-summary { display: flex; gap: 16px; margin: 16px 0 4px; padding: 8px 0 0; border-top: 1px dashed var(--border-2); }
.t-sum-pass { color: var(--pass-2); }
.t-sum-fail { color: var(--fail); }
.t-sum-skip { color: var(--skip); }

/* ── Controls ───────────────────────────────────────────────────────── */
.controls {
  height: 58px; flex: none; display: flex; align-items: center; gap: 20px;
  padding: 0 18px; border-top: 1px solid var(--border); background: var(--bg-panel);
}
.ctrl-left { display: flex; align-items: center; gap: 7px; }
.ctrl-btn {
  width: 34px; height: 34px; border-radius: 8px; border: 1px solid var(--border-2);
  background: var(--surface); color: var(--text); font-size: 14px; display: grid; place-items: center; transition: .12s;
}
.ctrl-btn:hover:not(:disabled) { border-color: var(--accent); color: var(--accent); }
.ctrl-btn:disabled { opacity: .3; cursor: default; }
.ctrl-play {
  width: 40px; height: 40px; border-radius: 10px; background: var(--accent); color: #0a0d12;
  font-size: 13px; display: grid; place-items: center; transition: .12s; font-weight: 700;
}
.ctrl-play:hover { filter: brightness(1.12); }
.ctrl-play.is-playing { background: var(--surface-2); color: var(--accent); border: 1px solid var(--accent); }

.ctrl-progress { flex: 1; display: flex; align-items: center; gap: 14px; }
.ctrl-count { font-family: var(--mono); font-size: 12px; color: var(--text-2); flex: none; }
.ctrl-track { flex: 1; height: 4px; background: var(--surface); border-radius: 3px; overflow: hidden; }
.ctrl-fill { height: 100%; background: linear-gradient(90deg, color-mix(in oklab,var(--accent) 60%, transparent), var(--accent)); border-radius: 3px; transition: width .35s ease; }

.ctrl-right { display: flex; align-items: center; gap: 12px; }
.ctrl-seg, .ctrl-speed { display: flex; background: var(--surface); border: 1px solid var(--border-2); border-radius: 8px; overflow: hidden; }
.ctrl-seg button, .ctrl-speed button {
  font-family: var(--mono); font-size: 11px; padding: 6px 11px; color: var(--text-2); transition: .12s;
}
.ctrl-seg button:hover, .ctrl-speed button:hover { color: var(--text); }
.ctrl-seg .seg-on, .ctrl-speed .spd-on { background: var(--accent); color: #0a0d12; font-weight: 600; }

/* ── Full markdown overlay ──────────────────────────────────────────── */
.fm-overlay { position: fixed; inset: 0; z-index: 60; background: var(--bg); display: flex; flex-direction: column; animation: fadein .15s ease; }
@keyframes fadein { from { opacity: 0; } to { opacity: 1; } }
.fm-bar { height: 52px; flex: none; display: flex; align-items: center; justify-content: space-between; padding: 0 18px; border-bottom: 1px solid var(--border); background: var(--bg-panel); }
.fm-title { display: flex; align-items: center; gap: 10px; font-weight: 600; }
.fm-icon { color: var(--accent); font-size: 16px; }
.fm-sub { font-family: var(--mono); font-size: 12px; color: var(--text-3); }
.fm-actions { display: flex; align-items: center; gap: 10px; }
.fm-copy, .fm-close { font-family: var(--mono); font-size: 12px; padding: 6px 12px; border-radius: 7px; border: 1px solid var(--border-2); background: var(--surface); color: var(--text); transition: .12s; }
.fm-copy:hover, .fm-close:hover { border-color: var(--accent); }
.fm-body { flex: 1; overflow-y: auto; }
.fm-inner { max-width: 820px; margin: 0 auto; padding: 40px 48px 100px; }
.fm-source { font-family: var(--mono); font-size: 12.5px; line-height: 1.7; white-space: pre-wrap; word-break: break-word; color: var(--text-2); }

/* ── Landing / uploader ─────────────────────────────────────────────── */
.landing { position: relative; height: 100vh; overflow: auto; display: grid; place-items: center; }
.landing-grid {
  position: absolute; inset: 0;
  background-image: linear-gradient(var(--border) 1px, transparent 1px), linear-gradient(90deg, var(--border) 1px, transparent 1px);
  background-size: 44px 44px; opacity: .25;
  mask-image: radial-gradient(ellipse 70% 60% at 50% 40%, #000 30%, transparent 75%);
}
.landing-inner { position: relative; max-width: 720px; width: 100%; padding: 40px 28px; text-align: center; }
.landing-badge { font-family: var(--mono); font-size: 12px; color: var(--accent); letter-spacing: 1px; margin-bottom: 18px; }
.landing-title { font-size: 40px; font-weight: 700; letter-spacing: -1px; margin: 0 0 16px; }
.landing-sub { color: var(--text-2); font-size: 16px; line-height: 1.6; max-width: 560px; margin: 0 auto 32px; }
.landing-sub code { font-family: var(--mono); font-size: .85em; color: var(--accent); background: var(--surface); padding: .1em .4em; border-radius: 4px; }

.dropzone {
  border: 1.5px dashed var(--border-2); border-radius: 14px; padding: 40px 24px;
  background: var(--bg-panel); cursor: pointer; transition: .15s; max-width: 520px; margin: 0 auto;
}
.dropzone:hover { border-color: var(--accent); background: var(--bg-elev); }
.dz-drag { border-color: var(--accent); background: color-mix(in oklab, var(--accent) 8%, var(--bg-panel)); }
.dz-icon { font-size: 30px; color: var(--accent); margin-bottom: 10px; }
.dz-main { font-size: 16px; margin-bottom: 6px; }
.dz-main b { color: var(--accent); }
.dz-or { font-size: 13px; color: var(--text-3); white-space: nowrap; }
.dz-paste { font-family: var(--mono); color: var(--text-2); border-bottom: 1px solid var(--border-2); font-size: 13px; }
.dz-paste:hover { color: var(--accent); }

.paste-box { max-width: 520px; margin: 14px auto 0; display: flex; flex-direction: column; gap: 8px; }
.paste-box textarea {
  width: 100%; height: 160px; resize: vertical; font-family: var(--mono); font-size: 12px;
  background: var(--bg-panel); border: 1px solid var(--border-2); border-radius: 10px; color: var(--text);
  padding: 12px; line-height: 1.5;
}
.paste-box textarea:focus { outline: none; border-color: var(--accent); }
.paste-go { align-self: flex-end; font-family: var(--mono); font-size: 12px; padding: 8px 14px; border-radius: 8px; background: var(--accent); color: #0a0d12; font-weight: 600; }

.landing-error {
  max-width: 520px; margin: 16px auto 0; color: var(--fail); font-family: var(--mono); font-size: 13px;
  background: color-mix(in oklab, var(--fail) 10%, transparent); border: 1px solid color-mix(in oklab, var(--fail) 30%, transparent);
  border-radius: 8px; padding: 10px 14px; text-align: left;
}

.examples { margin-top: 40px; }
.examples-h { font-family: var(--mono); font-size: 11px; letter-spacing: 1.5px; text-transform: uppercase; color: var(--text-3); margin-bottom: 14px; }
.examples-row { display: flex; gap: 14px; justify-content: center; flex-wrap: wrap; }
.example-card {
  flex: 1 1 240px; max-width: 320px; text-align: left; padding: 16px;
  background: var(--bg-panel); border: 1px solid var(--border-2); border-radius: 12px; transition: .15s;
}
.example-card:hover { border-color: var(--accent); transform: translateY(-2px); background: var(--bg-elev); }
.ex-name { font-family: var(--mono); font-size: 11px; color: var(--text-3); margin-bottom: 8px; word-break: break-all; }
.ex-title { font-size: 14px; font-weight: 600; line-height: 1.4; margin-bottom: 8px; }
.ex-stats { font-family: var(--mono); font-size: 11px; color: var(--accent); }