:root {
  --blue: #2563eb;
  --blue-dark: #1d4ed8;
  --blue-soft: #eff6ff;
  --blue-border: #bfdbfe;
  --ink: #0f172a;
  --text: #334155;
  --muted: #64748b;
  --line: #e2e8f0;
  --canvas: #f8fafc;
  --surface: #ffffff;
}

* { box-sizing: border-box; }
body { margin: 0; background: var(--canvas); color: var(--text); font-family: Pretendard, "Noto Sans KR", system-ui, -apple-system, BlinkMacSystemFont, sans-serif; line-height: 1.55; }
button, select { font: inherit; }
.site-header { height: 64px; display: flex; align-items: center; padding: 0 max(24px, calc((100vw - 1024px) / 2)); background: var(--surface); border-bottom: 1px solid var(--line); }
.brand { color: var(--ink); font-size: 19px; font-weight: 820; letter-spacing: -0.055em; text-decoration: none; }
.brand::before { content: ""; display: inline-block; width: 8px; height: 8px; margin: 0 7px 2px 0; background: var(--blue); border-radius: 50%; vertical-align: middle; }
.auth-trigger { margin-left: auto; padding: 8px 11px; color: var(--text); background: var(--surface); border: 1px solid var(--line); border-radius: 9px; cursor: pointer; font-size: 13px; font-weight: 750; }
.auth-trigger:hover { color: var(--blue-dark); border-color: var(--blue-border); background: var(--blue-soft); }
.login-dialog { width: min(calc(100% - 40px), 390px); padding: 0; color: var(--text); border: 0; border-radius: 20px; box-shadow: 0 24px 64px rgb(15 23 42 / .24); }
.login-dialog::backdrop { background: rgb(15 23 42 / .42); backdrop-filter: blur(3px); }
.auth-checking .page-shell, .login-required .page-shell { visibility: hidden; }
.login-required .dialog-close { display: none; }
.login-dialog-head { display: flex; align-items: flex-start; justify-content: space-between; gap: 14px; padding: 26px 26px 0; }
.dialog-eyebrow { margin: 0 0 5px; color: var(--blue); font-size: 12px; font-weight: 800; }
.login-dialog h2 { font-size: 21px; line-height: 1.35; }
.dialog-close { display: grid; place-items: center; width: 30px; height: 30px; padding: 0; color: var(--muted); background: var(--canvas); border: 0; border-radius: 50%; cursor: pointer; font-size: 23px; line-height: 1; }
.login-dialog-copy { margin: 13px 26px 20px; color: var(--muted); font-size: 14px; line-height: 1.65; }
.social-login-list { display: grid; gap: 9px; padding: 0 26px; }
.social-login { display: flex; align-items: center; justify-content: center; gap: 9px; min-height: 48px; border-radius: 11px; cursor: pointer; font-size: 14px; font-weight: 800; }
.social-login span { display: grid; place-items: center; width: 21px; height: 21px; border-radius: 6px; font-size: 12px; font-weight: 900; }
.kakao-login { color: #191600; background: #fee500; border: 1px solid #fee500; }
.kakao-login span { background: #191600; color: #fee500; }
.naver-login { color: #fff; background: #03c75a; border: 1px solid #03c75a; }
.naver-login span { background: #fff; color: #03c75a; }
.login-message { margin: 16px 26px 25px; color: var(--muted); font-size: 12px; text-align: center; }
.mypage-dialog { width: min(calc(100% - 40px), 560px); max-height: min(760px, calc(100vh - 40px)); padding: 0; overflow: auto; color: var(--text); border: 0; border-radius: 20px; box-shadow: 0 24px 64px rgb(15 23 42 / .24); }
.mypage-dialog::backdrop { background: rgb(15 23 42 / .42); backdrop-filter: blur(3px); }
.mypage-profile { display: flex; align-items: center; gap: 12px; margin: 20px 26px 8px; padding: 16px; background: var(--blue-soft); border-radius: 14px; }
.mypage-avatar { display: grid; place-items: center; width: 36px; height: 36px; color: var(--blue); background: #fff; border-radius: 50%; font-size: 16px; }
.mypage-profile strong { display: block; color: var(--ink); font-size: 16px; }
.mypage-profile p { margin: 2px 0 0; color: var(--muted); font-size: 12px; }
.mypage-section { margin: 24px 26px 0; }
.mypage-section-head { display: flex; align-items: baseline; justify-content: space-between; gap: 10px; margin-bottom: 10px; }
.mypage-section h3 { margin: 0; color: var(--ink); font-size: 15px; }
.mypage-section-head span { color: var(--muted); font-size: 12px; }
.mypage-list { display: grid; gap: 8px; }
.mypage-question { display: grid; grid-template-columns: minmax(0, 1fr) auto; gap: 10px; width: 100%; padding: 13px 14px; color: var(--text); text-align: left; background: var(--surface); border: 1px solid var(--line); border-radius: 12px; cursor: pointer; }
.mypage-question:hover { border-color: var(--blue-border); background: #fbfdff; }
.mypage-question strong { display: block; color: var(--ink); font-size: 13px; line-height: 1.45; }
.mypage-question span { display: block; margin-top: 2px; color: var(--muted); font-size: 12px; }
.mypage-question em { align-self: center; color: var(--blue); font-size: 15px; font-style: normal; }
.mypage-empty { margin: 0; padding: 16px; color: var(--muted); background: var(--canvas); border-radius: 12px; font-size: 13px; }
.mypage-actions { margin: 24px 26px 26px; padding-top: 18px; border-top: 1px solid var(--line); }
.logout-button { padding: 8px 0; color: var(--muted); background: transparent; border: 0; cursor: pointer; font-size: 13px; font-weight: 700; }
.logout-button:hover { color: #dc2626; }
.bookmark-button { margin-left: auto; padding: 5px 8px; color: var(--muted); background: var(--surface); border: 1px solid var(--line); border-radius: 8px; cursor: pointer; font-size: 12px; font-weight: 750; }
.bookmark-button:hover, .bookmark-button.is-bookmarked { color: var(--blue-dark); background: var(--blue-soft); border-color: var(--blue-border); }
.page-shell { width: min(100% - 40px, 960px); margin: 0 auto; padding: 44px 0 104px; }
.eyebrow { margin: 0 0 10px; color: var(--blue); font-weight: 750; font-size: 14px; }
h1 { margin: 0; color: var(--ink); font-size: clamp(30px, 5vw, 42px); line-height: 1.24; letter-spacing: -0.052em; }
h2 { margin: 0; color: var(--ink); font-size: 18px; letter-spacing: -0.035em; }
.lead { max-width: 650px; margin: 14px 0 30px; color: var(--muted); font-size: 17px; letter-spacing: -0.025em; }
.control-block { margin: 28px 0; }
.exam-row { display: flex; align-items: center; justify-content: space-between; gap: 32px; padding: 22px 24px; background: var(--surface); border: 1px solid var(--line); border-radius: 18px; box-shadow: 0 7px 18px rgb(15 23 42 / .025); }
.step-heading { display: flex; align-items: flex-start; gap: 12px; }
.step-number { display: grid; flex: 0 0 auto; place-items: center; width: 25px; height: 25px; color: var(--blue-dark); background: var(--blue-soft); border-radius: 50%; font-size: 12px; font-weight: 800; }
.exam-row-label { display: block; margin-bottom: 2px; color: var(--blue); font-size: 12px; font-weight: 800; }
.exam-row strong { display: block; color: var(--ink); font-size: 17px; letter-spacing: -.025em; }
.exam-row p, .step-heading p { margin: 4px 0 0; color: var(--muted); font-size: 13px; }
.exam-select-wrap { min-width: min(100%, 400px); }
.label, label { display: block; margin-bottom: 2px; color: var(--ink); font-size: 17px; font-weight: 750; letter-spacing: -.025em; }
select { width: min(100%, 360px); padding: 13px 14px; color: var(--ink); background: var(--surface); border: 1px solid var(--line); border-radius: 10px; outline: none; }
.exam-select-wrap select { width: 100%; padding: 13px 42px 13px 14px; font-size: 15px; font-weight: 750; border-width: 1px; border-radius: 12px; }
.exam-select-wrap select:focus { border-color: var(--blue); box-shadow: 0 0 0 3px var(--blue-soft); }
select:focus { border-color: var(--blue); box-shadow: 0 0 0 3px var(--blue-soft); }
.exam-status { margin: 8px 0 0; color: var(--muted); font-size: 13px; }
.exam-status.is-pending { color: #9a3412; }
.chip-row { display: flex; flex-wrap: wrap; gap: 8px; }
.subject-segment { display: flex; gap: 22px; width: 100%; margin: 18px 0 16px; border-bottom: 1px solid var(--line); }
.subject-segment .chip { position: relative; flex: 0 0 auto; padding: 0 0 10px; color: var(--muted); background: transparent; border: 0; border-radius: 0; font-size: 14px; font-weight: 700; }
.subject-segment .chip::after { content: ""; position: absolute; right: 0; bottom: -1px; left: 0; height: 2px; background: transparent; border-radius: 2px; }
.subject-segment .chip[aria-pressed="true"] { color: var(--blue); background: transparent; border: 0; box-shadow: none; }
.subject-segment .chip[aria-pressed="true"]::after { background: var(--blue); }
.subject-chip-row .chip { padding: 10px 14px; font-size: 14px; }
.chip { padding: 9px 13px; color: var(--text); background: var(--surface); border: 1px solid var(--line); border-radius: 999px; cursor: pointer; transition: border-color .15s, background .15s, color .15s; }
.chip:hover { border-color: var(--blue-border); }
.chip[aria-pressed="true"], .type-chip { color: var(--blue-dark); background: var(--blue-soft); border-color: var(--blue-border); font-weight: 700; }
.type-chip { cursor: default; }
.official-source-link { color: var(--blue-dark); font-weight: 700; text-decoration: none; }
.official-source-link:hover { text-decoration: underline; }
.explanation-row small { color: var(--muted); }
.verification-row { border-left: 3px solid var(--blue-border); padding-left: 12px; }
.rationale-flow { display: grid; gap: 12px; margin-top: 10px; }
.rationale-step { display: grid; grid-template-columns: 26px minmax(0, 1fr); gap: 10px; padding: 14px; border: 1px solid var(--line); border-radius: 12px; }
.rationale-answer { background: #f8fbff; border-color: #dbeafe; }
.rationale-distractor { background: #fff; }
.rationale-number { display: grid; place-items: center; width: 24px; height: 24px; color: var(--blue-dark); background: var(--blue-soft); border-radius: 50%; font-size: 12px; font-weight: 800; }
.rationale-label { display: block; margin-bottom: 2px; color: var(--blue); font-size: 11px; font-weight: 800; }
.rationale-step strong { display: block; color: var(--ink); font-size: 14px; }
.rationale-step p { margin: 7px 0 0; color: var(--text); font-size: 14px; line-height: 1.75; }
.rationale-step ul { display: grid; gap: 7px; margin: 9px 0 0; padding: 0; list-style: none; }
.rationale-step li { padding-left: 12px; color: var(--text); font-size: 13px; line-height: 1.65; text-indent: -12px; }
.rationale-step li::before { content: "· "; color: var(--blue); font-weight: 800; }
.rationale-source { margin: 0; color: var(--muted); font-size: 12px; }
.question-image-panel { margin: 16px 0; padding: 16px; border: 1px solid var(--line); border-radius: 12px; background: #f8fbff; }
.question-image-panel > p { margin: 8px 0 12px; color: var(--muted); }
.question-image-viewport { max-height: 560px; overflow: auto; border: 1px solid var(--line); border-radius: 8px; background: #fff; }
.question-image-viewport img { display: block; width: 100%; min-width: 720px; height: auto; }
.math-solution-panel { margin-top: 10px; }
.math-solution-intro { margin: 0 0 12px; color: var(--muted); line-height: 1.65; }
.math-solution-viewport { max-height: 720px; overflow: auto; border: 1px solid var(--line); border-radius: 10px; background: #fff; }
.math-solution-viewport img { display: block; width: 100%; min-width: 680px; height: auto; }
.authored-solution { margin-top: 10px; }
.authored-solution-intro { margin: 0 0 14px; color: var(--muted); line-height: 1.65; }
.ai-explanation-row { border-left: 3px solid var(--blue); padding-left: 12px; background: #f7fbff; }
.ai-explanation-lead { margin: 0 0 12px !important; color: #47617f !important; font-size: 13px !important; line-height: 1.65; }
.solution-block { margin: 18px 0; }
.solution-block h4 { margin: 0 0 10px; color: var(--ink); font-size: 16px; letter-spacing: -.02em; }
.solution-block > p { margin: 0; color: var(--text); line-height: 1.8; }
.solution-overview { padding: 18px 20px; border: 1px solid #cfe2ff; border-radius: 14px; background: linear-gradient(135deg, #eff7ff, #fbfdff); }
.solution-overview h4 { color: var(--blue-dark); }
.solution-conditions { padding: 17px 20px; border: 1px solid #dbe6f4; border-radius: 14px; background: #fff; }
.solution-conditions ul, .solution-tools ul { display: grid; gap: 9px; margin: 0; padding: 0; list-style: none; }
.solution-conditions li { position: relative; padding-left: 16px; color: var(--text); font-size: 14px; line-height: 1.7; }
.solution-conditions li::before { content: ""; position: absolute; top: .65em; left: 0; width: 6px; height: 6px; border-radius: 50%; background: var(--blue); }
.solution-tools { padding: 17px 20px; border: 1px solid #dce9dd; border-radius: 14px; background: #f8fcf8; }
.solution-tools li { display: grid; grid-template-columns: minmax(104px, .35fr) 1fr; gap: 10px; color: var(--text); font-size: 14px; line-height: 1.7; }
.solution-tools b { color: #167047; }
.solution-tools span { color: var(--muted); }
.solution-roadmap { padding: 17px 20px; border: 1px solid var(--line); border-radius: 14px; background: #fff; }
.solution-roadmap ol { display: grid; gap: 8px; margin: 0; padding: 0; list-style: none; }
.solution-roadmap li { color: var(--text); font-size: 14px; line-height: 1.65; }
.solution-roadmap b { color: var(--blue-dark); }
.solution-work { padding-top: 2px; }
.solution-work h4 { margin-bottom: 12px; }
.solution-turning { padding: 18px 20px; border: 1px solid #c9ddff; border-radius: 14px; background: #f3f8ff; }
.solution-turning h4 { color: var(--blue-dark); }
.solution-turning > p { margin-bottom: 14px; font-weight: 650; }
.solution-case-list { display: grid; gap: 10px; }
.solution-case-list > div { padding: 12px 14px; border-radius: 10px; background: #fff; border: 1px solid #dce9fa; }
.solution-case-list strong { display: block; color: var(--ink); font-size: 13px; }
.solution-case-list p { margin: 5px 0 0; color: var(--text); font-size: 14px; line-height: 1.7; }
.solution-verification { padding: 16px 20px; border: 1px solid #dce9dd; border-radius: 14px; background: #f8fcf8; }
.solution-verification h4 { color: #167047; }
.solution-verification small { display: block; margin-top: 10px; color: #3f6753; font-size: 13px; line-height: 1.65; }
.solution-breakthrough { padding: 16px 20px; border: 1px solid #f4d8ab; border-radius: 14px; background: #fffaf1; }
.solution-breakthrough h4 { color: #a14a00; }
.ai-callout { margin: 0 0 14px; padding: 14px 16px; border-radius: 10px; line-height: 1.65; }
.ai-callout strong { display: block; margin-bottom: 4px; color: var(--ink); }
.ai-callout p { margin: 0; color: var(--muted); }
.ai-strategy { background: #edf5ff; border: 1px solid #cfe2ff; }
.ai-mistake { margin-top: 14px; background: #fff8ed; border: 1px solid #f3dcae; }
.ai-diagram { margin: 16px 0; overflow: hidden; border: 1px solid #d8e4f4; border-radius: 12px; background: #fff; }
.ai-diagram-graphic { padding: 10px 12px 0; }
.ai-diagram svg { display: block; width: 100%; height: auto; }
.ai-diagram figcaption { display: grid; gap: 3px; padding: 12px 16px 14px; border-top: 1px solid #e7eef8; color: var(--muted); line-height: 1.6; }
.ai-diagram figcaption strong { color: var(--ink); }
.question-panel, .type-summary { padding: 24px; background: var(--surface); border: 1px solid var(--line); border-radius: 16px; }
.question-panel { margin: 30px 0 16px; border-color: #d9e4f2; box-shadow: 0 10px 24px rgb(15 23 42 / .04); }
.question-heading, .section-heading { display: flex; align-items: flex-start; justify-content: space-between; gap: 16px; }
.question-heading p, .section-heading p { margin: 5px 0 0; color: var(--muted); font-size: 14px; }
.selection-tools { display: flex; align-items: center; gap: 8px; }
.selection-count, .lecture-count { flex: 0 0 auto; padding: 5px 10px; color: var(--blue-dark); background: var(--blue-soft); border-radius: 999px; font-size: 13px; font-weight: 700; }
.clear-selection { padding: 5px 4px; color: var(--muted); background: transparent; border: 0; cursor: pointer; font-size: 12px; font-weight: 700; text-decoration: underline; text-underline-offset: 3px; }
.question-grid { display: grid; grid-template-columns: repeat(10, 1fr); gap: 8px; margin-top: 24px; }
.question-button { position: relative; min-height: 46px; padding: 0; color: var(--text); background: var(--surface); border: 1px solid var(--line); border-radius: 11px; cursor: pointer; font-weight: 750; transition: color .15s, background .15s, border-color .15s, transform .15s; }
.question-button:hover { border-color: var(--blue-border); }
.question-button:focus-visible { outline: 3px solid #93c5fd; outline-offset: 2px; }
.question-button[aria-pressed="true"] { color: #fff; background: var(--blue); border-color: var(--blue); box-shadow: 0 4px 10px rgb(37 99 235 / .22); }
.question-button[aria-pressed="true"]::after { content: "✓"; position: absolute; top: 4px; right: 6px; font-size: 10px; font-weight: 900; }
.question-button:disabled { color: #94a3b8; background: #f1f5f9; cursor: not-allowed; }
.action-bar { position: sticky; z-index: 5; bottom: 16px; display: flex; align-items: center; justify-content: space-between; gap: 16px; padding: 14px 16px; background: rgb(255 255 255 / .92); border: 1px solid var(--line); border-radius: 16px; box-shadow: 0 12px 28px rgb(15 23 42 / .12); backdrop-filter: blur(10px); }
.action-bar strong { color: var(--ink); font-size: 15px; }
.action-bar .form-help { margin: 2px 0 0; text-align: left; font-size: 12px; }
.primary-button { flex: 0 0 auto; min-width: 144px; padding: 13px 18px; color: #fff; background: var(--blue); border: 0; border-radius: 12px; cursor: pointer; font-weight: 800; font-size: 15px; }
.primary-button:hover:not(:disabled) { background: var(--blue-dark); }
.primary-button:disabled { background: #cbd5e1; cursor: not-allowed; }
.form-help { margin: 10px 0 0; color: var(--muted); text-align: center; font-size: 14px; }
.hidden { display: none; }
.back-button { padding: 0; margin: 0 0 24px; color: var(--muted); background: transparent; border: 0; cursor: pointer; font-weight: 700; }
.back-button:hover { color: var(--blue); }
.type-summary { margin: 32px 0 38px; }
.type-summary h2 { margin-bottom: 16px; }
.related-section { margin: 0 0 38px; }
.related-question-list { display: grid; gap: 14px; }
.related-group { padding: 20px; background: var(--surface); border: 1px solid var(--line); border-radius: 16px; }
.related-group h3 { margin: 0 0 14px; color: var(--ink); font-size: 15px; letter-spacing: -0.025em; }
.related-cards { display: grid; grid-template-columns: repeat(3, 1fr); gap: 10px; }
.related-card { min-width: 0; padding: 15px; background: var(--canvas); border: 1px solid var(--line); border-radius: 12px; text-align: left; font: inherit; cursor: pointer; transition: border-color .16s ease, box-shadow .16s ease, transform .16s ease; }
.related-card:hover, .related-card:focus-visible { border-color: var(--blue); box-shadow: 0 8px 18px rgba(35, 97, 224, .12); outline: none; transform: translateY(-2px); }
.related-card strong { display: block; margin: 7px 0 0; color: var(--ink); font-size: 14px; line-height: 1.45; }
.related-number { display: block; color: var(--blue); font-size: 12px; font-weight: 750; }
.related-card .type-badge { font-size: 11px; }
.related-card p, .related-empty { margin: 9px 0 0; color: var(--muted); font-size: 12px; line-height: 1.5; }
.related-open { display: block; margin-top: 13px; color: var(--blue); font-size: 12px; font-weight: 750; }
.related-empty { padding: 20px; background: var(--surface); border: 1px solid var(--line); border-radius: 14px; }
.section-heading { margin-bottom: 16px; }
.step-label { margin: 0 0 5px; color: var(--blue); font-size: 13px; font-weight: 800; }
.explanation-list { display: grid; gap: 12px; margin-bottom: 38px; }
.explanation-card { padding: 22px; background: var(--surface); border: 1px solid var(--line); border-radius: 16px; }
.explanation-card header { display: flex; align-items: center; justify-content: space-between; gap: 12px; margin-bottom: 14px; }
.question-label { color: var(--ink); font-weight: 800; }
.answer-badge { flex: 0 0 auto; padding: 4px 9px; color: var(--blue-dark); background: var(--blue-soft); border-radius: 999px; font-size: 13px; font-weight: 800; }
.type-badge { display: inline-flex; margin-top: 6px; padding: 4px 8px; color: var(--text); background: #f1f5f9; border-radius: 7px; font-size: 12px; font-weight: 700; }
.feature-badge { display: inline-flex; margin: 6px 0 0 5px; padding: 4px 8px; border-radius: 7px; font-size: 12px; font-weight: 700; }
.visual-badge { color: #075985; background: #e0f2fe; }
.rate-badge { color: #9a3412; background: #ffedd5; }
.choice-rate-panel { margin-top: 14px; padding: 14px; background: #f8fafc; border: 1px solid var(--line); border-radius: 10px; }
.explanation-key em { margin-left: 4px; color: var(--muted); font-size: 11px; font-style: normal; font-weight: 500; }
.choice-rate-list, .answer-choice-list { display: flex; flex-wrap: wrap; gap: 7px; margin-top: 8px; }
.choice-rate { display: inline-flex; gap: 6px; align-items: center; padding: 6px 8px; color: var(--text); background: var(--surface); border: 1px solid var(--line); border-radius: 7px; font-size: 12px; }
.choice-rate.is-correct { color: #166534; background: #f0fdf4; border-color: #bbf7d0; }
.answer-choice { min-width: 46px; padding: 8px 10px; color: var(--text); background: var(--surface); border: 1px solid var(--line); border-radius: 8px; cursor: pointer; font-size: 13px; font-weight: 750; }
.answer-choice:hover, .answer-choice.is-selected { color: var(--blue-dark); background: var(--blue-soft); border-color: var(--blue-border); }
.personal-analysis { margin-top: 11px; padding: 12px; border-radius: 9px; font-size: 14px; }
.personal-analysis.incorrect { color: #9a3412; background: #fff7ed; border: 1px solid #fed7aa; }
.personal-analysis.correct { color: #166534; background: #f0fdf4; border: 1px solid #bbf7d0; }
.personal-analysis p, .answer-input-note { margin: 5px 0 0; color: inherit; font-size: 13px; }
.answer-input-note { color: var(--muted); }
.study-plan { margin: 0; padding-left: 20px; color: var(--text); }
.study-plan li + li { margin-top: 8px; }
.explanation-row + .explanation-row { margin-top: 12px; padding-top: 12px; border-top: 1px solid var(--line); }
.explanation-key { display: block; margin-bottom: 3px; color: var(--muted); font-size: 12px; font-weight: 750; }
.explanation-row p { margin: 0; color: var(--text); font-size: 14px; }
.lecture-list { display: grid; gap: 12px; }
.routine-section { margin-top: 38px; }
.routine-list { display: grid; gap: 10px; }
.routine-item { display: flex; align-items: flex-start; gap: 12px; padding: 16px; background: var(--surface); border: 1px solid var(--line); border-radius: 14px; }
.routine-toggle { flex: 0 0 auto; width: 24px; height: 24px; margin: 1px 0 0; padding: 0; color: transparent; background: var(--surface); border: 1.5px solid var(--blue-border); border-radius: 50%; cursor: pointer; }
.routine-item.is-complete { background: #f8fbff; }
.routine-item.is-complete .routine-toggle { color: #fff; background: var(--blue); border-color: var(--blue); }
.routine-item.is-complete strong, .routine-item.is-complete p { text-decoration: line-through; opacity: .62; }
.routine-item strong { display: block; color: var(--ink); font-size: 14px; }
.routine-item p { margin: 3px 0 0; color: var(--muted); font-size: 13px; }
.lecture-card { padding: 22px; background: var(--surface); border: 1px solid var(--line); border-radius: 16px; }
.lecture-role { display: inline-block; margin-bottom: 10px; color: var(--blue-dark); font-size: 13px; font-weight: 800; }
.lecture-card h3 { margin: 0; color: var(--ink); font-size: 18px; letter-spacing: -0.03em; }
.lecture-card p { margin: 8px 0 16px; color: var(--muted); font-size: 14px; }
.lecture-link { display: inline-flex; padding: 9px 12px; color: var(--blue); border: 1px solid var(--blue-border); border-radius: 9px; font-size: 14px; font-weight: 750; text-decoration: none; }
.lecture-link:hover { color: #fff; background: var(--blue); border-color: var(--blue); }
footer { padding: 30px 20px; color: var(--muted); background: var(--surface); border-top: 1px solid var(--line); text-align: center; font-size: 13px; }
@media (max-width: 720px) { .site-header { padding: 0 20px; } .page-shell { width: min(100% - 32px, 760px); padding-top: 36px; } .lead { margin-bottom: 28px; font-size: 16px; } .exam-row { display: block; padding: 18px; } .exam-select-wrap { min-width: 0; margin-top: 14px; } .question-panel, .type-summary, .related-group { padding: 18px; } .question-heading, .section-heading { display: block; } .selection-tools { display: inline-flex; margin-top: 12px; } .question-grid { grid-template-columns: repeat(5, 1fr); } .related-cards { grid-template-columns: 1fr; } .subject-segment { gap: 16px; overflow-x: auto; } .subject-segment .chip { flex: 0 0 auto; } .action-bar { bottom: 10px; align-items: center; padding: 12px; } .action-bar .form-help { display: none; } .primary-button { min-width: 112px; } .solution-overview, .solution-conditions, .solution-tools, .solution-roadmap, .solution-turning, .solution-verification, .solution-breakthrough { padding: 15px 16px; } .solution-tools li { grid-template-columns: 1fr; gap: 2px; } .solution-case-list > div { padding: 11px 12px; } .rationale-step { grid-template-columns: 22px minmax(0, 1fr); gap: 9px; padding: 12px; } .rationale-step p, .solution-block > p, .solution-case-list p { font-size: 13px; line-height: 1.7; } .ai-diagram { margin: 14px -2px; border-radius: 10px; } .ai-diagram-graphic { padding: 7px 5px 0; overflow-x: auto; } .ai-diagram svg { min-width: 460px; } .ai-diagram figcaption { padding: 11px 13px 13px; font-size: 13px; } }