/* QuestiBooks — 스타일
   Layout: 1180px 컨테이너의 제품형 사이트. 차가운 회색 바탕 위 흰 카드, 파란색 하나만 액센트로 쓰고 색은 파스텔 표지가 담당한다. */
:root {
  --bg: #f4f7fb; --surface: #ffffff; --surface-2: #eef3fb; --surface-3: #e6edf8;
  --fg: #172033; --fg-2: #3b4658; --muted: #6b7788; --line: #e1e7f0; --line-2: #c9d3e0;
  --accent: #2f6fed; --accent-2: #1d4ed8; --accent-soft: #e8f0ff; --accent-soft-2: #d6e4ff; --on-accent: #ffffff;
  --ok: #15803d; --ok-soft: #dcfce7; --warn: #b45309; --warn-soft: #fef3c7; --bad: #dc2626; --bad-soft: #fee2e2;
  --violet: #7c3aed; --violet-soft: #efe9ff; --orange: #ea580c; --orange-soft: #fff1e6; --teal: #0f766e; --teal-soft: #d8f3ef;
  --paper: #ffffff; --paper-ink: #1b2436; --paper-line: #d9dfe9;
  --shadow: 0 1px 2px rgba(23, 32, 51, .05), 0 10px 30px rgba(23, 32, 51, .08);
  --shadow-sm: 0 1px 2px rgba(23, 32, 51, .06);
  --r: 14px; --r-sm: 9px; --r-xs: 6px;
  --font: 'Noto Sans KR', 'Apple SD Gothic Neo', 'Malgun Gothic', system-ui, -apple-system, sans-serif;
  --mono: ui-monospace, 'Cascadia Mono', Consolas, monospace;
}
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --bg: #0f141c; --surface: #171e2a; --surface-2: #1e2736; --surface-3: #263142;
    --fg: #e8edf5; --fg-2: #c3ccd9; --muted: #8e9bb0; --line: #2a3444; --line-2: #3b4860;
    --accent: #6a97ff; --accent-2: #8fb1ff; --accent-soft: #1b2a48; --accent-soft-2: #233864; --on-accent: #ffffff;
    --ok: #4ade80; --ok-soft: #12351f; --warn: #fbbf24; --warn-soft: #3a2a08; --bad: #f87171; --bad-soft: #3d1515;
    --violet: #b79bff; --violet-soft: #2a2246; --orange: #fb923c; --orange-soft: #3b2412; --teal: #5eead4; --teal-soft: #0f3330;
    --paper: #fbfbf8; --paper-ink: #1b2436; --paper-line: #d9dfe9;
    --shadow: 0 1px 2px rgba(0, 0, 0, .3), 0 10px 30px rgba(0, 0, 0, .35);
    --shadow-sm: 0 1px 2px rgba(0, 0, 0, .3);
    color-scheme: dark;
  }
}
:root[data-theme="dark"] {
  --bg: #0f141c; --surface: #171e2a; --surface-2: #1e2736; --surface-3: #263142;
  --fg: #e8edf5; --fg-2: #c3ccd9; --muted: #8e9bb0; --line: #2a3444; --line-2: #3b4860;
  --accent: #6a97ff; --accent-2: #8fb1ff; --accent-soft: #1b2a48; --accent-soft-2: #233864; --on-accent: #ffffff;
  --ok: #4ade80; --ok-soft: #12351f; --warn: #fbbf24; --warn-soft: #3a2a08; --bad: #f87171; --bad-soft: #3d1515;
  --violet: #b79bff; --violet-soft: #2a2246; --orange: #fb923c; --orange-soft: #3b2412; --teal: #5eead4; --teal-soft: #0f3330;
  --paper: #fbfbf8; --paper-ink: #1b2436; --paper-line: #d9dfe9;
  --shadow: 0 1px 2px rgba(0, 0, 0, .3), 0 10px 30px rgba(0, 0, 0, .35);
  --shadow-sm: 0 1px 2px rgba(0, 0, 0, .3);
  color-scheme: dark;
}

* { box-sizing: border-box; }
[hidden] { display: none !important; }
html { -webkit-text-size-adjust: 100%; }
body { margin: 0; background: var(--bg); color: var(--fg); font-family: var(--font); font-size: 15px; line-height: 1.55; font-variant-numeric: tabular-nums; }
body::before { content: ""; position: fixed; inset: 0 0 auto; height: env(safe-area-inset-top, 0px); z-index: 60; background: var(--surface); }
a { color: inherit; text-decoration: none; }
button { font: inherit; color: inherit; cursor: pointer; }
input, select, textarea { font: inherit; color: inherit; }
img, svg { max-width: 100%; }
h1, h2, h3, h4 { margin: 0; line-height: 1.3; text-wrap: balance; }
p { margin: 0; }
i { font-family: 'Times New Roman', 'Noto Serif KR', Georgia, serif; font-style: italic; }
small { font-size: .85em; color: var(--muted); }
:focus-visible { outline: 2px solid var(--accent); outline-offset: 2px; }
@media (prefers-reduced-motion: reduce) { *, *::before, *::after { animation: none !important; transition: none !important; } }

.wrap { max-width: 1180px; margin: 0 auto; padding-left: max(16px, env(safe-area-inset-left, 0px)); padding-right: max(16px, env(safe-area-inset-right, 0px)); }
.sr { position: absolute; width: 1px; height: 1px; overflow: hidden; clip: rect(0 0 0 0); }
.ic { width: 1.1em; height: 1.1em; vertical-align: -0.2em; fill: none; stroke: currentColor; stroke-width: 1.8; stroke-linecap: round; stroke-linejoin: round; flex: none; }

/* ---------- 헤더 ---------- */
.hdr { position: sticky; top: env(safe-area-inset-top, 0px); z-index: 50; background: var(--surface); border-bottom: 1px solid var(--line); }
.hdr-in { display: flex; align-items: center; gap: 28px; height: 64px; }
.logo { display: flex; align-items: center; gap: 8px; font-weight: 900; font-size: 22px; letter-spacing: -.02em; }
.logo .ic { width: 30px; height: 30px; color: var(--accent); stroke-width: 2; }
.logo b { color: var(--accent); } .logo span { color: var(--fg); font-weight: 900; }
.nav { display: flex; gap: 4px; }
.nav a { padding: 8px 12px; border-radius: 8px; font-weight: 500; color: var(--fg-2); }
.nav a:hover { background: var(--surface-2); color: var(--fg); }
.nav a.on { color: var(--accent); font-weight: 700; }
.hdr-sp { flex: 1; }
.srch { display: flex; align-items: center; gap: 6px; background: var(--surface-2); border: 1px solid transparent; border-radius: 999px; padding: 6px 12px; width: 240px; }
.srch:focus-within { border-color: var(--accent); background: var(--surface); }
.srch input { border: 0; background: transparent; outline: 0; width: 100%; min-width: 0; }
.srch .ic { color: var(--muted); }
.ibtn { position: relative; width: 40px; height: 40px; border-radius: 10px; border: 0; background: transparent; display: inline-flex; align-items: center; justify-content: center; color: var(--fg-2); }
.ibtn:hover { background: var(--surface-2); }
.ibtn .ic { width: 22px; height: 22px; }
.badge-n { position: absolute; top: 4px; right: 4px; min-width: 18px; height: 18px; padding: 0 5px; border-radius: 9px; background: var(--accent); color: var(--on-accent); font-size: 11px; font-weight: 700; display: flex; align-items: center; justify-content: center; }
.hdr-acts { display: flex; align-items: center; gap: 4px; }

/* ---------- 모바일 탭바 ---------- */
.tabbar { display: none; position: fixed; left: 0; right: 0; bottom: 0; z-index: 50; background: var(--surface); border-top: 1px solid var(--line); padding: 6px max(10px, env(safe-area-inset-right, 0px)) calc(6px + env(safe-area-inset-bottom, 0px)) max(10px, env(safe-area-inset-left, 0px)); }
.tabbar a { flex: 1; display: flex; flex-direction: column; align-items: center; gap: 2px; font-size: 11px; color: var(--muted); padding: 4px 0; border-radius: 8px; }
.tabbar a .ic { width: 22px; height: 22px; }
.tabbar a.on { color: var(--accent); font-weight: 700; }

/* ---------- 공통 요소 ---------- */
.btn { display: inline-flex; align-items: center; justify-content: center; gap: 6px; border-radius: 10px; border: 1px solid var(--line-2); background: var(--surface); padding: 10px 18px; font-weight: 600; line-height: 1.2; white-space: nowrap; transition: background .15s, border-color .15s; }
.btn:hover { background: var(--surface-2); }
.btn:disabled { opacity: .5; cursor: default; }
.btn-p { background: var(--accent); border-color: var(--accent); color: var(--on-accent); }
.btn-p:hover { background: var(--accent-2); border-color: var(--accent-2); }
.btn-o { border-color: var(--accent); color: var(--accent); background: var(--surface); }
.btn-o:hover { background: var(--accent-soft); }
.btn-g { border-color: transparent; background: transparent; color: var(--fg-2); }
.btn-g:hover { background: var(--surface-2); }
.btn-sm { padding: 6px 12px; font-size: 13px; border-radius: 8px; }
.btn-lg { padding: 13px 24px; font-size: 16px; border-radius: 12px; }
.btn-blk { width: 100%; }
.btn-danger { color: var(--bad); border-color: var(--bad); }
.chips { display: flex; flex-wrap: wrap; gap: 8px; }
.chip { border: 1px solid var(--line-2); background: var(--surface); border-radius: 999px; padding: 6px 14px; font-size: 13.5px; font-weight: 500; color: var(--fg-2); }
.chip:hover { border-color: var(--accent); color: var(--accent); }
.chip.on { background: var(--accent); border-color: var(--accent); color: var(--on-accent); font-weight: 700; }
.chip.on-soft { background: var(--accent-soft); border-color: var(--accent); color: var(--accent); font-weight: 700; }
.tag { display: inline-flex; align-items: center; gap: 4px; padding: 2px 9px; border-radius: 999px; font-size: 12px; font-weight: 600; background: var(--accent-soft); color: var(--accent); }
.tag.g { background: var(--ok-soft); color: var(--ok); } .tag.v { background: var(--violet-soft); color: var(--violet); } .tag.o { background: var(--orange-soft); color: var(--orange); } .tag.w { background: var(--warn-soft); color: var(--warn); } .tag.n { background: var(--surface-3); color: var(--fg-2); } .tag.t { background: var(--teal-soft); color: var(--teal); } .tag.r { background: var(--bad-soft); color: var(--bad); }
.card { background: var(--surface); border: 1px solid var(--line); border-radius: var(--r); }
.card-p { padding: 22px; }
.sec { margin-top: 44px; }
.sec-h { display: flex; align-items: baseline; justify-content: space-between; gap: 12px; margin-bottom: 16px; }
.sec-h h2 { font-size: 21px; font-weight: 800; letter-spacing: -.01em; }
.sec-h a, .sec-h button.lnk { color: var(--muted); font-size: 14px; border: 0; background: none; padding: 0; }
.sec-h a:hover, .sec-h button.lnk:hover { color: var(--accent); }
.page-t { font-size: 28px; font-weight: 900; letter-spacing: -.02em; margin-top: 28px; }
.page-d { color: var(--muted); margin-top: 6px; }
.crumb { display: flex; flex-wrap: wrap; gap: 6px; font-size: 13px; color: var(--muted); margin-top: 18px; }
.crumb a:hover { color: var(--accent); }
.crumb span::before { content: "›"; margin-right: 6px; }
.muted { color: var(--muted); }
.row { display: flex; align-items: center; gap: 10px; flex-wrap: wrap; }
.grow { flex: 1; min-width: 0; }
.hint { font-size: 13px; color: var(--muted); }
.empty { text-align: center; padding: 56px 20px; color: var(--muted); border: 1px dashed var(--line-2); border-radius: var(--r); }
.empty .ic { width: 40px; height: 40px; color: var(--line-2); margin-bottom: 8px; }
.tbl { width: 100%; border-collapse: collapse; font-size: 14px; }
.tbl th, .tbl td { padding: 10px 12px; border-bottom: 1px solid var(--line); text-align: left; vertical-align: top; }
.tbl th { color: var(--muted); font-weight: 600; font-size: 13px; background: var(--surface-2); }
.tbl-w { overflow-x: auto; }
.m { font-size: 1.08em; margin: 6px 0 2px; }
.m.sys { display: inline-flex; flex-direction: column; gap: 2px; padding-left: 10px; border-left: 2px solid currentColor; border-radius: 3px 0 0 3px; }
.fr { display: inline-flex; flex-direction: column; align-items: center; vertical-align: middle; font-size: .88em; line-height: 1.15; margin: 0 2px; }
.fr > span:first-child { border-bottom: 1px solid currentColor; padding: 0 3px; }
.fr > span:last-child { padding: 0 3px; }
.rt { white-space: nowrap; } .rt > span { border-top: 1px solid currentColor; padding: 0 1px 0 2px; }
.sum { display: inline-flex; flex-direction: column; align-items: center; line-height: 1; vertical-align: middle; margin-right: 4px; font-size: 1.3em; }
.sum > span { font-size: .5em; }

/* ---------- 표지 ---------- */
.cover { --c1: #dbe9ff; --c2: #8fb6ff; --ink: #1e3a8a; position: relative; aspect-ratio: 3 / 4; width: 100%; max-width: 100%; border-radius: 6px 10px 10px 6px; background: linear-gradient(160deg, var(--c1) 0%, var(--c2) 100%); color: var(--ink); overflow: hidden; box-shadow: inset 6px 0 10px -8px rgba(0, 0, 0, .35), 0 6px 16px rgba(23, 32, 51, .14); display: flex; flex-direction: column; padding: 9% 9% 8%; container-type: inline-size; }
.cover::before { content: ""; position: absolute; left: 0; top: 0; bottom: 0; width: 5%; background: rgba(255, 255, 255, .35); }
.cover::after { content: ""; position: absolute; right: -18%; bottom: -14%; width: 70%; aspect-ratio: 1; border-radius: 50%; background: rgba(255, 255, 255, .28); }
.cv-brand { font-size: 7cqw; font-weight: 700; letter-spacing: .04em; opacity: .75; text-transform: uppercase; }
.cv-title { margin-top: auto; font-size: 10.5cqw; font-weight: 900; line-height: 1.22; letter-spacing: -.02em; word-break: keep-all; position: relative; }
.cv-sub { font-size: 6.2cqw; margin-top: 4%; opacity: .85; font-weight: 500; line-height: 1.3; word-break: keep-all; position: relative; }
.cv-meta { margin-top: 8%; font-size: 5.6cqw; font-weight: 600; opacity: .8; position: relative; }
.cv-mark { position: absolute; top: 9%; right: 9%; width: 16%; aspect-ratio: 1; border-radius: 50%; background: var(--ink); opacity: .12; }
.cv-strip { position: absolute; left: 5%; right: 0; bottom: 0; height: 4%; background: var(--ink); opacity: .55; }

/* ---------- 교재 카드 ---------- */
.books { display: grid; grid-template-columns: repeat(auto-fill, minmax(190px, 1fr)); gap: 22px 18px; }
.bk { display: flex; flex-direction: column; gap: 10px; min-width: 0; }
.bk .cover { transition: transform .2s; }
.bk:hover .cover { transform: translateY(-3px); }
.bk-t { font-weight: 700; font-size: 14.5px; line-height: 1.35; display: -webkit-box; -webkit-line-clamp: 2; -webkit-box-orient: vertical; overflow: hidden; }
.bk-s { font-size: 12.5px; color: var(--muted); display: -webkit-box; -webkit-line-clamp: 1; -webkit-box-orient: vertical; overflow: hidden; }
.bk-m { display: flex; align-items: center; gap: 6px; font-size: 12px; color: var(--muted); flex-wrap: wrap; }
.bk-acts { display: flex; gap: 6px; }
.bk-acts .btn { flex: 1; }
.bk-wish { position: absolute; top: 8px; right: 8px; width: 30px; height: 30px; border-radius: 50%; border: 0; background: rgba(255, 255, 255, .85); color: #5b6472; display: inline-flex; align-items: center; justify-content: center; z-index: 2; }
.bk-wish.on { color: #e11d48; }
.bk-wish .ic { width: 16px; height: 16px; }
.bk-wish.on .ic { fill: currentColor; }
.cover-wrap { position: relative; }
.rail { display: grid; grid-auto-flow: column; grid-auto-columns: minmax(180px, 1fr); gap: 18px; overflow-x: auto; padding-bottom: 8px; scroll-snap-type: x proximity; }
.rail > * { scroll-snap-align: start; }
.rail::-webkit-scrollbar { height: 6px; } .rail::-webkit-scrollbar-thumb { background: var(--line-2); border-radius: 3px; }
.star { color: #f59e0b; }

/* ---------- 홈 ---------- */
.hero { margin-top: 20px; background: linear-gradient(135deg, var(--accent-soft) 0%, var(--surface) 60%, var(--surface-2) 100%); border: 1px solid var(--line); border-radius: 22px; padding: 44px 48px; display: grid; grid-template-columns: 1.1fr 1fr; gap: 30px; align-items: center; overflow: hidden; position: relative; }
.hero h1 { font-size: 38px; font-weight: 900; letter-spacing: -.03em; line-height: 1.25; }
.hero h1 b { color: var(--accent); }
.hero p { margin-top: 14px; color: var(--fg-2); font-size: 16px; max-width: 34em; }
.hero-acts { display: flex; gap: 10px; margin-top: 26px; flex-wrap: wrap; }
.hero-books { position: relative; height: 290px; }
.hero-books .cover { position: absolute; width: 180px; }
.hero-books .cover:nth-child(1) { left: 6%; top: 36px; transform: rotate(-7deg); z-index: 1; }
.hero-books .cover:nth-child(2) { left: 36%; top: 6px; z-index: 3; width: 200px; }
.hero-books .cover:nth-child(3) { left: 66%; top: 40px; transform: rotate(7deg); z-index: 2; }
.feats { display: grid; grid-template-columns: repeat(4, 1fr); gap: 14px; margin-top: 22px; }
.feat { display: flex; gap: 12px; align-items: flex-start; padding: 16px; background: var(--surface); border: 1px solid var(--line); border-radius: var(--r); }
.feat-i { width: 42px; height: 42px; border-radius: 12px; display: inline-flex; align-items: center; justify-content: center; flex: none; }
.feat-i .ic { width: 22px; height: 22px; }
.feat-i.b { background: var(--accent-soft); color: var(--accent); } .feat-i.g { background: var(--ok-soft); color: var(--ok); } .feat-i.v { background: var(--violet-soft); color: var(--violet); } .feat-i.o { background: var(--orange-soft); color: var(--orange); }
.feat b { display: block; font-size: 15px; } .feat small { display: block; margin-top: 2px; }
.cta { margin-top: 44px; background: var(--accent); color: var(--on-accent); border-radius: 22px; padding: 36px 40px; display: grid; grid-template-columns: 1fr auto; gap: 24px; align-items: center; position: relative; overflow: hidden; }
.cta::after { content: ""; position: absolute; right: -60px; top: -80px; width: 280px; height: 280px; border-radius: 50%; background: rgba(255, 255, 255, .12); }
.cta h2 { font-size: 26px; font-weight: 900; letter-spacing: -.02em; }
.cta p { margin-top: 8px; opacity: .9; }
.cta .btn { background: var(--surface); color: var(--accent); border-color: transparent; position: relative; }
.cta .btn:hover { background: var(--accent-soft); }
.cta-steps { display: flex; gap: 8px; margin-top: 16px; flex-wrap: wrap; }
.cta-steps span { background: rgba(255, 255, 255, .18); border-radius: 999px; padding: 4px 12px; font-size: 13px; font-weight: 600; }
.cats { display: grid; grid-template-columns: repeat(3, 1fr); gap: 14px; }
.cat { display: flex; align-items: center; gap: 14px; padding: 18px; background: var(--surface); border: 1px solid var(--line); border-radius: var(--r); transition: border-color .15s; }
.cat:hover { border-color: var(--accent); }
.cat b { display: block; font-size: 15px; } .cat small { display: block; }
.band { margin-top: 44px; display: grid; grid-template-columns: 1fr 1fr; gap: 14px; }
.band .card-p { display: flex; flex-direction: column; gap: 8px; }
.band h3 { font-size: 18px; font-weight: 800; }

/* ---------- 둘러보기 ---------- */
.browse { display: grid; grid-template-columns: 220px 1fr; gap: 28px; margin-top: 24px; }
.filters { position: sticky; top: calc(76px + env(safe-area-inset-top, 0px)); align-self: start; display: flex; flex-direction: column; gap: 22px; }
.filters h4 { font-size: 13px; color: var(--muted); font-weight: 700; letter-spacing: .04em; margin-bottom: 8px; }
.fl { display: flex; flex-direction: column; gap: 6px; }
.fl label { display: flex; align-items: center; gap: 8px; font-size: 14px; cursor: pointer; }
.fl input { accent-color: var(--accent); }
.browse-top { display: flex; align-items: center; gap: 10px; flex-wrap: wrap; margin-bottom: 16px; }
.browse-top .srch { width: 100%; max-width: 420px; }
.browse-top select { border: 1px solid var(--line-2); border-radius: 8px; padding: 6px 10px; background: var(--surface); }
.cnt { font-size: 13px; color: var(--muted); }

/* ---------- 교재 상세 ---------- */
.detail { display: grid; grid-template-columns: 300px 1fr; gap: 36px; margin-top: 18px; }
.detail .cover { max-width: 300px; }
.detail-h h1 { font-size: 26px; font-weight: 900; letter-spacing: -.02em; margin-top: 8px; }
.detail-h .tags { display: flex; gap: 6px; flex-wrap: wrap; }
.detail-d { margin-top: 14px; color: var(--fg-2); max-width: 46em; }
.kv { display: grid; grid-template-columns: auto 1fr; gap: 8px 16px; margin-top: 18px; font-size: 14px; }
.kv dt { color: var(--muted); display: flex; align-items: center; gap: 6px; } .kv dd { margin: 0; font-weight: 500; }
.detail-acts { display: flex; gap: 10px; margin-top: 22px; flex-wrap: wrap; }
.thumbs { display: flex; gap: 8px; margin-top: 14px; }
.thumbs button { width: 64px; aspect-ratio: 3/4; border: 1px solid var(--line-2); border-radius: 6px; background: var(--paper); padding: 4px; display: flex; flex-direction: column; gap: 2px; overflow: hidden; }
.thumbs button span { height: 3px; background: var(--paper-line); border-radius: 2px; } .thumbs button span:nth-child(odd) { width: 80%; }
.tabs { display: flex; gap: 0; border-bottom: 1px solid var(--line); margin-top: 32px; overflow-x: auto; }
.tabs button { border: 0; background: none; padding: 12px 18px; font-weight: 600; color: var(--muted); border-bottom: 2px solid transparent; margin-bottom: -1px; white-space: nowrap; }
.tabs button.on { color: var(--accent); border-color: var(--accent); }
.tabp { padding-top: 24px; }
.two { display: grid; grid-template-columns: 1fr 1fr; gap: 28px; }
.ul { margin: 0; padding: 0; list-style: none; display: flex; flex-direction: column; gap: 10px; }
.ul li { display: flex; gap: 10px; align-items: flex-start; }
.ul li .ic { color: var(--accent); margin-top: 3px; }
.feat-l li .ic { width: 22px; height: 22px; padding: 3px; background: var(--accent-soft); border-radius: 6px; }
.toc { margin: 0; padding: 0; list-style: none; }
.toc li { display: flex; justify-content: space-between; gap: 10px; padding: 10px 0; border-bottom: 1px dashed var(--line); }
.toc li.ch { font-weight: 700; }
.toc li.sub { padding-left: 18px; color: var(--fg-2); }
.toc li span:last-child { color: var(--muted); font-variant-numeric: tabular-nums; }
.review { display: flex; flex-direction: column; gap: 6px; padding: 14px 0; border-bottom: 1px solid var(--line); }
.review b { font-size: 14px; }

/* ---------- 문제 카드 ---------- */
.probs { display: grid; gap: 18px; }
.prob { position: relative; display: flex; flex-direction: column; gap: 6px; padding: 14px 14px 12px; border: 1px solid var(--line); border-radius: var(--r-sm); background: var(--surface); min-width: 0; }
.prob-h { display: flex; align-items: center; gap: 8px; font-size: 12px; color: var(--muted); }
.prob-n { font-weight: 900; color: var(--accent); font-size: 15px; }
.prob-q { font-size: 15px; line-height: 1.7; }
.prob .fig { width: 180px; max-width: 100%; display: block; margin: 6px auto 0; }
.prob-acts { display: flex; gap: 6px; margin-top: 4px; flex-wrap: wrap; }
.prob-sol { margin-top: 8px; padding: 10px 12px; border-radius: 8px; background: var(--accent-soft); font-size: 14px; line-height: 1.7; }
.prob-sol b { color: var(--accent); }
.fig { color: var(--fg-2); }
.fg-grid { stroke: var(--line); stroke-width: 1; } .fg-axis { stroke: currentColor; stroke-width: 1.4; fill: none; }
.fg-curve { stroke: var(--accent); stroke-width: 2.4; fill: none; } .fg-curve2 { stroke: var(--orange); }
.fg-pt { fill: var(--accent); stroke: var(--surface); stroke-width: 1.5; }
.fg-lbl { font-size: 11px; fill: currentColor; font-family: var(--font); }
.fg-shape { fill: var(--accent-soft); stroke: currentColor; stroke-width: 1.6; }
.paper .fig, .paper .fg-lbl { color: var(--paper-ink); }
.paper .fg-grid { stroke: var(--paper-line); } .paper .fg-shape { fill: #e8f0ff; } .paper .fg-pt { stroke: var(--paper); }

/* ---------- 종이 페이지 ---------- */
.paper { background: var(--paper); color: var(--paper-ink); border: 1px solid var(--line); border-radius: 4px; box-shadow: var(--shadow-sm); aspect-ratio: 1 / 1.38; width: 100%; max-width: 100%; padding: 7% 7.5% 6%; display: flex; flex-direction: column; gap: 12px; position: relative; overflow: hidden; font-size: 13.5px; line-height: 1.6; }
.paper-hd { display: flex; justify-content: space-between; font-size: 11px; color: #6b7788; border-bottom: 1px solid var(--paper-line); padding-bottom: 6px; }
.paper-ft { margin-top: auto; text-align: center; font-size: 11px; color: #6b7788; }
.paper h2 { font-size: 19px; font-weight: 900; }
.paper h3 { font-size: 15px; font-weight: 800; color: #1d4ed8; }
.paper .probs { grid-template-columns: 1fr 1fr; gap: 10px 16px; }
.paper .prob { border: 0; padding: 0; background: transparent; color: inherit; gap: 4px; }
.paper .prob-q { font-size: 12.5px; line-height: 1.6; }
.paper .prob-n { color: #1d4ed8; font-size: 13px; }
.paper .prob-h { color: #6b7788; font-size: 10.5px; }
.paper .prob .fig { width: 130px; margin: 2px 0 0; }
.paper .box { border: 1px solid #c7d4ea; background: #f2f6ff; border-radius: 8px; padding: 10px 12px; font-size: 12.5px; }
.paper .box b { color: #1d4ed8; }
.paper .concept-fm { font-size: 14px; text-align: center; padding: 8px; border-top: 1px dashed #c7d4ea; border-bottom: 1px dashed #c7d4ea; margin-top: 6px; }
.paper .toc { font-size: 13px; }
.paper .toc li { border-color: #e3e8f0; padding: 6px 0; }
.paper .toc li.sub { color: #3b4658; }
.paper.cover-page { padding: 0; }
.paper.cover-page .cover { aspect-ratio: auto; height: 100%; border-radius: 0; box-shadow: none; }
.paper .ans { display: grid; grid-template-columns: 1fr 1fr; gap: 8px 16px; font-size: 12.5px; }
.paper .ans > div { display: flex; flex-direction: column; gap: 3px; padding-bottom: 6px; border-bottom: 1px dashed #e3e8f0; }
.paper .ans b { color: #1d4ed8; }
.paper .ans .s { color: #3b4658; font-size: 12px; }
.paper .ans.only { grid-template-columns: repeat(4, 1fr); }
.paper .ans.only > div { flex-direction: row; gap: 8px; }
.paper .tag { font-size: 10px; padding: 1px 7px; }
.paper .tag.n { background: #e8edf5; color: #3b4658; } .paper .tag.g { background: #dcfce7; color: #15803d; } .paper .tag.o { background: #fff1e6; color: #c2410c; } .paper .tag.v { background: #efe9ff; color: #6d28d9; } .paper .tag.r { background: #fee2e2; color: #b91c1c; }

/* ---------- 스테퍼 ---------- */
.stepper { display: flex; align-items: center; justify-content: center; gap: 0; margin: 26px auto 0; max-width: 640px; }
.step { display: flex; flex-direction: column; align-items: center; gap: 6px; font-size: 12.5px; color: var(--muted); min-width: 72px; }
.step i { width: 30px; height: 30px; border-radius: 50%; border: 2px solid var(--line-2); display: flex; align-items: center; justify-content: center; font-style: normal; font-weight: 700; font-size: 13px; background: var(--surface); }
.step.on { color: var(--accent); font-weight: 700; } .step.on i { background: var(--accent); border-color: var(--accent); color: var(--on-accent); }
.step.done i { border-color: var(--accent); color: var(--accent); }
.step-ln { flex: 1; height: 2px; background: var(--line-2); margin: 0 4px 22px; max-width: 110px; }
.step-ln.done { background: var(--accent); }

/* ---------- 만들기 폼 ---------- */
.wiz { display: grid; grid-template-columns: 1fr 320px; gap: 28px; margin-top: 28px; }
.wiz-main { display: flex; flex-direction: column; gap: 22px; min-width: 0; }
.fsec { display: grid; grid-template-columns: 150px 1fr; gap: 14px; align-items: start; padding: 18px 0; border-bottom: 1px solid var(--line); }
.fsec:last-child { border-bottom: 0; }
.fsec-l b { display: flex; align-items: center; gap: 8px; font-size: 15px; }
.fsec-l b i { width: 22px; height: 22px; border-radius: 50%; background: var(--accent-soft); color: var(--accent); display: inline-flex; align-items: center; justify-content: center; font-style: normal; font-size: 12px; font-weight: 800; }
.fsec-l small { display: block; margin-top: 4px; line-height: 1.4; }
.fsec-r { display: flex; flex-direction: column; gap: 10px; min-width: 0; }
.seg { display: inline-flex; flex-wrap: wrap; gap: 6px; }
.seg button { border: 1px solid var(--line-2); background: var(--surface); border-radius: 9px; padding: 8px 16px; font-weight: 600; color: var(--fg-2); }
.seg button.on { background: var(--accent); border-color: var(--accent); color: var(--on-accent); }
.seg.sm button { padding: 6px 12px; font-size: 13px; }
.units { display: grid; grid-template-columns: repeat(auto-fill, minmax(190px, 1fr)); gap: 8px; }
.unit { display: flex; align-items: center; gap: 8px; border: 1px solid var(--line-2); border-radius: 9px; padding: 9px 12px; font-size: 14px; background: var(--surface); text-align: left; }
.unit.on { border-color: var(--accent); background: var(--accent-soft); color: var(--accent); font-weight: 700; }
.unit small { margin-left: auto; font-size: 11px; }
.ckl { display: flex; flex-wrap: wrap; gap: 8px 18px; }
.ckl label { display: flex; align-items: center; gap: 7px; font-size: 14px; }
.ckl input { accent-color: var(--accent); width: 16px; height: 16px; }
.inp { width: 100%; border: 1px solid var(--line-2); border-radius: 9px; padding: 9px 12px; background: var(--surface); }
.inp:focus { outline: 0; border-color: var(--accent); }
.rng { display: flex; align-items: center; gap: 12px; }
.rng input[type=range] { flex: 1; accent-color: var(--accent); }
.rng output { font-weight: 800; color: var(--accent); min-width: 72px; text-align: right; }
.summary { position: sticky; top: calc(84px + env(safe-area-inset-top, 0px)); align-self: start; }
.summary h3 { font-size: 15px; font-weight: 800; margin-bottom: 12px; }
.summary dl { display: grid; grid-template-columns: auto 1fr; gap: 8px 12px; font-size: 13.5px; margin: 0; }
.summary dt { color: var(--muted); } .summary dd { margin: 0; font-weight: 600; text-align: right; }
.summary .cover { max-width: 150px; margin: 0 auto 14px; }
.est { margin-top: 14px; padding-top: 14px; border-top: 1px solid var(--line); display: flex; flex-direction: column; gap: 6px; font-size: 13.5px; }
.est div { display: flex; justify-content: space-between; }
.est b { color: var(--accent); }
.wiz-acts { display: flex; justify-content: space-between; gap: 10px; margin-top: 10px; flex-wrap: wrap; }

/* ---------- 생성 진행 ---------- */
.gen { max-width: 560px; margin: 40px auto; text-align: center; }
.gen h2 { font-size: 22px; font-weight: 900; }
.gen-steps { display: flex; flex-direction: column; gap: 10px; margin-top: 26px; text-align: left; }
.gstep { display: flex; align-items: center; gap: 12px; padding: 12px 14px; border: 1px solid var(--line); border-radius: 10px; background: var(--surface); color: var(--muted); }
.gstep i { width: 24px; height: 24px; border-radius: 50%; border: 2px solid var(--line-2); display: inline-flex; align-items: center; justify-content: center; font-style: normal; flex: none; }
.gstep.run { color: var(--fg); border-color: var(--accent); } .gstep.run i { border-color: var(--accent); border-top-color: transparent; animation: spin 1s linear infinite; }
.gstep.ok { color: var(--fg); } .gstep.ok i { background: var(--ok); border-color: var(--ok); color: #fff; }
.gstep.ok i .ic { width: 14px; height: 14px; stroke-width: 3; }
@keyframes spin { to { transform: rotate(360deg); } }
.gbar { height: 8px; background: var(--surface-3); border-radius: 4px; margin-top: 22px; overflow: hidden; }
.gbar > div { height: 100%; background: var(--accent); border-radius: 4px; transition: width .4s; }

/* ---------- 미리보기 / 편집 ---------- */
.editor { display: grid; grid-template-columns: 120px 1fr 300px; gap: 20px; margin-top: 22px; align-items: start; }
.pg-list { display: flex; flex-direction: column; gap: 8px; max-height: 70vh; overflow-y: auto; padding-right: 4px; }
.pg-th { border: 2px solid var(--line); border-radius: 6px; background: var(--paper); aspect-ratio: 1/1.38; padding: 8px; display: flex; flex-direction: column; gap: 3px; cursor: pointer; position: relative; }
.pg-th.on { border-color: var(--accent); }
.pg-th span { height: 3px; background: var(--paper-line); border-radius: 2px; } .pg-th span:nth-child(3n) { width: 60%; }
.pg-th b { position: absolute; bottom: 4px; right: 6px; font-size: 10px; color: #6b7788; }
.pg-th.cv { background: linear-gradient(160deg, var(--c1), var(--c2)); } .pg-th.cv span { display: none; }
.pg-view { min-width: 0; }
.pg-view .paper { max-width: 640px; margin: 0 auto; }
.pg-nav { display: flex; align-items: center; justify-content: center; gap: 12px; margin-top: 12px; font-size: 14px; color: var(--muted); }
.panel { display: flex; flex-direction: column; gap: 18px; }
.panel h4 { font-size: 14px; font-weight: 800; margin-bottom: 8px; }
.swatches { display: flex; gap: 8px; flex-wrap: wrap; }
.sw { width: 30px; height: 30px; border-radius: 50%; border: 2px solid transparent; background: linear-gradient(160deg, var(--c1), var(--c2)); cursor: pointer; }
.sw.on { border-color: var(--accent); box-shadow: 0 0 0 2px var(--surface) inset; }
.plist { display: flex; flex-direction: column; gap: 6px; max-height: 320px; overflow-y: auto; }
.pl { display: flex; align-items: center; gap: 6px; padding: 7px 8px; border: 1px solid var(--line); border-radius: 8px; font-size: 12.5px; }
.pl b { color: var(--accent); min-width: 26px; }
.pl .grow { white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }
.pl .ibtn { width: 26px; height: 26px; border-radius: 6px; } .pl .ibtn .ic { width: 15px; height: 15px; }
.tgl { display: flex; align-items: center; justify-content: space-between; gap: 10px; font-size: 14px; padding: 6px 0; }
.sw-tgl { position: relative; width: 40px; height: 22px; border-radius: 11px; background: var(--line-2); border: 0; flex: none; transition: background .15s; }
.sw-tgl::after { content: ""; position: absolute; top: 2px; left: 2px; width: 18px; height: 18px; border-radius: 50%; background: #fff; transition: left .15s; }
.sw-tgl.on { background: var(--accent); } .sw-tgl.on::after { left: 20px; }

/* ---------- 공개 · 주문 ---------- */
.pub-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 20px; margin-top: 24px; }
.radio-l { display: flex; flex-direction: column; gap: 8px; }
.radio-l label { display: flex; gap: 10px; align-items: flex-start; padding: 12px; border: 1px solid var(--line-2); border-radius: 10px; cursor: pointer; }
.radio-l label.on { border-color: var(--accent); background: var(--accent-soft); }
.radio-l input { accent-color: var(--accent); margin-top: 3px; }
.radio-l b { display: block; font-size: 14px; } .radio-l small { display: block; }
.opt-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 12px; }
.opt { display: flex; flex-direction: column; gap: 6px; }
.opt > span { font-size: 12.5px; color: var(--muted); font-weight: 600; }
.qty { display: inline-flex; align-items: center; border: 1px solid var(--line-2); border-radius: 8px; overflow: hidden; }
.qty button { width: 32px; height: 32px; border: 0; background: var(--surface-2); }
.qty input { width: 52px; text-align: center; border: 0; background: transparent; }
.price-box { margin-top: 14px; padding: 14px; border-radius: 10px; background: var(--surface-2); display: flex; flex-direction: column; gap: 6px; font-size: 14px; }
.price-box div { display: flex; justify-content: space-between; }
.price-box .tot { font-size: 17px; font-weight: 900; padding-top: 8px; border-top: 1px solid var(--line-2); margin-top: 4px; }
.price-box .tot span:last-child { color: var(--accent); }

/* ---------- 열람 뷰어 ---------- */
.reader { display: grid; grid-template-columns: 240px 1fr; gap: 24px; margin-top: 18px; align-items: start; }
.reader-toc { position: sticky; top: calc(76px + env(safe-area-inset-top, 0px)); max-height: calc(100vh - 100px); overflow-y: auto; }
.reader-toc .toc li { cursor: pointer; padding: 8px 6px; border-radius: 6px; border: 0; }
.reader-toc .toc li:hover { background: var(--surface-2); } .reader-toc .toc li.on { background: var(--accent-soft); color: var(--accent); }
.reader-bar { display: flex; align-items: center; gap: 10px; flex-wrap: wrap; padding: 10px 14px; background: var(--surface); border: 1px solid var(--line); border-radius: 10px; margin-bottom: 14px; }
.reader-bar b { font-size: 15px; }
.reader-page { background: var(--surface); border: 1px solid var(--line); border-radius: var(--r); padding: 28px; min-height: 60vh; }
.reader-page .probs { grid-template-columns: 1fr 1fr; }
.reader-page .concept { padding: 18px; background: var(--accent-soft); border-radius: 10px; margin-bottom: 18px; line-height: 1.75; }
.reader-page .concept b { color: var(--accent); display: block; margin-bottom: 4px; }
.reader-page h2 { font-size: 20px; font-weight: 900; margin-bottom: 14px; }
.reader-page h2 small { font-weight: 500; margin-left: 8px; }
.ask-panel { position: fixed; right: max(16px, env(safe-area-inset-right, 0px)); bottom: calc(16px + env(safe-area-inset-bottom, 0px)); width: min(400px, calc(100vw - 32px)); max-height: 70vh; overflow-y: auto; background: var(--surface); border: 1px solid var(--line); border-radius: 16px; box-shadow: var(--shadow); padding: 18px; z-index: 55; display: flex; flex-direction: column; gap: 12px; }
.ask-panel h4 { font-size: 15px; font-weight: 800; display: flex; align-items: center; gap: 8px; }
.ask-q { padding: 10px 12px; background: var(--surface-2); border-radius: 10px; font-size: 13.5px; }
.ask-a { padding: 12px; background: var(--accent-soft); border-radius: 10px; font-size: 14px; line-height: 1.7; }
.ask-a b { color: var(--accent); }
.ask-note { font-size: 12px; color: var(--muted); }
.ask-in { display: flex; gap: 6px; }
.solved { position: absolute; top: 10px; right: 10px; }
.prob.is-solved { border-color: var(--ok); }
.progress { height: 8px; background: var(--surface-3); border-radius: 4px; overflow: hidden; }
.progress > div { height: 100%; background: var(--ok); }

/* ---------- 장바구니 / 주문 ---------- */
.cart { display: grid; grid-template-columns: 1fr 340px; gap: 28px; margin-top: 24px; align-items: start; }
.citem { display: grid; grid-template-columns: 70px 1fr auto; gap: 16px; padding: 16px 0; border-bottom: 1px solid var(--line); align-items: center; }
.citem .cover { width: 70px; }
.citem b { display: block; font-size: 15px; }
.citem small { display: block; margin-top: 4px; }
.citem-r { display: flex; flex-direction: column; align-items: flex-end; gap: 8px; }
.citem-r .price { font-weight: 800; font-size: 15px; }
.osum { position: sticky; top: calc(84px + env(safe-area-inset-top, 0px)); }
.osum h3 { font-size: 16px; font-weight: 800; margin-bottom: 12px; }
.form { display: grid; grid-template-columns: 1fr 1fr; gap: 12px; }
.form .full { grid-column: 1 / -1; }
.form label { display: flex; flex-direction: column; gap: 5px; font-size: 13px; color: var(--muted); font-weight: 600; }
.timeline { display: flex; justify-content: space-between; gap: 4px; margin-top: 20px; }
.tl { flex: 1; display: flex; flex-direction: column; align-items: center; gap: 6px; font-size: 12.5px; color: var(--muted); text-align: center; }
.tl i { width: 12px; height: 12px; border-radius: 50%; background: var(--line-2); }
.tl.on { color: var(--accent); font-weight: 700; } .tl.on i { background: var(--accent); box-shadow: 0 0 0 4px var(--accent-soft); }
.tl.done i { background: var(--accent); }
.done-box { max-width: 560px; margin: 50px auto; text-align: center; }
.done-box .ok-i { width: 72px; height: 72px; border-radius: 50%; background: var(--ok-soft); color: var(--ok); display: inline-flex; align-items: center; justify-content: center; margin-bottom: 16px; }
.done-box .ok-i .ic { width: 36px; height: 36px; stroke-width: 2.5; }
.done-box h2 { font-size: 24px; font-weight: 900; }

/* ---------- 마이페이지 ---------- */
.my { display: grid; grid-template-columns: 220px 1fr; gap: 28px; margin-top: 24px; align-items: start; }
.my-nav { display: flex; flex-direction: column; gap: 4px; }
.my-nav button { text-align: left; border: 0; background: none; padding: 10px 12px; border-radius: 8px; font-weight: 600; color: var(--fg-2); display: flex; align-items: center; gap: 8px; }
.my-nav button.on { background: var(--accent-soft); color: var(--accent); }
.my-prof { display: flex; align-items: center; gap: 12px; padding: 14px; margin-bottom: 10px; }
.avatar { width: 46px; height: 46px; border-radius: 50%; background: var(--accent-soft); color: var(--accent); display: inline-flex; align-items: center; justify-content: center; font-weight: 900; font-size: 18px; }
.order { padding: 16px 0; border-bottom: 1px solid var(--line); display: flex; flex-direction: column; gap: 8px; }
.order-h { display: flex; justify-content: space-between; gap: 10px; flex-wrap: wrap; font-size: 13.5px; }
.stat-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 12px; }
.stat { padding: 16px; background: var(--surface-2); border-radius: 10px; }
.stat b { display: block; font-size: 24px; font-weight: 900; color: var(--accent); }
.stat small { display: block; }

/* ---------- 이용안내 ---------- */
.guide-steps { display: grid; grid-template-columns: repeat(4, 1fr); gap: 14px; }
.gs { padding: 18px; background: var(--surface); border: 1px solid var(--line); border-radius: var(--r); }
.gs b { display: block; font-size: 15px; margin: 8px 0 4px; }
.gs .num { width: 28px; height: 28px; border-radius: 50%; background: var(--accent); color: var(--on-accent); display: inline-flex; align-items: center; justify-content: center; font-weight: 800; font-size: 13px; }
details { border: 1px solid var(--line); border-radius: 10px; padding: 0 16px; background: var(--surface); }
details + details { margin-top: 8px; }
summary { cursor: pointer; padding: 14px 0; font-weight: 700; list-style: none; display: flex; justify-content: space-between; }
summary::after { content: "+"; color: var(--muted); } details[open] summary::after { content: "−"; }
details p { padding: 0 0 14px; color: var(--fg-2); }

/* ---------- 토스트 / 모달 ---------- */
#toast { position: fixed; left: 50%; bottom: calc(24px + env(safe-area-inset-bottom, 0px)); transform: translateX(-50%); z-index: 70; display: flex; flex-direction: column; gap: 8px; pointer-events: none; }
.toast { background: var(--fg); color: var(--bg); padding: 10px 18px; border-radius: 999px; font-size: 14px; font-weight: 600; box-shadow: var(--shadow); animation: up .2s ease-out; }
@keyframes up { from { opacity: 0; transform: translateY(8px); } }
.modal-bg { position: fixed; inset: 0; background: rgba(10, 15, 25, .5); z-index: 65; display: flex; align-items: center; justify-content: center; padding: 16px; }
.modal { background: var(--surface); border-radius: 16px; padding: 24px; width: min(520px, 100%); box-shadow: var(--shadow); display: flex; flex-direction: column; gap: 14px; max-height: 90vh; overflow-y: auto; }
.modal h3 { font-size: 18px; font-weight: 800; }
.modal .paper { font-size: 12px; }

/* ---------- 푸터 ---------- */
.ftr { margin-top: 70px; border-top: 1px solid var(--line); background: var(--surface); }
.ftr-in { display: grid; grid-template-columns: 1.4fr 1fr 1fr 1fr; gap: 24px; padding-block: 36px 90px; font-size: 13.5px; }
.ftr h5 { font-size: 13px; margin: 0 0 10px; color: var(--muted); font-weight: 700; letter-spacing: .04em; }
.ftr ul { margin: 0; padding: 0; list-style: none; display: flex; flex-direction: column; gap: 6px; }
.ftr a:hover { color: var(--accent); }
.ftr .logo { font-size: 18px; margin-bottom: 10px; }

/* ---------- 반응형 ---------- */
@media (max-width: 960px) {
  .hero { grid-template-columns: 1fr; padding: 32px 26px; } .hero-books { height: 230px; max-width: 460px; }
  .hero-books .cover { width: 140px; } .hero-books .cover:nth-child(2) { width: 160px; }
  .feats { grid-template-columns: 1fr 1fr; } .cats { grid-template-columns: 1fr 1fr; }
  .browse { grid-template-columns: 1fr; } .filters { position: static; flex-direction: row; flex-wrap: wrap; gap: 16px 28px; padding: 14px; border: 1px solid var(--line); border-radius: var(--r); background: var(--surface); }
  .detail { grid-template-columns: 220px 1fr; gap: 24px; }
  .wiz { grid-template-columns: 1fr; } .summary { position: static; }
  .editor { grid-template-columns: 1fr; } .pg-list { flex-direction: row; max-height: none; overflow-x: auto; } .pg-th { width: 64px; flex: none; }
  .reader { grid-template-columns: 1fr; } .reader-toc { position: static; max-height: none; }
  .cart { grid-template-columns: 1fr; } .osum { position: static; }
  .my { grid-template-columns: 1fr; } .my-nav { flex-direction: row; flex-wrap: wrap; }
  .guide-steps { grid-template-columns: 1fr 1fr; } .ftr-in { grid-template-columns: 1fr 1fr; }
  .pub-grid { grid-template-columns: 1fr; } .two { grid-template-columns: 1fr; }
  .srch { width: 180px; }
}
@media (max-width: 640px) {
  body { padding-bottom: 70px; }
  .tabbar { display: flex; }
  .hdr-in { height: 56px; gap: 10px; } .nav, .hdr .srch { display: none; } .logo { font-size: 19px; }
  .hero { padding: 26px 20px; border-radius: 16px; } .hero h1 { font-size: 27px; } .hero-books { height: 200px; }
  .hero-books .cover { width: 120px; } .hero-books .cover:nth-child(2) { width: 136px; }
  .feats { grid-template-columns: 1fr 1fr; gap: 10px; } .feat { padding: 12px; flex-direction: column; gap: 8px; }
  .cta { grid-template-columns: 1fr; padding: 26px 22px; } .cta h2 { font-size: 22px; }
  .cats { grid-template-columns: 1fr 1fr; } .cat { flex-direction: column; align-items: flex-start; padding: 14px; }
  .band { grid-template-columns: 1fr; }
  .books { grid-template-columns: repeat(2, 1fr); gap: 18px 12px; }
  .rail { grid-auto-columns: 150px; }
  .detail { grid-template-columns: 1fr; } .detail .cover { max-width: 220px; margin: 0 auto; }
  .page-t { font-size: 23px; }
  .fsec { grid-template-columns: 1fr; gap: 8px; padding: 14px 0; }
  .paper .probs { grid-template-columns: 1fr; } .reader-page .probs { grid-template-columns: 1fr; } .reader-page { padding: 16px; }
  .paper .ans, .paper .ans.only { grid-template-columns: 1fr; }
  .citem { grid-template-columns: 56px 1fr; } .citem .cover { width: 56px; } .citem-r { grid-column: 1 / -1; flex-direction: row; justify-content: space-between; align-items: center; }
  .form { grid-template-columns: 1fr; } .opt-grid { grid-template-columns: 1fr; }
  .guide-steps { grid-template-columns: 1fr; } .ftr-in { grid-template-columns: 1fr; padding-bottom: 40px; }
  .stepper { max-width: 100%; } .step { min-width: 56px; font-size: 11px; } .step-ln { margin-bottom: 20px; }
  .stat-grid { grid-template-columns: 1fr; }
  .timeline { flex-wrap: wrap; } .tl { flex: 1 1 30%; }
}