:root {
  --font-scale: 1;
  --ink: #183e37;
  --ink-soft: #35564f;
  --paper: #f4f0e7;
  --paper-glow: #e9dfca;
  --card: #fffdf8;
  --card-raised: #ffffff;
  --muted: #586660;
  --line: #d9d3c7;
  --accent: #aa4f35;
  --accent-soft: #f4dfd6;
  --gold: #e5bb55;
  --green: #2f6b5e;
  --green-soft: #e4efea;
  --danger: #a83f32;
  --shadow: 0 12px 34px rgba(29, 52, 44, .09);
  color-scheme: light;
  font-family: -apple-system, BlinkMacSystemFont, "SF Pro Text", "PingFang SC", "Noto Sans SC", sans-serif;
  color: var(--ink);
  background: var(--paper);
  font-size: 17px;
}

html[data-font-size="standard"] { --font-scale: 1; }
html[data-font-size="large"] { --font-scale: 1.13; }
html[data-font-size="xlarge"] { --font-scale: 1.27; }
html[data-theme="dark"] {
  --ink: #e9f1ed;
  --ink-soft: #cbd8d2;
  --paper: #101715;
  --paper-glow: #17231f;
  --card: #18211e;
  --card-raised: #1d2824;
  --muted: #aebdb6;
  --line: #34413c;
  --accent: #e18a69;
  --accent-soft: #3b2822;
  --gold: #e6bd5c;
  --green: #74b39f;
  --green-soft: #203a32;
  --danger: #ed8f7e;
  --shadow: 0 14px 36px rgba(0, 0, 0, .28);
  color-scheme: dark;
}

* { box-sizing: border-box; }
html, body { width: 100%; max-width: 100%; min-height: 100%; overflow-x: hidden; overscroll-behavior-x: none; }
body {
  margin: 0;
  min-height: 100vh;
  background: radial-gradient(circle at 88% -8%, var(--paper-glow) 0, transparent 34%), var(--paper);
  touch-action: pan-y;
  -webkit-text-size-adjust: 100%;
}
button, input { font: inherit; }
button { color: inherit; cursor: pointer; -webkit-tap-highlight-color: transparent; }
button:focus-visible { outline: 3px solid var(--green); outline-offset: 3px; }
svg { display: block; }
.boot { display: grid; place-items: center; min-height: 100vh; color: var(--muted); }

.shell {
  width: 100%;
  max-width: 540px;
  min-height: 100vh;
  margin: 0 auto;
  padding: env(safe-area-inset-top) 18px calc(76px + env(safe-area-inset-bottom));
  position: relative;
  overflow-x: clip;
}
.topbar { display: flex; align-items: center; justify-content: space-between; padding: 14px 0 12px; }
.brand-button, .gear { border: 0; background: transparent; padding: 0; }
.brand { display: block; text-align: left; font: 800 calc(1.42rem * var(--font-scale))/1.05 Georgia, "Songti SC", serif; letter-spacing: -.02em; }
.brand small { display: block; margin-top: 5px; color: var(--muted); font: 650 .62rem/1 -apple-system, BlinkMacSystemFont, sans-serif; letter-spacing: .14em; }
.gear { width: 42px; height: 42px; display: grid; place-items: center; border: 1px solid var(--line); border-radius: 14px; background: color-mix(in srgb, var(--card) 88%, transparent); box-shadow: 0 5px 14px rgba(27, 51, 43, .06); }
.gear svg { width: 23px; height: 23px; fill: none; stroke: currentColor; stroke-width: 1.8; stroke-linecap: round; stroke-linejoin: round; }
.gear.active { background: var(--green-soft); border-color: var(--green); color: var(--green); }

.hero { position: relative; overflow: hidden; padding: 26px; border-radius: 26px; background: var(--ink); color: var(--paper); box-shadow: var(--shadow); }
html[data-theme="dark"] .hero { background: #24473f; color: #fff; }
.hero::after { content: ""; position: absolute; width: 160px; height: 160px; right: -84px; top: -70px; border: 32px solid rgba(255,255,255,.055); border-radius: 50%; pointer-events: none; }
.eyebrow, .chapter-kicker { margin: 0; font-size: calc(.74rem * var(--font-scale)); font-weight: 750; letter-spacing: .1em; text-transform: uppercase; opacity: .76; }
.muted { color: var(--muted); opacity: 1; }
.hero h1 { max-width: 90%; margin: 11px 0 10px; font: 750 calc(1.82rem * var(--font-scale))/1.22 Georgia, "Songti SC", serif; letter-spacing: -.02em; }
.hero p { margin: 0; color: color-mix(in srgb, currentColor 82%, transparent); font-size: calc(.9rem * var(--font-scale)); line-height: 1.68; }
.progress { height: 9px; margin-top: 20px; overflow: hidden; border-radius: 999px; background: rgba(255,255,255,.16); }
.progress i { display: block; height: 100%; border-radius: inherit; background: var(--gold); }
.progress-copy { margin-top: 9px !important; font-size: calc(.76rem * var(--font-scale)) !important; }
.progress.slim { height: 7px; margin: 11px 0 0; background: color-mix(in srgb, var(--line) 65%, transparent); }
.progress.slim i { background: var(--green); }

.screen-title { margin: 12px 0 7px; font: 760 calc(1.82rem * var(--font-scale))/1.18 Georgia, "Songti SC", serif; letter-spacing: -.02em; }
.sub { margin: 0 0 18px; color: var(--muted); font-size: calc(.9rem * var(--font-scale)); line-height: 1.7; }
.section-title { display: flex; align-items: end; justify-content: space-between; gap: 14px; margin: 27px 2px 13px; }
.section-title h2 { margin: 0; font-size: calc(1.06rem * var(--font-scale)); }
.section-title span { flex: 0 0 auto; color: var(--muted); font-size: calc(.72rem * var(--font-scale)); }
.panel { padding: 18px; border: 1px solid var(--line); border-radius: 21px; background: var(--card); box-shadow: 0 6px 18px rgba(28, 51, 43, .045); }
.list { display: grid; gap: 12px; }
.back { min-height: 42px; padding: 8px 0; border: 0; background: transparent; color: var(--ink-soft); font-weight: 700; }
.primary { width: 100%; min-height: 54px; padding: 14px 18px; border: 0; border-radius: 16px; background: var(--accent); color: #fff; font-size: calc(.96rem * var(--font-scale)); font-weight: 760; box-shadow: 0 9px 20px color-mix(in srgb, var(--accent) 25%, transparent); }
.primary:disabled { opacity: .46; cursor: not-allowed; }

.action-grid { display: grid; gap: 12px; }
.action-card { width: 100%; display: flex; align-items: center; gap: 15px; padding: 17px; text-align: left; border: 1px solid var(--line); border-radius: 19px; background: var(--card); box-shadow: 0 6px 18px rgba(28, 51, 43, .045); }
.action-card.primary-action { border-color: color-mix(in srgb, var(--green) 65%, var(--line)); background: var(--green-soft); }
.action-icon, .review-icon, .help-icon { flex: 0 0 auto; width: 42px; height: 42px; display: grid; place-items: center; border-radius: 13px; background: color-mix(in srgb, var(--green) 14%, var(--card)); color: var(--green); }
.action-icon svg, .review-icon svg, .help-icon svg { width: 24px; height: 24px; fill: none; stroke: currentColor; stroke-width: 1.8; stroke-linecap: round; stroke-linejoin: round; }
.action-card strong { display: block; margin-bottom: 4px; font-size: calc(1rem * var(--font-scale)); }
.action-card small { display: block; color: var(--muted); font-size: calc(.75rem * var(--font-scale)); line-height: 1.4; }

.mode-row { display: grid; gap: 10px; }
.choice.mode { width: 100%; display: flex; align-items: center; gap: 12px; padding: 14px; text-align: left; border: 1px solid var(--line); border-radius: 15px; background: transparent; }
.choice.mode.selected { border-color: var(--green); background: var(--green-soft); box-shadow: inset 0 0 0 1px var(--green); }
.choice.mode strong, .choice.mode small { display: block; }
.choice.mode strong { margin-bottom: 3px; font-size: calc(.92rem * var(--font-scale)); }
.choice.mode small { color: var(--muted); font-size: calc(.73rem * var(--font-scale)); }
.badge { display: inline-flex; align-items: center; justify-content: center; min-width: 38px; padding: 5px 8px; border-radius: 9px; font-size: calc(.7rem * var(--font-scale)); font-weight: 850; white-space: nowrap; }
.badge.a { background: #f5d9d0; color: #933e2d; }
.badge.b { background: #f3e7b8; color: #755b16; }
.badge.c { background: #dbe9e3; color: #2d6255; }
html[data-theme="dark"] .badge.a { background: #4b2d26; color: #ffb6a0; }
html[data-theme="dark"] .badge.b { background: #443b21; color: #efd887; }
html[data-theme="dark"] .badge.c { background: #203c33; color: #a4dbc9; }

.source-note { margin: 16px 0 20px; padding: 14px 16px; border-radius: 15px; background: color-mix(in srgb, var(--gold) 21%, var(--card)); color: var(--ink-soft); font-size: calc(.8rem * var(--font-scale)); line-height: 1.62; }
.chapter-card { padding: 18px; border: 1px solid var(--line); border-radius: 22px; background: var(--card); box-shadow: 0 7px 20px rgba(28,51,43,.05); }
.chapter-main { width: 100%; display: grid; grid-template-columns: 48px minmax(0, 1fr); gap: 14px; padding: 0; text-align: left; border: 0; background: transparent; }
.chapter-index { width: 48px; height: 48px; display: grid; place-items: center; border-radius: 14px; background: var(--ink); color: var(--card); font-weight: 800; }
.chapter-main small { color: var(--accent); font-size: calc(.72rem * var(--font-scale)); font-weight: 800; }
.chapter-main h2 { margin: 3px 0 6px; font-size: calc(1.12rem * var(--font-scale)); line-height: 1.35; }
.chapter-main p { margin: 0; color: var(--muted); font-size: calc(.75rem * var(--font-scale)); line-height: 1.52; }
.chapter-progress { display: flex; justify-content: space-between; gap: 10px; margin-top: 16px; color: var(--muted); font-size: calc(.72rem * var(--font-scale)); }
.chapter-progress b { color: var(--ink); font-size: calc(.9rem * var(--font-scale)); }
.chapter-start { width: 100%; min-height: 44px; margin-top: 14px; border: 0; border-radius: 13px; background: var(--green-soft); color: var(--green); font-weight: 780; }
.chapter-kicker { margin-top: 6px; color: var(--accent); opacity: 1; }
.chapter-cta { margin: 8px 0 0; }

.unit { width: 100%; padding: 17px; text-align: left; border: 1px solid var(--line); border-radius: 19px; background: var(--card); box-shadow: 0 5px 15px rgba(28,51,43,.04); }
.unit-head { display: flex; align-items: center; gap: 14px; }
.unit-head > span:last-child { min-width: 0; }
.unit-num { flex: 0 0 auto; width: 41px; height: 41px; display: grid; place-items: center; border-radius: 13px; background: var(--green-soft); color: var(--green); font-weight: 850; }
.unit h3 { margin: 0 0 5px; font-size: calc(.98rem * var(--font-scale)); line-height: 1.4; }
.unit p { margin: 0; color: var(--muted); font-size: calc(.76rem * var(--font-scale)); line-height: 1.55; }
.unit small { display: block; margin-top: 6px; color: var(--muted); font-size: calc(.68rem * var(--font-scale)); }
.knowledge-item h3 { margin-top: 13px; }
.card-top { display: flex; align-items: center; justify-content: space-between; gap: 12px; }
.mastery-label, .mistake-count { color: var(--muted); font-size: calc(.74rem * var(--font-scale)); font-weight: 650; }
.mistake-count { color: var(--danger); }

.scope-tabs { display: flex; gap: 8px; overflow-x: auto; margin: 4px -18px 18px; padding: 2px 18px 6px; scrollbar-width: none; overscroll-behavior-x: contain; }
.scope-tabs::-webkit-scrollbar { display: none; }
.scope-tabs button { flex: 0 0 auto; min-height: 42px; padding: 8px 15px; border: 1px solid var(--line); border-radius: 13px; background: var(--card); color: var(--muted); font-size: calc(.8rem * var(--font-scale)); font-weight: 700; }
.scope-tabs button.on { border-color: var(--green); background: var(--green-soft); color: var(--green); }
.scope-tabs button span { display: inline-grid; place-items: center; min-width: 21px; height: 21px; margin-left: 4px; border-radius: 999px; background: var(--accent-soft); color: var(--accent); font-size: .68rem; }
.empty-state { margin-top: 42px; padding: 30px 20px; text-align: center; color: var(--muted); }
.empty-state > span { width: 58px; height: 58px; display: grid; place-items: center; margin: 0 auto 14px; border-radius: 50%; background: var(--green-soft); color: var(--green); font-size: 1.5rem; font-weight: 800; }
.empty-state h2 { margin: 0 0 8px; color: var(--ink); font-size: calc(1.08rem * var(--font-scale)); }
.empty-state p { margin: 0; font-size: calc(.82rem * var(--font-scale)); }

.review-hero { padding: 26px 22px; text-align: center; border: 1px solid var(--line); border-radius: 24px; background: var(--card); box-shadow: var(--shadow); }
.review-icon { margin: 0 auto 10px; }
.review-hero h2 { margin: 0; font: 760 calc(2.4rem * var(--font-scale))/1 Georgia, serif; }
.review-hero p { margin: 8px 0 19px; color: var(--muted); font-size: calc(.8rem * var(--font-scale)); }
.stats { display: grid; grid-template-columns: repeat(3, minmax(0,1fr)); gap: 9px; }
.review-stats { margin-top: 12px; }
.stat { min-width: 0; padding: 14px 7px; text-align: center; border: 1px solid var(--line); border-radius: 16px; background: var(--card); }
.stat strong { display: block; overflow-wrap: anywhere; font-size: calc(1.25rem * var(--font-scale)); line-height: 1.15; }
.stat span { display: block; margin-top: 5px; color: var(--muted); font-size: calc(.65rem * var(--font-scale)); }

.settings-panel { padding: 0 18px; }
.setting { min-height: 73px; display: flex; align-items: center; justify-content: space-between; gap: 16px; padding: 15px 0; border-bottom: 1px solid var(--line); }
.setting:last-child { border-bottom: 0; }
.setting > span { min-width: 0; }
.setting b, .setting small { display: block; }
.setting b { font-size: calc(.9rem * var(--font-scale)); }
.setting small { margin-top: 4px; color: var(--muted); font-size: calc(.7rem * var(--font-scale)); line-height: 1.4; }
.setting-block { display: block; }
.setting-block .mode-row { width: 100%; }
.segmented { flex: 0 0 auto; display: inline-grid; grid-template-columns: repeat(3, 1fr); gap: 3px; padding: 3px; border-radius: 12px; background: color-mix(in srgb, var(--line) 65%, transparent); }
.segmented button { min-width: 54px; min-height: 38px; padding: 6px 9px; border: 0; border-radius: 9px; background: transparent; color: var(--muted); font-size: calc(.73rem * var(--font-scale)); }
.segmented button.on { background: var(--card-raised); color: var(--ink); font-weight: 800; box-shadow: 0 2px 8px rgba(23,63,56,.12); }
.switch { flex: 0 0 auto; width: 52px; height: 31px; padding: 3px; border: 0; border-radius: 999px; background: color-mix(in srgb, var(--line) 85%, var(--muted)); transition: background .2s ease; }
.switch i { display: block; width: 25px; height: 25px; border-radius: 50%; background: #fff; box-shadow: 0 2px 7px rgba(0,0,0,.22); transition: transform .2s ease; }
.switch.on { background: var(--green); }
.switch.on i { transform: translateX(21px); }
.link-button, .danger-button { flex: 0 0 auto; min-height: 40px; padding: 7px 0 7px 10px; border: 0; background: transparent; color: var(--accent); font-weight: 760; }
.danger-button { color: var(--danger); }

.help-intro { position: relative; overflow: hidden; margin: 18px 0 12px; padding: 22px; border-radius: 23px; background: var(--ink); color: var(--paper); }
html[data-theme="dark"] .help-intro { background: #24473f; color: #fff; }
.help-intro > span { position: absolute; right: 16px; top: 5px; color: rgba(255,255,255,.1); font: 800 4.8rem/1 Georgia, serif; }
.help-intro h2 { position: relative; margin: 0 0 10px; font-size: calc(1.12rem * var(--font-scale)); }
.help-intro p { position: relative; margin: 0; color: color-mix(in srgb, currentColor 82%, transparent); font-size: calc(.84rem * var(--font-scale)); line-height: 1.72; }
.help-grid { display: grid; gap: 12px; }
.help-card { padding: 19px; border: 1px solid var(--line); border-radius: 19px; background: var(--card); }
.help-card h2 { margin: 13px 0 7px; font-size: calc(1rem * var(--font-scale)); }
.help-card p, .help-detail p { margin: 0; color: var(--muted); font-size: calc(.82rem * var(--font-scale)); line-height: 1.72; }
.help-detail { margin-top: 12px; }
.help-detail h2 { margin: 24px 0 9px; font-size: calc(1rem * var(--font-scale)); }
.help-detail h2:first-child { margin-top: 0; }

.study-shell { padding-top: calc(env(safe-area-inset-top) + 8px); }
.session-bar { position: sticky; top: calc(8px + env(safe-area-inset-top)); z-index: 12; display: grid; grid-template-columns: minmax(0,1fr) auto auto; align-items: center; gap: 12px; margin-bottom: 10px; padding: 10px 12px; border: 1px solid color-mix(in srgb, var(--line) 70%, transparent); border-radius: 15px; background: color-mix(in srgb, var(--card) 78%, transparent); box-shadow: 0 8px 24px rgba(23,63,56,.1); backdrop-filter: blur(22px) saturate(160%); -webkit-backdrop-filter: blur(22px) saturate(160%); }
.session-bar > span:first-child { min-width: 0; }
.session-bar small, .session-bar b { display: block; }
.session-bar small { overflow: hidden; color: var(--muted); font-size: calc(.66rem * var(--font-scale)); text-overflow: ellipsis; white-space: nowrap; }
.session-bar b { margin-top: 2px; font-size: calc(.9rem * var(--font-scale)); font-variant-numeric: tabular-nums; }
.session-progress { color: var(--muted); font-size: calc(.68rem * var(--font-scale)); white-space: nowrap; }
.session-bar button { min-height: 36px; padding: 6px 9px; border: 0; border-radius: 10px; background: var(--accent-soft); color: var(--accent); font-size: calc(.72rem * var(--font-scale)); font-weight: 800; }
.end-study { margin-bottom: 7px; }
.study-card { margin-top: 14px; padding: 23px; border: 1px solid var(--line); border-radius: 24px; background: var(--card); box-shadow: var(--shadow); }
.study-card h1 { margin: 10px 0 18px; font: 760 calc(1.55rem * var(--font-scale))/1.35 Georgia, "Songti SC", serif; }
.one-line { padding: 15px 16px; border-left: 4px solid var(--green); border-radius: 4px 15px 15px 4px; background: var(--green-soft); font-size: calc(.94rem * var(--font-scale)); line-height: 1.72; }
.content-block, .source-block { margin-top: 20px; padding-top: 18px; border-top: 1px solid var(--line); }
.content-block h2, .source-block h2 { margin: 0 0 9px; color: var(--accent); font-size: calc(.82rem * var(--font-scale)); letter-spacing: .08em; }
.content-block p, .source-block p { margin: 0; font-size: calc(.94rem * var(--font-scale)); line-height: 1.82; }
.memory { margin-left: -4px; margin-right: -4px; padding: 17px 16px; border: 0; border-radius: 16px; background: color-mix(in srgb, var(--gold) 22%, var(--card)); }
.source-block p { margin-top: 5px; color: var(--muted); font-size: calc(.78rem * var(--font-scale)); }
.sticky-action { margin-top: 16px; }
.question h1 { margin: 14px 0 20px; font-size: calc(1.25rem * var(--font-scale)); line-height: 1.58; }
.question-meta { display: flex; align-items: center; justify-content: space-between; gap: 12px; }
.question-meta small { max-width: 62%; color: var(--muted); font-size: calc(.68rem * var(--font-scale)); text-align: right; line-height: 1.4; }
.option { width: 100%; display: grid; grid-template-columns: 34px minmax(0,1fr); align-items: center; gap: 10px; min-height: 56px; margin: 8px 0; padding: 11px 14px; text-align: left; border: 1px solid var(--line); border-radius: 15px; background: var(--card); font-size: calc(.9rem * var(--font-scale)); line-height: 1.5; }
.option > span { width: 31px; height: 31px; display: grid; place-items: center; border-radius: 10px; background: var(--green-soft); color: var(--green); font-weight: 800; }
.option.chosen { border-color: var(--green); background: var(--green-soft); }
.option.correct { border-color: #368368; background: color-mix(in srgb, #69b795 22%, var(--card)); }
.option.wrong { border-color: var(--danger); background: color-mix(in srgb, var(--danger) 14%, var(--card)); }
.feedback { margin-top: 18px; padding: 17px; border-radius: 16px; background: var(--green-soft); font-size: calc(.9rem * var(--font-scale)); line-height: 1.65; }
.feedback p { margin: 7px 0 0; }
.feedback.partial { background: color-mix(in srgb, var(--gold) 24%, var(--card)); }
.feedback.incorrect { background: color-mix(in srgb, var(--danger) 13%, var(--card)); }
.answer-label { display: block; margin: 0 0 8px; font-size: calc(.9rem * var(--font-scale)); font-weight: 800; }
.answer-editor { width: 100%; min-height: 180px; resize: vertical; padding: 15px; color: var(--text); border: 1px solid var(--line); border-radius: 16px; outline: none; background: var(--card); font: inherit; font-size: calc(.9rem * var(--font-scale)); line-height: 1.7; }
.answer-editor:focus { border-color: var(--green); box-shadow: 0 0 0 3px color-mix(in srgb, var(--green) 13%, transparent); }
.answer-tip { margin: 9px 2px 0; color: var(--muted); font-size: calc(.75rem * var(--font-scale)); line-height: 1.55; }
.user-answer, .reference-answer, .self-assessment { margin-top: 14px; padding: 16px; border: 1px solid var(--line); border-radius: 16px; background: var(--card); }
.reference-answer { border-color: color-mix(in srgb, var(--gold) 60%, var(--line)); background: color-mix(in srgb, var(--gold) 14%, var(--card)); }
.user-answer h2, .reference-answer h2, .self-assessment h2 { margin: 0 0 8px; font-size: calc(.94rem * var(--font-scale)); }
.user-answer p, .reference-answer p, .self-assessment > p { margin: 0; white-space: pre-wrap; font-size: calc(.86rem * var(--font-scale)); line-height: 1.7; }
.self-assessment > p { margin-bottom: 12px; color: var(--muted); }
.self-point { width: 100%; display: grid; grid-template-columns: 30px minmax(0,1fr); align-items: center; gap: 10px; margin: 8px 0; padding: 11px 12px; color: var(--text); text-align: left; border: 1px solid var(--line); border-radius: 13px; background: var(--bg); font-size: calc(.82rem * var(--font-scale)); line-height: 1.5; }
.self-point span { width: 27px; height: 27px; display: grid; place-items: center; border: 1px solid var(--line); border-radius: 8px; background: var(--card); color: white; font-weight: 850; }
.self-point.chosen { border-color: var(--green); background: var(--green-soft); }
.self-point.chosen span { border-color: var(--green); background: var(--green); }
.self-point:disabled { opacity: 1; }

.summary-screen { display: flex; flex-direction: column; justify-content: center; padding-top: 40px; text-align: center; }
.summary-mark { width: 82px; height: 82px; display: grid; place-items: center; margin: 0 auto 20px; border-radius: 50%; background: var(--green-soft); color: var(--green); font-size: 2rem; font-weight: 850; }
.summary-screen .stats { margin: 24px 0; text-align: initial; }
.summary-screen .primary { margin-top: 4px; }

.nav { position: fixed; z-index: 30; left: 50%; bottom: calc(6px + env(safe-area-inset-bottom)); transform: translateX(-50%); width: min(500px, calc(100% - 20px)); display: grid; grid-template-columns: repeat(4,1fr); gap: 3px; padding: 4px 7px; border: 1px solid color-mix(in srgb, #fff 48%, var(--line)); border-radius: 19px; background: color-mix(in srgb, var(--card) 65%, transparent); box-shadow: 0 10px 28px rgba(23,63,56,.15), inset 0 1px 0 rgba(255,255,255,.45); backdrop-filter: blur(24px) saturate(165%); -webkit-backdrop-filter: blur(24px) saturate(165%); }
.nav button { min-width: 0; min-height: 48px; display: flex; flex-direction: column; align-items: center; justify-content: center; gap: 1px; padding: 3px 2px; border: 0; border-radius: 13px; background: transparent; color: var(--muted); font-size: calc(.69rem * var(--font-scale)); font-weight: 720; line-height: 1.05; }
.nav button.active { background: color-mix(in srgb, var(--green-soft) 80%, transparent); color: var(--green); }
.nav-icon { width: 25px; height: 25px; display: grid; place-items: center; }
.nav-icon svg { width: 24px; height: 24px; fill: none; stroke: currentColor; stroke-width: 1.9; stroke-linecap: round; stroke-linejoin: round; }

@media (min-width: 700px) { .shell { border-left: 1px solid var(--line); border-right: 1px solid var(--line); } }
@media (max-width: 380px) {
  .shell { padding-left: 14px; padding-right: 14px; }
  .scope-tabs { margin-left: -14px; margin-right: -14px; padding-left: 14px; padding-right: 14px; }
  .hero { padding: 22px; }
  .session-bar { gap: 7px; }
  .session-progress { display: none; }
  .segmented button { min-width: 46px; padding-inline: 6px; }
  .font-setting { align-items: flex-start; flex-direction: column; }
}
@media (prefers-reduced-motion: reduce) { *, *::before, *::after { scroll-behavior: auto !important; transition: none !important; } }