:root {
  --ink: #243447;
  --ink-soft: #526477;
  --paper: #fbfaf6;
  --paper-deep: #f2ebdd;
  --line: #d8d1c4;
  --line-strong: #b8afa0;
  --red: #b64b3d;
  --red-deep: #8e342d;
  --green: #2d755b;
  --green-wash: #e7f1ea;
  --blue-wash: #e9eff4;
  --yellow-wash: #f5edcf;
  --shadow: 0 12px 40px rgba(36, 52, 71, 0.09);
  --radius: 18px;
  --font: 'Noto Sans TC', 'PingFang TC', 'Microsoft JhengHei', system-ui, sans-serif;
}

* { box-sizing: border-box; }
html { background: #e7e3da; scroll-behavior: smooth; }
body { margin: 0; min-width: 320px; color: var(--ink); background: var(--paper); font-family: var(--font); line-height: 1.6; }
button, input, select { font: inherit; }
button, a { -webkit-tap-highlight-color: transparent; }
a { color: inherit; text-decoration: none; }
button { border: 0; cursor: pointer; }
button:disabled { cursor: not-allowed; opacity: .48; }

.paper-grain { position: fixed; inset: 0; pointer-events: none; opacity: .22; z-index: 0; background-image: radial-gradient(rgba(36,52,71,.05) .55px, transparent .55px); background-size: 5px 5px; }
.site-header, .app-shell, .site-footer { position: relative; z-index: 1; }
.site-header { max-width: 1240px; margin: 0 auto; min-height: 82px; padding: 18px 32px; display: flex; align-items: center; gap: 32px; border-bottom: 1px solid var(--line); }
.brand { display: flex; align-items: center; gap: 12px; min-width: 260px; }
.brand-mark { width: 45px; height: 45px; background: var(--ink); color: var(--paper-deep); border-radius: 11px; display: grid; place-items: center; position: relative; font-weight: 900; letter-spacing: -.06em; font-size: 13px; }
.brand-mark:after { content: ''; position: absolute; left: 9px; right: 9px; bottom: 8px; height: 2px; background: var(--red); }
.brand-mark i { position: absolute; width: 2px; height: 10px; right: 11px; top: 11px; background: var(--paper-deep); transform: rotate(26deg); }
.brand-copy { display: grid; line-height: 1.2; }
.brand-copy strong { font-size: 15px; letter-spacing: .1em; }
.brand-copy small { margin-top: 5px; color: var(--ink-soft); font-size: 9px; letter-spacing: .08em; }
.top-nav { display: flex; align-items: center; gap: 26px; margin-left: auto; color: var(--ink-soft); font-size: 13px; font-weight: 600; }
.top-nav a { padding: 7px 0; border-bottom: 1px solid transparent; transition: color .16s ease, border .16s ease; }
.top-nav a:hover { color: var(--ink); border-color: var(--red); }
.nav-count { display: inline-grid; place-items: center; min-width: 19px; height: 19px; margin-left: 3px; padding: 0 5px; border-radius: 99px; color: var(--paper); background: var(--red); font-size: 10px; }
.local-badge { display: inline-flex; align-items: center; gap: 7px; padding: 5px 10px; border: 1px solid var(--line); border-radius: 99px; color: var(--ink-soft); font-size: 11px; white-space: nowrap; }
.status-dot { width: 7px; height: 7px; border-radius: 50%; background: var(--green); box-shadow: 0 0 0 3px rgba(45,117,91,.12); }

.app-shell { max-width: 1240px; min-height: calc(100vh - 140px); margin: 0 auto; padding: 0 32px 64px; }
.site-footer { max-width: 1176px; margin: 0 auto; padding: 18px 32px 30px; display: flex; justify-content: space-between; color: #8b867d; font-size: 11px; border-top: 1px solid var(--line); }

.eyebrow { margin: 0; color: var(--red); font-size: 11px; font-weight: 800; letter-spacing: .2em; text-transform: uppercase; }
.page-title { margin: 8px 0 0; font-size: clamp(30px, 4vw, 54px); line-height: 1.13; letter-spacing: -.045em; font-weight: 900; }
.page-subtitle { max-width: 590px; margin: 14px 0 0; color: var(--ink-soft); font-size: 16px; line-height: 1.8; }
.section-label { display: flex; align-items: center; gap: 12px; margin: 0 0 14px; color: var(--ink-soft); font-size: 11px; letter-spacing: .16em; font-weight: 800; text-transform: uppercase; }
.section-label:after { content: ''; height: 1px; flex: 1; background: var(--line); }

.home-hero { padding: 62px 0 30px; display: grid; grid-template-columns: 1.08fr .92fr; gap: 60px; align-items: end; }
.hero-rule { display: flex; align-items: center; gap: 12px; margin-top: 29px; color: var(--ink-soft); font-size: 12px; }
.hero-rule:before { content: ''; width: 48px; height: 3px; background: var(--red); }
.stats-strip { display: grid; grid-template-columns: repeat(3, 1fr); border-top: 1px solid var(--line); border-bottom: 1px solid var(--line); }
.stat { padding: 18px 18px 18px 0; }
.stat + .stat { padding-left: 18px; border-left: 1px solid var(--line); }
.stat strong { display: block; font-size: 25px; letter-spacing: -.03em; }
.stat span { color: var(--ink-soft); font-size: 11px; }

.paper-preview { position: relative; min-height: 245px; padding: 26px 29px; background: var(--paper-deep); border: 1px solid var(--line-strong); box-shadow: 12px 12px 0 rgba(182,75,61,.13); transform: rotate(1.5deg); }
.paper-preview:before, .paper-preview:after { content: ''; position: absolute; width: 10px; height: 10px; border: 1px solid var(--line-strong); border-radius: 50%; background: var(--paper); }
.paper-preview:before { top: 16px; right: 17px; }
.paper-preview:after { bottom: 17px; left: 17px; }
.paper-preview .mini-code { color: var(--red); font: 800 10px/1.2 monospace; letter-spacing: .14em; }
.paper-preview h2 { margin: 32px 0 6px; font-size: 25px; letter-spacing: -.04em; }
.paper-preview p { margin: 0; max-width: 300px; color: var(--ink-soft); font-size: 13px; }
.paper-preview .preview-meta { display: flex; gap: 24px; margin-top: 29px; padding-top: 13px; border-top: 1px solid var(--line-strong); color: var(--ink); font-size: 11px; font-weight: 700; }

.home-section { margin-top: 38px; }
.mode-grid { display: grid; grid-template-columns: 1.2fr 1fr 1fr; gap: 14px; }
.mode-card { min-height: 236px; padding: 24px; display: flex; flex-direction: column; border: 1px solid var(--line); background: rgba(255,255,255,.52); transition: transform .16s ease, box-shadow .16s ease, border .16s ease; }
.mode-card:hover { transform: translateY(-3px); box-shadow: var(--shadow); border-color: var(--line-strong); }
.mode-card.featured { background: var(--ink); color: var(--paper); border-color: var(--ink); }
.mode-card .card-index { color: var(--red); font: 800 11px/1 monospace; letter-spacing: .1em; }
.mode-card.featured .card-index { color: #efaa9e; }
.mode-card h3 { margin: 23px 0 5px; font-size: 20px; letter-spacing: -.03em; }
.mode-card p { margin: 0; color: var(--ink-soft); font-size: 13px; line-height: 1.75; }
.mode-card.featured p { color: #c6d0d9; }
.card-action { display: flex; align-items: center; justify-content: space-between; margin-top: auto; padding-top: 21px; color: var(--red); font-size: 12px; font-weight: 800; }
.featured .card-action { color: #f1b3aa; }
.arrow { font-size: 20px; line-height: 1; }

.resume-banner { display: flex; align-items: center; gap: 18px; margin-top: 16px; padding: 16px 20px; background: var(--yellow-wash); border-left: 4px solid #c19b39; }
.resume-banner > div { flex: 1; }
.resume-banner strong { display: block; font-size: 14px; }
.resume-banner span { display: block; color: var(--ink-soft); font-size: 12px; }
.inline-btn { padding: 9px 15px; background: var(--ink); color: var(--paper); font-size: 12px; font-weight: 800; }
.inline-btn.ghost { background: transparent; color: var(--ink); border: 1px solid var(--line-strong); }

.builder { padding: 24px; border: 1px solid var(--line); background: rgba(255,255,255,.5); }
.builder-grid { display: grid; grid-template-columns: 1fr 1.25fr 1fr 1.1fr auto; gap: 12px; align-items: end; }
.field { display: grid; gap: 6px; }
.field label { color: var(--ink-soft); font-size: 11px; font-weight: 800; letter-spacing: .04em; }
.field select { width: 100%; height: 42px; padding: 0 12px; color: var(--ink); background: var(--paper); border: 1px solid var(--line-strong); border-radius: 0; outline: 0; }
.field select:focus { border-color: var(--red); box-shadow: 0 0 0 3px rgba(182,75,61,.12); }
.input-like { display: flex; align-items: center; height: 42px; padding: 0 12px; color: var(--ink-soft); background: #ebe7de; border: 1px solid var(--line); font-size: 12px; }
.primary-btn, .secondary-btn, .danger-btn { display: inline-flex; align-items: center; justify-content: center; gap: 9px; min-height: 43px; padding: 0 18px; font-size: 12px; font-weight: 800; transition: transform .16s ease, box-shadow .16s ease, background .16s ease; }
.primary-btn { color: var(--paper); background: var(--red); box-shadow: 4px 4px 0 rgba(142,52,45,.16); }
.primary-btn:hover, .secondary-btn:hover, .danger-btn:hover { transform: translateY(-2px); }
.secondary-btn { color: var(--ink); background: transparent; border: 1px solid var(--line-strong); }
.danger-btn { color: var(--red-deep); background: #f9e8e5; border: 1px solid #e6bbb5; }

.recent-list { display: grid; gap: 0; border-top: 1px solid var(--line); }
.recent-row { display: grid; grid-template-columns: 1fr auto auto; gap: 26px; align-items: center; padding: 14px 0; border-bottom: 1px solid var(--line); }
.recent-row strong { display: block; font-size: 13px; }
.recent-row span { color: var(--ink-soft); font-size: 11px; }
.recent-score { font-size: 20px; font-weight: 900; }
.recent-score.good { color: var(--green); }
.recent-score.low { color: var(--red); }

.practice-shell { display: grid; grid-template-columns: 235px minmax(0, 1fr); gap: 28px; padding-top: 30px; }
.practice-sidebar { position: sticky; top: 16px; align-self: start; padding: 20px 18px; border: 1px solid var(--line); background: rgba(255,255,255,.58); }
.side-kicker { color: var(--red); font: 800 10px/1.3 monospace; letter-spacing: .12em; }
.practice-sidebar h1 { margin: 10px 0 3px; font-size: 19px; line-height: 1.35; }
.side-meta { color: var(--ink-soft); font-size: 11px; }
.timer-box { margin: 20px 0; padding: 13px; background: var(--ink); color: var(--paper); }
.timer-box small { display: block; color: #afbecb; font-size: 10px; }
.timer-box strong { display: block; margin-top: 3px; font: 900 28px/1.2 monospace; letter-spacing: .05em; }
.timer-box.is-urgent { background: var(--red-deep); }
.progress-label { display: flex; justify-content: space-between; color: var(--ink-soft); font-size: 10px; }
.progress-track { height: 5px; margin-top: 7px; background: #e1ddd3; overflow: hidden; }
.progress-fill { height: 100%; background: var(--red); transition: width .25s ease; }
.question-map { display: grid; grid-template-columns: repeat(5, 1fr); gap: 6px; margin-top: 20px; }
.map-btn { aspect-ratio: 1; padding: 0; color: var(--ink-soft); background: var(--paper); border: 1px solid var(--line); font-size: 11px; }
.map-btn.is-current { color: var(--paper); background: var(--ink); border-color: var(--ink); }
.map-btn.is-answered { color: var(--green); border-color: #8bb29d; box-shadow: inset 0 -3px 0 var(--green); }
.map-btn.is-marked { position: relative; }
.map-btn.is-marked:after { content: ''; position: absolute; top: 3px; right: 3px; width: 4px; height: 4px; border-radius: 50%; background: var(--red); }
.side-legend { display: grid; gap: 6px; margin-top: 18px; color: var(--ink-soft); font-size: 10px; }
.side-legend span { display: flex; align-items: center; gap: 7px; }
.legend-dot { width: 9px; height: 9px; display: inline-block; border: 1px solid var(--line-strong); }
.legend-dot.done { border-color: #8bb29d; background: var(--green-wash); }
.legend-dot.mark { border-radius: 50%; background: var(--red); border: 0; }

.question-column { min-width: 0; }
.practice-topbar { display: flex; justify-content: space-between; align-items: center; margin-bottom: 14px; color: var(--ink-soft); font-size: 12px; }
.practice-topbar strong { color: var(--ink); font-size: 14px; }
.question-paper { padding: clamp(23px, 4vw, 43px); border: 1px solid var(--line-strong); background: var(--paper); box-shadow: var(--shadow); }
.question-paper-head { display: flex; justify-content: space-between; align-items: start; gap: 20px; padding-bottom: 17px; border-bottom: 1px solid var(--line); }
.question-number { display: flex; align-items: center; gap: 11px; color: var(--red); font-size: 12px; font-weight: 800; }
.number-badge { display: inline-grid; place-items: center; width: 35px; height: 35px; border-radius: 50%; color: var(--paper); background: var(--red); font-size: 15px; }
.question-topic { padding: 5px 9px; color: var(--ink-soft); border: 1px solid var(--line); font-size: 10px; white-space: nowrap; }
.question-stem { margin: 25px 0 19px; color: var(--ink); font-size: clamp(17px, 2vw, 21px); font-weight: 600; line-height: 1.8; letter-spacing: .005em; }
.question-image { display: block; max-width: min(100%, 500px); max-height: 320px; margin: 11px auto 27px; object-fit: contain; border: 1px solid var(--line); background: #fff; }
.generated-diagram { width: min(100%, 640px); max-width: 100%; height: auto; max-height: none; }
.diagram-card { width: min(100%, 560px); margin: 11px auto 27px; padding: 12px 16px; border: 1px solid var(--line); background: #fff; }
.diagram-card svg { display: block; width: 100%; height: auto; }
.diagram-card text { fill: var(--ink); font-family: var(--font); font-size: 13px; }
.diagram-card .axis { fill: none; stroke: var(--ink); stroke-width: 2; }
.diagram-card .tick { fill: none; stroke: var(--line-strong); stroke-width: 1.5; }
.diagram-card .curve, .diagram-card .line { fill: none; stroke: var(--red); stroke-width: 3; }
.diagram-card .shape { fill: rgba(182,75,61,.1); stroke: var(--ink); stroke-width: 2.5; }
.diagram-card .helper { fill: none; stroke: var(--ink-soft); stroke-width: 1.6; stroke-dasharray: 6 5; }
.diagram-card .point { fill: var(--red); stroke: #fff; stroke-width: 2; }
.diagram-card .point.second { fill: var(--green); }
.diagram-card .bar { fill: rgba(36,52,71,.78); stroke: var(--ink); stroke-width: 1; }
.image-note { margin: -18px auto 20px; color: var(--ink-soft); text-align: center; font-size: 10px; }
.source-figure { width: min(100%, 560px); margin: -10px auto 20px; padding: 9px 12px; border: 1px dashed var(--line-strong); background: var(--paper-deep); color: var(--ink-soft); font-size: 12px; }
.source-figure summary { cursor: pointer; font-weight: 700; color: var(--red); }
.source-figure .solution-image { margin: 14px auto 3px; }
.options { display: grid; gap: 10px; }
.option-btn { display: grid; grid-template-columns: 36px minmax(0,1fr) auto; align-items: center; gap: 12px; width: 100%; padding: 13px 15px; color: var(--ink); background: #fff; border: 1px solid var(--line); text-align: left; transition: border .16s ease, background .16s ease, transform .16s ease; }
.option-btn:hover { border-color: var(--ink-soft); transform: translateX(2px); }
.option-btn.selected { color: var(--ink); background: var(--blue-wash); border-color: #7891a8; box-shadow: inset 4px 0 0 var(--ink); }
.option-letter { display: inline-grid; place-items: center; width: 28px; height: 28px; border: 1px solid var(--line-strong); border-radius: 50%; color: var(--ink-soft); font: 800 12px/1 monospace; }
.selected .option-letter { color: var(--paper); background: var(--ink); border-color: var(--ink); }
.option-text { min-width: 0; font-size: 15px; line-height: 1.55; }
.option-check { color: var(--green); font-weight: 900; }
.mark-button { display: inline-flex; align-items: center; gap: 6px; margin-top: 19px; padding: 5px 0; color: var(--ink-soft); background: transparent; border-bottom: 1px dashed var(--line-strong); font-size: 11px; }
.mark-button.is-marked { color: var(--red); border-color: var(--red); }
.practice-controls { display: flex; align-items: center; justify-content: space-between; gap: 10px; margin-top: 17px; }
.practice-controls .control-group { display: flex; gap: 9px; }

.result-shell { padding-top: 52px; }
.result-heading { display: flex; align-items: end; justify-content: space-between; gap: 30px; padding-bottom: 25px; border-bottom: 1px solid var(--line-strong); }
.score-block { display: flex; align-items: end; gap: 16px; }
.score-number { font-size: 68px; font-weight: 900; letter-spacing: -.08em; line-height: .9; }
.score-denom { padding-bottom: 5px; color: var(--ink-soft); font-size: 13px; }
.score-stamp { padding: 9px 13px; color: var(--green); background: var(--green-wash); border: 1px solid #acd0b9; font-size: 12px; font-weight: 800; }
.result-stats { display: flex; gap: 18px; text-align: right; }
.result-stats div { display: grid; gap: 2px; }
.result-stats strong { font-size: 22px; }
.result-stats span { color: var(--ink-soft); font-size: 10px; }
.result-toolbar { display: flex; align-items: center; justify-content: space-between; gap: 15px; margin: 27px 0 14px; }
.filter-tabs { display: flex; flex-wrap: wrap; gap: 6px; }
.filter-tab { padding: 8px 12px; color: var(--ink-soft); background: transparent; border: 1px solid var(--line); font-size: 11px; font-weight: 700; }
.filter-tab.active { color: var(--paper); background: var(--ink); border-color: var(--ink); }
.review-list { display: grid; gap: 14px; }
.review-card { border: 1px solid var(--line); background: rgba(255,255,255,.62); }
.review-card.correct { border-left: 4px solid var(--green); }
.review-card.wrong { border-left: 4px solid var(--red); }
.review-card.unanswered { border-left: 4px solid #c19b39; }
.review-head { display: flex; align-items: center; justify-content: space-between; gap: 14px; padding: 15px 18px; border-bottom: 1px solid var(--line); }
.review-head-left { display: flex; align-items: center; gap: 11px; }
.review-head-left strong { font-size: 14px; }
.review-head-left span { color: var(--ink-soft); font-size: 11px; }
.review-status { padding: 4px 8px; font-size: 10px; font-weight: 800; }
.review-status.correct { color: var(--green); background: var(--green-wash); }
.review-status.wrong { color: var(--red-deep); background: #f9e8e5; }
.review-status.unanswered { color: #876c1a; background: var(--yellow-wash); }
.review-body { padding: 18px 22px 22px; }
.review-stem { margin: 0 0 15px; font-weight: 600; line-height: 1.75; }
.review-options { display: grid; grid-template-columns: repeat(2, 1fr); gap: 7px; }
.review-option { padding: 9px 11px; color: var(--ink-soft); background: #fff; border: 1px solid var(--line); font-size: 12px; line-height: 1.5; }
.review-option.right { color: var(--green); background: var(--green-wash); border-color: #9fc5ae; font-weight: 700; }
.review-option.user-wrong { color: var(--red-deep); background: #f9e8e5; border-color: #dfaca5; }
.solution { margin-top: 18px; border-top: 1px solid var(--line); }
.solution summary { padding: 14px 0 8px; color: var(--ink); cursor: pointer; font-size: 13px; font-weight: 800; list-style: none; }
.solution summary::-webkit-details-marker { display: none; }
.solution summary:before { content: '+'; display: inline-grid; place-items: center; width: 20px; height: 20px; margin-right: 8px; color: var(--paper); background: var(--red); font-weight: 400; }
.solution[open] summary:before { content: '−'; }
.solution-image { display: block; max-width: min(100%, 390px); max-height: 240px; margin: 6px 0 17px; object-fit: contain; border: 1px solid var(--line); background: #fff; }
.step-list { display: grid; gap: 9px; counter-reset: step; }
.step { display: grid; grid-template-columns: 28px 1fr; gap: 10px; align-items: start; padding: 10px 12px; background: #fff; border-left: 2px solid var(--line-strong); }
.step:before { counter-increment: step; content: counter(step); display: grid; place-items: center; width: 24px; height: 24px; color: var(--paper); background: var(--ink); border-radius: 50%; font: 800 11px/1 monospace; }
.step strong { display: block; margin-bottom: 2px; font-size: 11px; color: var(--red); }
.step p { margin: 0; color: var(--ink-soft); font-size: 13px; line-height: 1.7; }
.working-box { margin-top: 10px; padding: 13px 15px; color: var(--ink); background: var(--paper-deep); border: 1px dashed var(--line-strong); font-family: Georgia, 'Times New Roman', serif; font-size: 15px; line-height: 1.7; white-space: pre-wrap; }
.gallery-shell { padding-top: 52px; }
.gallery-note { display: flex; align-items: baseline; gap: 14px; margin: 24px 0 18px; padding: 14px 17px; color: var(--ink-soft); background: var(--yellow-wash); border-left: 3px solid #c19b39; font-size: 12px; line-height: 1.7; }
.gallery-note strong { color: var(--ink); white-space: nowrap; }
.gallery-list { display: grid; gap: 18px; }
.gallery-card { padding: 20px 22px 22px; border: 1px solid var(--line); background: rgba(255,255,255,.72); scroll-margin-top: 80px; }
.gallery-card-head { display: flex; align-items: center; justify-content: space-between; gap: 12px; padding-bottom: 10px; border-bottom: 1px solid var(--line); color: var(--red); font-size: 11px; letter-spacing: .08em; }
.gallery-card-head span { color: var(--ink-soft); letter-spacing: 0; }
.gallery-card h2 { max-width: 900px; margin: 15px 0 17px; font-size: 17px; line-height: 1.65; }
.gallery-image { display: block; width: min(100%, 720px); margin: 0 auto; border: 1px solid var(--line); background: #fff; }
.gallery-caption { margin: 8px 0 0; color: var(--ink-soft); text-align: center; font-size: 10px; }
.gallery-card .source-figure { margin: 15px auto 0; }

.empty-state { padding: 54px 28px; text-align: center; border: 1px dashed var(--line-strong); background: rgba(255,255,255,.42); }
.empty-state strong { display: block; font-size: 18px; }
.empty-state p { max-width: 410px; margin: 8px auto 20px; color: var(--ink-soft); font-size: 13px; }
.help-shell { max-width: 850px; padding: 57px 0; }
.help-grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: 14px; margin-top: 27px; }
.help-card { padding: 21px; border: 1px solid var(--line); background: rgba(255,255,255,.5); }
.help-card h3 { margin: 0 0 7px; font-size: 16px; }
.help-card p { margin: 0; color: var(--ink-soft); font-size: 13px; line-height: 1.8; }
.notice { margin-top: 18px; padding: 14px 16px; color: var(--ink-soft); background: var(--yellow-wash); border-left: 3px solid #c19b39; font-size: 12px; }
.modal-backdrop { position: fixed; inset: 0; z-index: 20; display: grid; place-items: center; padding: 20px; background: rgba(36,52,71,.38); }
.confirm-dialog { width: min(100%, 460px); padding: 27px; background: var(--paper); border: 1px solid var(--line-strong); box-shadow: 12px 12px 0 rgba(182,75,61,.2); }
.confirm-dialog h2 { margin: 8px 0 8px; font-size: 25px; letter-spacing: -.04em; }
.confirm-dialog p { margin: 0; color: var(--ink-soft); font-size: 13px; line-height: 1.8; }
.confirm-actions { display: flex; justify-content: flex-end; gap: 9px; margin-top: 24px; }

@media (max-width: 900px) {
  .site-header { padding: 15px 20px; gap: 15px; }
  .brand { min-width: 0; }
  .brand-copy small { display: none; }
  .top-nav { gap: 14px; font-size: 12px; }
  .local-badge { display: none; }
  .app-shell { padding: 0 20px 48px; }
  .home-hero { grid-template-columns: 1fr; gap: 34px; padding-top: 46px; }
  .paper-preview { max-width: 550px; }
  .mode-grid { grid-template-columns: 1fr 1fr; }
  .mode-card.featured { grid-column: span 2; }
  .builder-grid { grid-template-columns: 1fr 1fr; }
  .builder-grid .primary-btn { width: 100%; }
  .practice-shell { grid-template-columns: 1fr; }
  .practice-sidebar { position: static; padding: 15px; }
  .practice-sidebar h1 { display: inline; margin-right: 10px; }
  .timer-box { display: inline-block; min-width: 140px; margin: 0 0 0 12px; vertical-align: middle; }
  .question-map { grid-template-columns: repeat(10, 1fr); }
  .side-legend { display: none; }
}

@media (max-width: 600px) {
  .site-header { flex-wrap: wrap; min-height: 0; }
  .top-nav { order: 3; width: 100%; justify-content: space-between; border-top: 1px solid var(--line); padding-top: 10px; }
  .app-shell { padding: 0 14px 40px; }
  .site-footer { padding: 16px 14px 25px; display: grid; gap: 5px; }
  .page-title { font-size: 35px; }
  .page-subtitle { font-size: 14px; }
  .stats-strip { grid-template-columns: repeat(3, 1fr); }
  .stat { padding: 13px 8px 13px 0; }
  .stat + .stat { padding-left: 8px; }
  .stat strong { font-size: 18px; }
  .stat span { font-size: 9px; }
  .mode-grid { grid-template-columns: 1fr; }
  .mode-card.featured { grid-column: auto; }
  .mode-card { min-height: 190px; }
  .builder { padding: 16px; }
  .builder-grid { grid-template-columns: 1fr; }
  .resume-banner { align-items: start; flex-wrap: wrap; }
  .resume-banner .inline-btn { margin-left: 0; }
  .practice-shell { padding-top: 18px; }
  .practice-sidebar { margin: 0 -1px; }
  .timer-box { float: right; margin-top: -5px; }
  .question-map { clear: both; padding-top: 16px; grid-template-columns: repeat(9, 1fr); }
  .question-paper { padding: 20px 16px; }
  .question-paper-head { align-items: center; }
  .question-topic { max-width: 110px; overflow: hidden; text-overflow: ellipsis; }
  .question-stem { font-size: 17px; }
  .option-btn { grid-template-columns: 31px minmax(0,1fr) auto; padding: 11px 10px; gap: 9px; }
  .option-text { font-size: 14px; }
  .practice-controls { align-items: stretch; flex-direction: column-reverse; }
  .practice-controls .control-group { width: 100%; }
  .practice-controls .control-group > * { flex: 1; }
  .practice-controls > .secondary-btn { width: 100%; }
  .result-heading { align-items: start; flex-direction: column; gap: 20px; }
  .result-stats { width: 100%; justify-content: space-between; text-align: left; }
  .score-number { font-size: 56px; }
  .result-toolbar { align-items: start; flex-direction: column; }
  .review-options { grid-template-columns: 1fr; }
  .review-body { padding: 15px; }
  .help-grid { grid-template-columns: 1fr; }
  .gallery-shell { padding-top: 35px; }
  .gallery-card { padding: 15px; }
  .gallery-card h2 { font-size: 15px; }
  .gallery-note { display: block; }
  .gallery-note strong { display: block; margin-bottom: 4px; }
  .confirm-actions { flex-direction: column-reverse; }
  .confirm-actions > * { width: 100%; }
}

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