:root{--topic-ink:#163a58;--topic-blue:#2d70b7;--topic-red:#d54638;--topic-gold:#e7b544;--topic-paper:#fbf7ef;--topic-white:#fffdf9;--topic-mist:#ebf4fb;--topic-mint:#e9f5ef;--topic-line:#e3d6c1;--topic-muted:#64758a;--topic-shadow:0 16px 38px rgba(22,58,88,.1)}
*{box-sizing:border-box}html{scroll-behavior:smooth}body.topic-page{margin:0;background:var(--topic-paper);color:var(--topic-ink);font-family:ui-sans-serif,-apple-system,BlinkMacSystemFont,"Segoe UI","PingFang SC","Microsoft YaHei",sans-serif;line-height:1.68}.topic-top{height:6px;background:linear-gradient(90deg,var(--topic-red) 0 19%,var(--topic-gold) 19% 34%,var(--topic-blue) 34% 100%)}.topic-wrap{max-width:1440px;margin:auto;padding:0 30px 70px}.topic-mast{display:flex;align-items:center;justify-content:space-between;gap:20px;padding:22px 0;border-bottom:1px solid var(--topic-line)}.topic-brand{color:var(--topic-ink);font-size:15px;font-weight:900;letter-spacing:.09em;text-decoration:none}.topic-brand em{padding:0 6px;color:var(--topic-red);font-style:normal}.topic-back{color:var(--topic-blue);font-size:14px;font-weight:850;text-decoration:none}.topic-back:hover{text-decoration:underline}.topic-layout{display:grid;grid-template-columns:230px minmax(0,1fr);gap:48px}.topic-side{position:sticky;top:18px;align-self:start;padding-top:46px}.topic-side p,.topic-eyebrow{margin:0 0 10px;color:var(--topic-blue);font-size:11px;font-weight:900;letter-spacing:.16em;text-transform:uppercase}.topic-side p::before,.topic-eyebrow::before{display:inline-block;width:31px;height:3px;margin:0 12px 3px 0;background:var(--topic-red);content:""}.topic-side a{display:block;padding:9px 0;border-bottom:1px solid var(--topic-line);color:var(--topic-muted);font-size:13px;font-weight:850;text-decoration:none}.topic-side a:hover{color:var(--topic-red)}.topic-side-note{margin-top:23px;padding:15px;border:1px solid var(--topic-line);border-radius:12px;background:rgba(255,255,255,.56);color:var(--topic-muted);font-size:12px}.topic-main{min-width:0}.topic-hero{padding:66px 0 43px}.topic-hero-grid{display:grid;grid-template-columns:minmax(0,1.18fr) minmax(280px,.82fr);gap:40px;align-items:end}.topic-hero h1{max-width:760px;margin:0 0 19px;font-family:Georgia,"Songti SC",serif;font-size:clamp(40px,5.4vw,74px);line-height:1.04;letter-spacing:-.06em}.topic-hero h1 em,.topic-heading h2 em{color:var(--topic-red);font-style:normal}.topic-intro{max-width:690px;margin:0;color:var(--topic-muted);font-size:16px}.topic-hero-card{padding:25px;border-radius:18px;background:var(--topic-ink);box-shadow:var(--topic-shadow);color:#fff}.topic-hero-card p{margin:0 0 7px;color:#c7d9e8;font-size:13px}.topic-hero-card strong{display:block;font:700 22px/1.28 Georgia,"Songti SC",serif}.topic-stats{display:grid;grid-template-columns:repeat(2,1fr);gap:9px;margin-top:21px}.topic-stat{padding:10px 12px;border:1px solid rgba(255,255,255,.2);border-radius:9px}.topic-stat b{display:block;color:#f3ce77;font:700 24px/1 Georgia,serif}.topic-stat span{color:#d9e6ee;font-size:11px}.topic-section{margin-bottom:63px;scroll-margin-top:20px}.topic-heading{display:flex;align-items:end;justify-content:space-between;gap:25px;margin-bottom:20px}.topic-heading h2{margin:0;font:700 clamp(29px,3.1vw,43px)/1.13 Georgia,"Songti SC",serif;letter-spacing:-.045em}.topic-heading>p{max-width:410px;margin:0;color:var(--topic-muted);font-size:13px}.topic-callout{display:grid;grid-template-columns:auto 1fr;gap:15px;margin:0 0 16px;padding:18px 20px;border:1px solid #ead7ae;border-radius:14px;background:#fff6df}.topic-callout>b{color:var(--topic-red);font:900 28px/1 Georgia,serif}.topic-callout p{margin:0;color:#665d4b;font-size:13px}.topic-grid-2{display:grid;grid-template-columns:repeat(2,1fr);gap:14px}.topic-grid-3{display:grid;grid-template-columns:repeat(3,1fr);gap:12px}.topic-card{padding:19px;border:1px solid var(--topic-line);border-radius:14px;background:var(--topic-white)}.topic-card.mist{border-color:#cbe0ee;background:var(--topic-mist)}.topic-card.mint{border-color:#cde3d6;background:var(--topic-mint)}.topic-card h3{margin:0 0 9px;font:700 22px/1.18 Georgia,"Songti SC",serif}.topic-card p{margin:0;color:var(--topic-muted);font-size:13px}.topic-label{color:var(--topic-blue);font-size:10px;font-weight:900;letter-spacing:.12em;text-transform:uppercase}.topic-ru{color:var(--topic-ink);font-family:Georgia,"Times New Roman",serif;font-size:15px}.topic-formula{display:block;margin-top:11px;padding:10px 11px;border-left:3px solid var(--topic-red);border-radius:0 5px 5px 0;background:#f2f6fa;color:var(--topic-ink);font:14px/1.5 Georgia,"Times New Roman",serif}.topic-mark{font-weight:800;text-decoration-line:underline;text-decoration-color:var(--topic-gold);text-decoration-thickness:3px;text-underline-offset:3px}.topic-table-wrap{overflow:auto;border:1px solid var(--topic-line);border-radius:15px;background:var(--topic-white)}.topic-table{width:100%;min-width:720px;border-collapse:collapse}.topic-table th,.topic-table td{padding:14px 15px;border-bottom:1px solid var(--topic-line);vertical-align:top;text-align:left}.topic-table th{background:#f1f6fb;color:var(--topic-blue);font-size:11px;letter-spacing:.1em;text-transform:uppercase}.topic-table td{color:var(--topic-muted);font-size:13px}.topic-table tr:last-child td{border-bottom:0}.topic-pair{display:grid;grid-template-columns:1fr 1fr;gap:8px;margin-top:11px}.topic-pair span{padding:9px;border:1px solid #d7e1e9;border-radius:5px;background:#fff;color:var(--topic-muted);font-size:11px}.topic-pair .topic-ru{display:block;margin-bottom:3px;font-size:13px}.topic-builder{padding:23px;border:1px solid var(--topic-ink);border-radius:16px;background:var(--topic-ink);color:#fff}.topic-builder h3{margin:0 0 7px;font:700 26px/1.15 Georgia,"Songti SC",serif}.topic-builder p{margin:0;color:#cbdee9;font-size:13px}.topic-output{min-height:118px;margin:17px 0;padding:17px;border:1px solid rgba(255,255,255,.2);border-radius:10px;background:rgba(255,255,255,.08)}.topic-output b{display:block;color:#f3ce77;font:700 22px/1.25 Georgia,"Times New Roman",serif}.topic-output span{display:block;margin-top:7px;color:#d7e6ef;font-size:12px}.topic-buttons{display:grid;grid-template-columns:repeat(3,1fr);gap:7px}.topic-buttons button,.topic-next,.topic-retry{padding:10px;border:1px solid rgba(255,255,255,.34);border-radius:7px;background:transparent;color:#fff;cursor:pointer;font:800 12px/1.2 inherit}.topic-buttons button:hover,.topic-buttons button.active{background:#fff;color:var(--topic-ink)}.topic-quiz{padding:25px;border:1px solid var(--topic-line);border-radius:17px;background:var(--topic-white)}.topic-quiz-progress{color:var(--topic-blue);font-size:11px;font-weight:900;letter-spacing:.12em}.topic-question{margin:10px 0 17px;color:var(--topic-ink);font:700 22px/1.45 Georgia,"Songti SC",serif}.topic-options{display:grid;grid-template-columns:repeat(2,1fr);gap:8px}.topic-option{padding:11px;border:1px solid #ccd8e2;border-radius:8px;background:#fff;color:var(--topic-ink);cursor:pointer;font:750 13px/1.35 inherit;text-align:left}.topic-option:hover:not(:disabled){border-color:var(--topic-blue);background:var(--topic-mist)}.topic-option.good{border-color:#71a384;background:#e5f2e8}.topic-option.bad{border-color:#df968d;background:#fff0ed}.topic-feedback{min-height:24px;margin:14px 0 0;color:var(--topic-muted);font-size:13px}.topic-next,.topic-retry{display:none;margin-top:12px;border:0;background:var(--topic-ink);color:#fff}.topic-footer{padding-top:20px;border-top:1px solid var(--topic-line);color:var(--topic-muted);font-size:13px}
@media(max-width:980px){.topic-layout{grid-template-columns:1fr}.topic-side{position:static;display:flex;gap:9px;overflow:auto;padding-top:17px;white-space:nowrap}.topic-side p,.topic-side-note{display:none}.topic-side a{padding:7px 10px;border:1px solid var(--topic-line);border-radius:999px;background:var(--topic-white)}.topic-hero{padding-top:43px}.topic-hero-grid{grid-template-columns:1fr}.topic-grid-3{grid-template-columns:1fr 1fr}}@media(max-width:650px){.topic-wrap{padding:0 16px 48px}.topic-mast{padding:16px 0}.topic-hero h1{font-size:44px}.topic-heading{display:block}.topic-heading>p{margin-top:10px}.topic-grid-2,.topic-grid-3,.topic-pair,.topic-options{grid-template-columns:1fr}.topic-quiz{padding:19px}}

/* Shared reading system for the expanded B1 curriculum */
body.topic-page{line-height:1.72}
.topic-wrap{max-width:1500px;padding:0 36px 82px}
.topic-mast{position:sticky;top:0;z-index:40;padding:19px 0;background:rgba(251,247,239,.96);backdrop-filter:blur(14px)}
.topic-layout{grid-template-columns:248px minmax(0,1fr);gap:56px}
.topic-side{top:92px;padding-top:40px}
.topic-side a{padding:10px 0;font-size:14px}
.topic-side-note{font-size:13px;line-height:1.65}
.topic-hero{padding:58px 0 48px}
.topic-intro{font-size:17px;line-height:1.75}
.topic-hero-card p,.topic-heading>p,.topic-callout p,.topic-card p,.topic-builder p,.topic-feedback,.topic-footer{font-size:15px}
.topic-stat span{font-size:12px}
.topic-section{margin-bottom:72px}
.topic-card{padding:22px}
.topic-card h3{font-size:23px}
.topic-label,.topic-eyebrow,.topic-quiz-progress{font-size:12px}
.topic-ru{font-size:16px}
.topic-formula{padding:12px 13px;font-size:16px;line-height:1.58}
.topic-table th{font-size:12px}
.topic-table td{font-size:15px;line-height:1.6}
.topic-pair span{font-size:13px}
.topic-pair .topic-ru{font-size:14px}
.topic-option{font-size:15px}
.topic-buttons button,.topic-next,.topic-retry{font-size:14px}
.topic-callout a{color:var(--topic-blue);font-weight:850;text-decoration:underline;text-underline-offset:3px}
@media(max-width:980px){.topic-layout{grid-template-columns:1fr}.topic-side{top:auto}.topic-wrap{padding:0 24px 64px}}
@media(max-width:650px){.topic-wrap{padding:0 16px 52px}.topic-mast{padding:14px 0}.topic-brand{font-size:12px}.topic-back{font-size:13px}.topic-hero{padding:40px 0 36px}.topic-hero h1{font-size:clamp(39px,12vw,50px)}.topic-intro{font-size:16px}.topic-section{margin-bottom:54px}.topic-card{padding:18px}.topic-table td{font-size:14px}}

/* Dense handbook helpers */
.topic-list{margin:12px 0 0;padding-left:1.25em;color:var(--topic-muted);font-size:15px}.topic-list li+li{margin-top:7px}.topic-list .topic-ru{font-size:1em}.topic-card .topic-list{margin-bottom:0}.topic-wrong{color:#a43c34;text-decoration:line-through;text-decoration-thickness:1px}.topic-right{color:#247259;font-weight:800}.topic-note{margin-top:14px;padding:14px 16px;border-left:4px solid var(--topic-blue);border-radius:0 9px 9px 0;background:var(--topic-mist);color:var(--topic-muted);font-size:14px}.topic-note strong{color:var(--topic-ink)}.topic-note a{color:var(--topic-blue);font-weight:850;text-decoration:underline;text-underline-offset:3px}