.bhb2{--ink:#17212b;--muted:#64707b;--line:#d7dfe5;--paper:#fff;--soft:#f6f8fa;--accent:#9e2f2f;--accent2:#7e2020;max-width:1100px;margin:32px auto;color:var(--ink);font-family:inherit}.bhb2 *{box-sizing:border-box}.bhb2-hero{max-width:850px}.bhb2-kicker,.bhb2-card-kicker{display:block;color:var(--accent);font-size:.78rem;font-weight:850;letter-spacing:.08em;text-transform:uppercase}.bhb2-hero h2{font-size:clamp(2rem,5vw,3.4rem);line-height:1.05;margin:8px 0 12px}.bhb2-hero p{font-size:1.08rem;line-height:1.65;color:var(--muted)}.bhb2-notice{margin:18px 0 24px;padding:13px 16px;background:#fff5e8;border-left:4px solid #b66c00;border-radius:8px}.bhb2-tabs{display:grid;grid-template-columns:repeat(4,1fr);gap:8px;margin:22px 0}.bhb2-tabs button{min-height:48px;padding:10px;border:1px solid var(--line);border-radius:10px;background:#fff;color:var(--ink);font:inherit;font-weight:750;cursor:pointer}.bhb2-tabs button.is-active{background:var(--ink);color:#fff;border-color:var(--ink)}.bhb2-tab{animation:bhb2fade .2s ease}@keyframes bhb2fade{from{opacity:.3;transform:translateY(5px)}to{opacity:1;transform:none}}.bhb2-progress-wrap{padding:16px 18px;background:#fff;border:1px solid var(--line);border-radius:14px;margin-bottom:18px}.bhb2-progress-meta{display:flex;justify-content:space-between;margin-bottom:8px}.bhb2-progress{height:9px;background:#e9edf0;border-radius:99px;overflow:hidden}.bhb2-progress span{display:block;height:100%;width:17%;background:var(--accent);transition:width .25s}.bhb2-lesson-grid,.bhb2-explore-grid{display:grid;grid-template-columns:minmax(0,1.45fr) minmax(280px,.9fr);gap:22px;align-items:start}.bhb2-mini-form,.bhb2-full-form{background:#fff;border:2px solid #26313b;padding:14px;box-shadow:0 12px 28px rgba(20,30,40,.08)}.bhb2-form-head{display:flex;justify-content:space-between;gap:10px;padding:8px 4px 13px;border-bottom:3px solid #26313b;margin-bottom:4px}.bhb2-row{display:grid;grid-template-columns:1fr 1fr}.bhb2-field,.bhb2-explore-field{width:100%;min-height:82px;padding:12px;border:1px solid #3c4650;background:#fff;text-align:left;color:var(--ink);font:inherit;cursor:pointer}.bhb2-field small,.bhb2-field strong,.bhb2-field span{display:block}.bhb2-field small{font-size:.72rem}.bhb2-field strong{margin:3px 0}.bhb2-field span{color:var(--muted)}.bhb2-field.is-highlighted{position:relative;z-index:2;background:#fff0e8;box-shadow:0 0 0 4px rgba(158,47,47,.28);animation:bhb2pulse 1.2s infinite}@keyframes bhb2pulse{50%{box-shadow:0 0 0 8px rgba(158,47,47,.08)}}.bhb2-card,.bhb2-explain,.bhb2-tool-card{background:#fff;border:1px solid var(--line);border-radius:17px;padding:clamp(20px,4vw,32px);box-shadow:0 12px 28px rgba(20,30,40,.07)}.bhb2-card h3,.bhb2-explain h3,.bhb2-tool-card h3{font-size:1.55rem;margin:8px 0 12px}.bhb2-card p,.bhb2-explain p,.bhb2-tool-card p{line-height:1.65;color:var(--muted)}.bhb2-watch{margin:18px 0;padding:14px;background:var(--soft);border-radius:10px;line-height:1.5}.bhb2-watch strong,.bhb2-watch span{display:block}.bhb2-controls{display:flex;justify-content:space-between;gap:10px;margin-top:24px}.bhb2-primary,.bhb2-secondary{min-height:46px;padding:10px 18px;border-radius:10px;font:inherit;font-weight:800;cursor:pointer}.bhb2-primary{background:var(--accent);border:1px solid var(--accent);color:#fff}.bhb2-primary:hover{background:var(--accent2)}.bhb2-secondary{background:#fff;border:1px solid var(--line);color:var(--ink)}.bhb2-secondary:disabled{opacity:.45;cursor:not-allowed}.bhb2-explore-field{min-height:72px}.bhb2-explore-field:hover,.bhb2-explore-field:focus{outline:none;background:#fff9dc;box-shadow:inset 0 0 0 3px rgba(158,47,47,.2)}.bhb2-hot{background:#fff4f0}.bhb2-explain{position:sticky;top:20px;background:var(--ink);color:#fff}.bhb2-explain p{color:#e9edf0}.bhb2-explain .bhb2-watch{background:rgba(255,255,255,.1)}.bhb2-tool-card{max-width:760px;margin:0 auto}.bhb2-input-grid{display:grid;grid-template-columns:1fr 1fr;gap:16px;margin:22px 0}.bhb2-input-grid label{font-weight:750}.bhb2-money{display:flex;align-items:center;margin-top:8px;border:1px solid #aeb9c2;border-radius:10px;overflow:hidden}.bhb2-money b{padding:12px;background:var(--soft)}.bhb2-money input{width:100%;min-height:48px;border:0;padding:10px;font:inherit}.bhb2-result,.bhb2-quiz-result{margin-top:20px;padding:18px;background:var(--soft);border-radius:12px}.bhb2-result span,.bhb2-result strong{display:block}.bhb2-result strong{font-size:2rem;margin-top:5px}.bhb2-result p{margin-bottom:0}.bhb2-tool-card fieldset{margin:18px 0;padding:17px;border:1px solid var(--line);border-radius:12px}.bhb2-tool-card legend{font-weight:800;padding:0 6px}.bhb2-tool-card fieldset label{display:block;margin:10px 0;font-weight:500}.bhb2-quiz-result.good{background:#edf8f1;color:#155b36}.bhb2-quiz-result.try{background:#fff4e6;color:#744500}.bhb2-footer{margin-top:24px;padding:18px;border-left:5px solid var(--accent);background:var(--soft);line-height:1.6}@media(max-width:800px){.bhb2-tabs{grid-template-columns:1fr 1fr}.bhb2-lesson-grid,.bhb2-explore-grid{grid-template-columns:1fr}.bhb2-explain{position:static;order:-1}}@media(max-width:560px){.bhb2-tabs,.bhb2-row,.bhb2-input-grid{grid-template-columns:1fr}.bhb2-controls{flex-direction:column-reverse}.bhb2-controls button,.bhb2-primary{width:100%}}