:root {
  --base-font: 20px;
  --bg: #f5f6fb;
  --card: #ffffff;
  --ink: #1c2230;
  --soft-ink: #5a6275;
  --accent: #4356d6;
  --accent-dark: #2f3fb0;
  --accent-2: #7c3aed;
  --accent-soft: #edeefb;
  --line: #e2e4ef;
  --warn-bg: #fff6e5;
  --warn-line: #e0b84c;
  --good-bg: #eef2ff;
  --good-line: #6b8af0;
  --note-bg: #fff6e5;
  --note-line: #e0b84c;
}

html[data-theme="dark"] {
  --bg: #12141c;
  --card: #1b1f2b;
  --ink: #e8eaf3;
  --soft-ink: #a6acc0;
  --accent: #6f86ff;
  --accent-dark: #9db2ff;
  --accent-2: #b794f6;
  --accent-soft: #232a3c;
  --line: #2c3346;
  --warn-bg: #2c2415;
  --warn-line: #b08a3a;
  --good-bg: #17233b;
  --good-line: #4d6fd0;
  --note-bg: #2c2415;
  --note-line: #b08a3a;
}
.theme-btn { background: #fff; color: #2f3fb0; border: 2px solid #fff; border-radius: 8px;
  font-size: 1rem; line-height: 1; cursor: pointer; padding: 0.25rem 0.5rem; }
.theme-btn:focus-visible { outline: 3px solid #ffce5c; outline-offset: 2px; }

* { box-sizing: border-box; }
html { font-size: var(--base-font); }
body { margin: 0; background: var(--bg); color: var(--ink);
  font-family: -apple-system, "Segoe UI", Roboto, Helvetica, Arial, sans-serif; line-height: 1.6; }
.wrap { max-width: 760px; margin: 0 auto; padding: 0 1rem 4rem; }

/* Top bar + text size control */
.topbar { position: sticky; top: 0; z-index: 10; background: linear-gradient(135deg, var(--accent), var(--accent-2)); color: #fff;
  padding: 0.6rem 1rem; display: flex; flex-wrap: wrap; gap: 0.5rem; align-items: center; justify-content: space-between; }
.topbar .brand { font-weight: 700; font-size: 1rem; color: #fff; text-decoration: none; }
.topbar .brand:hover { text-decoration: underline; }

/* Persistent top navigation bar (added by app.js) */
.topnav { flex-basis: 100%; display: flex; flex-wrap: wrap; gap: 0.25rem 0.35rem;
  margin-top: 0.55rem; padding-top: 0.5rem; border-top: 1px solid rgba(255,255,255,0.3); }
.topnav a { color: #fff; text-decoration: none; font-weight: 600; font-size: 0.95rem;
  padding: 0.35rem 0.7rem; border-radius: 8px; line-height: 1.2; }
.topnav a:hover { background: rgba(255,255,255,0.18); }
.topnav a.active { background: #fff; color: #2f3fb0; }
.topnav a:focus-visible { outline: 3px solid #ffce5c; outline-offset: 2px; }
.sizer { display: flex; align-items: center; gap: 0.4rem; }
.sizer span { font-size: 0.85rem; }
.sizer button { background: #fff; color: #2f3fb0; border: 2px solid #fff; border-radius: 8px;
  font-weight: 700; cursor: pointer; padding: 0.25rem 0.55rem; line-height: 1; }
.sizer button.s { font-size: 0.85rem; }
.sizer button.m { font-size: 1rem; }
.sizer button.l { font-size: 1.2rem; }
.sizer button:focus-visible { outline: 3px solid #ffce5c; outline-offset: 2px; }

/* Headings + text */
h1 { font-size: 2rem; line-height: 1.2; margin: 1.4rem 0 0.4rem; }
.subtitle { font-size: 1.15rem; color: var(--soft-ink); margin-top: 0; }
h2 { font-size: 1.5rem; margin: 2.4rem 0 0.6rem; padding-top: 0.4rem; }
h3 { font-size: 1.2rem; margin: 1.4rem 0 0.4rem; }
p { margin: 0.7rem 0; }
.lead { font-size: 1.1rem; }
a { color: var(--accent-dark); }

.back { display: inline-block; margin: 1.2rem 0 0; color: var(--accent-dark); font-weight: 700; text-decoration: none; }
.back:hover { text-decoration: underline; }

section.card { background: var(--card); border: 1px solid var(--line); border-radius: 14px;
  padding: 1.2rem 1.3rem 1.4rem; margin: 1.4rem 0; box-shadow: 0 1px 3px rgba(0,0,0,0.04); }

/* Step chooser (collapsible) */
.choose { list-style: none; padding: 0; margin: 1rem 0 0; }
.choose > li { border: 1px solid var(--line); border-radius: 12px; margin-bottom: 0.8rem; overflow: hidden; }
.choose summary { cursor: pointer; padding: 0.9rem 1rem; font-weight: 700; font-size: 1.1rem;
  background: var(--accent-soft); list-style: none; }
.choose summary::-webkit-details-marker { display: none; }
.choose summary::after { content: " ▸"; color: var(--accent); }
.choose details[open] > summary::after, details[open].x > summary::after { content: " ▾"; }
.choose .body { padding: 0.4rem 1rem 1rem; }

/* Copyable prompt rows */
.prompt { display: flex; gap: 0.6rem; align-items: stretch; background: var(--accent-soft);
  border: 1px solid var(--line); border-radius: 10px; padding: 0.7rem 0.8rem; margin: 0.6rem 0; }
.prompt .text { flex: 1; font-size: 1.05rem; }
.prompt button { flex: 0 0 auto; align-self: center; background: var(--accent); color: #fff; border: none;
  border-radius: 8px; padding: 0.55rem 0.8rem; font-weight: 700; cursor: pointer; font-size: 0.95rem; white-space: nowrap; }
.prompt button:active { background: var(--accent-dark); }
.prompt button.copied { background: var(--good-line); }
.prompt button:focus-visible { outline: 3px solid #ffce5c; outline-offset: 2px; }

/* Magic chips */
.chips { display: flex; flex-wrap: wrap; gap: 0.5rem; margin: 0.8rem 0; }
.chip { background: var(--card); border: 2px solid var(--accent); color: var(--accent-dark); border-radius: 999px;
  padding: 0.45rem 0.9rem; font-weight: 700; font-size: 1rem; }

/* Before / after */
.ba { display: grid; gap: 0.8rem; margin-top: 0.8rem; }
.ba .box { border-radius: 10px; padding: 0.8rem 1rem; }
.ba .before { background: var(--accent-soft); border: 1px solid var(--line); }
.ba .after { background: var(--good-bg); border: 1px solid var(--good-line); }
.ba .tag { font-weight: 700; font-size: 0.85rem; text-transform: uppercase; letter-spacing: 0.04em;
  color: var(--soft-ink); margin-bottom: 0.2rem; }

/* Callouts */
.callout { border-radius: 10px; padding: 0.9rem 1.1rem; margin: 1rem 0; }
.callout.warn { background: var(--warn-bg); border: 1px solid var(--warn-line); }
.callout.good { background: var(--good-bg); border: 1px solid var(--good-line); }
.callout strong { display: block; margin-bottom: 0.2rem; font-size: 1.05rem; }

.safe-list, .find-list, .recap { padding-left: 1.2rem; }
.safe-list li, .find-list li, .recap li { margin: 0.5rem 0; }

.weblist { list-style: none; padding: 0; margin: 0.6rem 0; }
.weblist li { margin: 0.5rem 0; font-size: 1.05rem; }
.weblist .name { font-weight: 700; }

/* Conversation transcript */
.convo { margin: 0.6rem 0; }
.bubble { border-radius: 12px; padding: 0.75rem 1rem; margin: 0.5rem 0; }
.bubble .who { font-weight: 700; font-size: 0.8rem; text-transform: uppercase; letter-spacing: 0.04em;
  color: var(--soft-ink); margin-bottom: 0.25rem; }
.bubble.you { background: var(--accent-soft); border: 1px solid #c5dde4; }
.bubble.ai { background: var(--card); border: 1px solid var(--line); }
.bubble.ai .who { color: var(--accent-dark); }
.note { background: var(--note-bg); border-left: 5px solid var(--note-line); border-radius: 0 8px 8px 0;
  padding: 0.55rem 0.9rem; margin: 0.2rem 0 1.1rem; font-size: 0.98rem; }
.note b { color: var(--accent-dark); }

/* Level ladder */
.level { border: 1px solid var(--line); border-radius: 12px; padding: 0.9rem 1rem 1rem; margin: 0.9rem 0; }
.level .label { font-weight: 700; font-size: 1.1rem; margin-bottom: 0.3rem; }
.level .why { color: var(--soft-ink); font-size: 0.98rem; margin: 0.1rem 0 0.6rem; }

/* "How to paste" helper */
details.paste { border: 1px solid var(--line); border-radius: 10px; margin: 1rem 0; background: var(--card); }
details.paste summary { cursor: pointer; padding: 0.7rem 1rem; font-weight: 700; }
details.paste .body { padding: 0 1rem 1rem; }
details.paste ol { padding-left: 1.3rem; }
details.paste li { margin: 0.45rem 0; }

/* Workbook hub grid */
.hub { display: grid; grid-template-columns: 1fr; gap: 0.8rem; margin-top: 1rem; }
.hub a.tile { display: block; border: 1px solid var(--line); border-radius: 12px; padding: 0.9rem 1rem;
  background: var(--card); text-decoration: none; color: var(--ink); }
.hub a.tile:hover { border-color: var(--accent); background: var(--accent-soft); }
.hub .t-emoji { font-size: 1.5rem; }
.hub .t-title { font-weight: 700; font-size: 1.1rem; color: var(--accent-dark); margin: 0.2rem 0; }
.hub .t-desc { color: var(--soft-ink); font-size: 0.98rem; }
@media (min-width: 600px) { .hub { grid-template-columns: 1fr 1fr; } }

/* Cheat sheet */
.cheat { border: 2px dashed var(--accent); }
.cheat ul { padding-left: 1.2rem; }
.printbtn { background: var(--accent); color: #fff; border: none; border-radius: 10px;
  padding: 0.7rem 1.1rem; font-size: 1.05rem; font-weight: 700; cursor: pointer; }

/* Big-button home menu */
.menu { display: grid; grid-template-columns: 1fr; gap: 0.9rem; margin: 1.4rem 0; }
.menu a { display: flex; align-items: center; gap: 1rem; background: var(--card);
  border: 2px solid var(--accent-soft); border-radius: 14px; padding: 1.1rem 1.2rem;
  text-decoration: none; color: var(--ink); }
.menu a:hover { border-color: var(--accent); background: var(--accent-soft); }
.menu a:focus-visible { outline: 3px solid #ffce5c; outline-offset: 2px; }
.menu .m-emoji { font-size: 2rem; flex: 0 0 auto; line-height: 1; }
.menu .m-title { display: block; font-weight: 700; font-size: 1.3rem; color: var(--accent-dark); }
.menu .m-desc { display: block; color: var(--soft-ink); font-size: 1rem; margin-top: 0.15rem; }
@media (min-width: 640px) { .menu { grid-template-columns: 1fr 1fr; } }

.center-btn { text-align: center; margin: 1.4rem 0; }
.bigbtn { display: inline-block; background: var(--accent); color: #fff; text-decoration: none;
  font-weight: 700; font-size: 1.1rem; padding: 0.8rem 1.4rem; border-radius: 12px; }
.bigbtn:hover { background: var(--accent-dark); }
.bigbtn:focus-visible { outline: 3px solid #ffce5c; outline-offset: 2px; }

footer { color: var(--soft-ink); font-size: 0.95rem; text-align: center; margin-top: 2rem; }

/* Desktop sidebar navigation (added by app.js) */
h2 { scroll-margin-top: 72px; }
.sidebar { display: none; }
.side-title { font-weight: 700; color: var(--soft-ink); font-size: 0.8rem; text-transform: uppercase;
  letter-spacing: 0.05em; margin: 1.1rem 0 0.35rem; padding: 0 0.7rem; }
.sidebar a { display: block; padding: 0.45rem 0.7rem; border-radius: 8px; text-decoration: none;
  color: var(--ink); font-size: 0.98rem; line-height: 1.3; margin-bottom: 0.12rem; }
.sidebar a:hover { background: var(--accent-soft); }
.sidebar a.active { background: var(--accent); color: #fff; font-weight: 700; }

/* Collapsible category groups in the sidebar */
.side-group { margin-bottom: 0.15rem; }
.side-group > summary { list-style: none; cursor: pointer; font-weight: 700; color: var(--soft-ink);
  font-size: 0.8rem; text-transform: uppercase; letter-spacing: 0.04em; padding: 0.45rem 0.7rem;
  border-radius: 8px; }
.side-group > summary::-webkit-details-marker { display: none; }
.side-group > summary::after { content: " ▸"; float: right; font-size: 0.9rem; }
.side-group[open] > summary::after { content: " ▾"; }
.side-group > summary:hover { background: var(--accent-soft); }
.side-group a { padding-left: 1.1rem; }
.side-group .active + * , .side-group a.active { /* keep active visible */ }

@media (min-width: 980px) {
  .layout { display: flex; gap: 1.6rem; max-width: 1120px; margin: 0 auto; padding: 0 1rem; align-items: flex-start; }
  .layout .wrap { margin: 0; padding-left: 0; padding-right: 0; flex: 1 1 auto; max-width: 760px; }
  .sidebar { display: block; flex: 0 0 245px; position: sticky; top: 64px;
    max-height: calc(100vh - 80px); overflow-y: auto; padding-bottom: 2rem; }
}

@media print {
  .topbar, .printbtn, .no-print, .sidebar { display: none !important; }
  body { background: #fff; }
  section.card { box-shadow: none; border: 1px solid #999; page-break-inside: avoid; }
}
@media (prefers-reduced-motion: reduce) { * { transition: none !important; } }