/* =====================================================================
 * 43 · 后端架构术语速查 —— 独立设计
 * 视觉原型：终端式检索首屏 + 四层货架 + 三列可展开术语卡 + 双栏对照。
 * 与 41 / 42 的版式完全不同：无侧栏、无衬线、无纸感，等宽字与细网格为主。
 * ===================================================================== */
.p43 {
    --g5c-bg: #f1f4f5;
    --g5c-bg2: #e4eaec;
    --g5c-surface: #ffffff;
    --g5c-surface2: #f6f9f9;
    --g5c-ink: #1c262b;
    --g5c-ink2: #4c5c63;
    --g5c-muted: #8a9aa0;
    --g5c-line: #dde5e7;
    --g5c-line2: #c2d0d3;
    --g5c-accent: #0b7d68;
    --g5c-accent2: #2663a8;
    --g5c-on: #ffffff;
    --g5d-bg: #0d1316;
    --g5d-bg2: #151f23;
    --g5d-surface: #161f24;
    --g5d-surface2: #1c282e;
    --g5d-ink: #e9f1f0;
    --g5d-ink2: #aebfbe;
    --g5d-muted: #7c9291;
    --g5d-line: #29383d;
    --g5d-line2: #3a4c52;
    --g5d-accent: #55d2a8;
    --g5d-accent2: #87b4f0;
    --g5d-on: #0d1316;
    --g5-h: "JetBrains Mono", "SFMono-Regular", Consolas, "Microsoft YaHei", monospace;
    --g5-body: 14.5px;
    --g5-lh: 1.8;
    --g5-r: 10px;
    --flow: #3b82c4; --tolerate: #d08b2c; --data: #8562c4; --observe: #1c9a77;
}
:root[data-theme="dark"] .p43 { --flow: #79b0ec; --tolerate: #e5b76b; --data: #b69bef; --observe: #5fd6ab; }

/* ---------- 首屏 ---------- */
.btc-hero { display: grid; grid-template-columns: 1.15fr .85fr; gap: 30px; padding: 12px 0 28px; }
.btc-kicker { display: flex; gap: 14px; font-family: var(--g5-m); font-size: 10.5px; font-weight: 700; letter-spacing: .14em; color: var(--g5-accent); margin-bottom: 18px; }
.btc-kicker span:last-child { color: var(--g5-muted); }
.btc-hero h1 { font-size: clamp(2.2rem, 4.4vw, 3.3rem); line-height: 1.16; letter-spacing: -.05em; margin: 0 0 18px; }
.btc-hero h1 em { font-style: normal; color: var(--g5-accent); }
.btc-lede { max-width: 600px; font-size: 15.4px; line-height: 1.9; color: var(--g5-ink2); margin-bottom: 22px; }
.btc-lede b { color: var(--g5-ink); }
.btc-search {
    display: flex; align-items: center; gap: 10px; max-width: 620px;
    background: var(--g5-surface); border: 1px solid var(--g5-line2);
    border-radius: var(--g5-r); padding: 8px 9px 8px 15px; box-shadow: var(--g5-shadow);
}
.btc-search > span { font-family: var(--g5-m); font-weight: 800; color: var(--g5-accent); font-size: 15px; }
.btc-search input { flex: 1; min-width: 0; border: 0 !important; background: transparent !important; box-shadow: none !important; font-family: var(--g5-m); font-size: 13.4px; }
.btc-search input:focus { box-shadow: none !important; }
.btc-quick { display: flex; align-items: center; flex-wrap: wrap; gap: 7px; margin-top: 13px; }
.btc-quick > span { font-size: 11.5px; color: var(--g5-muted); }
.btc-quick button {
    border: 1px solid var(--g5-line); border-radius: 6px; background: var(--g5-surface);
    color: var(--g5-ink2); font-family: var(--g5-m); font-size: 11.5px; padding: 4px 10px;
}
.btc-quick button:hover { border-color: var(--g5-accent); color: var(--g5-accent); }
.btc-hero-note { margin-top: 16px; font-size: 12.3px; color: var(--g5-muted); }

/* ---------- 四层货架 ---------- */
.btc-shelf {
    background: var(--g5-surface); border: 1px solid var(--g5-line2);
    border-radius: var(--g5-r); padding: 16px; box-shadow: var(--g5-shadow);
    display: grid; gap: 8px;
}
.btc-shelf-hd { display: flex; align-items: baseline; justify-content: space-between; gap: 8px; margin-bottom: 4px; }
.btc-shelf-hd b { font-family: var(--g5-m); font-size: 11px; letter-spacing: .14em; color: var(--g5-ink); }
.btc-shelf-hd span { font-size: 11px; color: var(--g5-muted); }
.btc-layer {
    display: grid; grid-template-columns: 30px 76px 1fr 10px; align-items: center; gap: 9px;
    text-align: left; border: 1px solid var(--g5-line); border-left: 4px solid var(--flow);
    border-radius: 7px; background: var(--g5-surface2); padding: 10px 12px;
    color: var(--g5-ink); transition: transform .14s, border-color .14s, background .14s;
}
.btc-layer:hover { transform: translateX(3px); background: var(--g5-bg2); }
.btc-layer.is-on { border-color: var(--g5-accent); background: var(--g5-bg2); }
.btc-layer[data-layer="tolerate"] { border-left-color: var(--tolerate); }
.btc-layer[data-layer="data"] { border-left-color: var(--data); }
.btc-layer[data-layer="observe"] { border-left-color: var(--observe); }
.btc-layer i { font-family: var(--g5-m); font-style: normal; font-size: 11px; color: var(--g5-muted); }
.btc-layer b { font-size: 13.4px; }
.btc-layer small { font-size: 11.8px; color: var(--g5-ink2); }
.btc-dot { width: 8px; height: 8px; border-radius: 50%; background: var(--g5-line2); }
.btc-layer.is-on .btc-dot { background: var(--g5-accent); }
.btc-shelf-ft { margin-top: 5px; padding-top: 10px; border-top: 1px dashed var(--g5-line); text-align: right; }
.btc-shelf-ft code { background: transparent; color: var(--g5-muted); font-size: 10.5px; }

/* ---------- 工具栏 ---------- */
.btc-toolbar {
    display: flex; align-items: center; justify-content: space-between; gap: 14px; flex-wrap: wrap;
    padding: 12px 0 18px; border-bottom: 1px solid var(--g5-line); margin-bottom: 22px;
}
.btc-filters { display: flex; flex-wrap: wrap; gap: 7px; }
.btc-filters button {
    border: 1px solid var(--g5-line2); border-radius: 6px; background: var(--g5-surface);
    color: var(--g5-ink2); font-size: 12px; font-weight: 700; padding: 5px 12px;
}
.btc-filters button b { font-family: var(--g5-m); }
.btc-filters button.is-on { background: var(--g5-accent); border-color: var(--g5-accent); color: #fff; }
.btc-filters button#btcReset { background: transparent; border-style: dashed; }
.btc-picked { display: flex; align-items: center; gap: 9px; font-size: 12px; color: var(--g5-muted); }

/* ---------- 术语卡 ---------- */
.btc-cards { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 16px; }
.btc-card {
    display: flex; flex-direction: column; background: var(--g5-surface);
    border: 1px solid var(--g5-line); border-top: 3px solid var(--flow);
    border-radius: var(--g5-r); padding: 17px 17px 15px; box-shadow: var(--g5-shadow);
}
.btc-card[data-layer="tolerate"] { border-top-color: var(--tolerate); }
.btc-card[data-layer="data"] { border-top-color: var(--data); }
.btc-card[data-layer="observe"] { border-top-color: var(--observe); }
.btc-card.is-picked { outline: 2px solid var(--g5-accent); outline-offset: 2px; }
.btc-card-top { display: flex; align-items: flex-start; justify-content: space-between; gap: 8px; }
.btc-card-no { font-family: var(--g5-m); font-size: 10.5px; color: var(--g5-muted); }
.btc-card h3 { font-size: 17.5px; margin: 6px 0 3px; letter-spacing: -.02em; }
.btc-card .btc-alias { font-family: var(--g5-m); font-size: 10.5px; color: var(--g5-accent); word-break: break-all; }
.btc-card .btc-layer-tag {
    align-self: flex-start; font-size: 10.5px; font-weight: 700; padding: 2px 8px;
    border-radius: 4px; background: var(--g5-bg2); color: var(--g5-ink2); margin-top: 9px;
}
.btc-def { font-size: 13px; line-height: 1.85; color: var(--g5-ink2); margin: 13px 0 12px; }
.btc-kv { display: grid; gap: 6px; }
.btc-kv > div { display: grid; grid-template-columns: 52px 1fr; gap: 8px; font-size: 12.2px; line-height: 1.75; }
.btc-kv b { color: var(--g5-muted); font-size: 11px; font-weight: 700; padding-top: 2px; }
.btc-kv span { color: var(--g5-ink2); }
.btc-more { margin-top: 12px; padding-top: 12px; border-top: 1px dashed var(--g5-line); }
.btc-more ul { list-style: none; padding: 0; margin: 0 0 10px; font-size: 12.2px; line-height: 1.8; color: var(--g5-ink2); }
.btc-more li { padding-left: 14px; position: relative; margin-bottom: 5px; }
.btc-more li::before { content: '!'; position: absolute; left: 0; color: var(--g5-warn); font-family: var(--g5-m); font-weight: 800; }
.btc-more h4 { font-size: 11.5px; color: var(--g5-muted); letter-spacing: .06em; margin: 0 0 7px; }
.btc-card-ft { margin-top: auto; padding-top: 14px; display: flex; gap: 8px; }
.btc-card-ft button {
    flex: 1; border: 1px solid var(--g5-line2); border-radius: 6px;
    background: var(--g5-surface2); color: var(--g5-ink2); font-size: 11.8px; font-weight: 700; padding: 6px 8px;
}
.btc-card-ft button:hover { border-color: var(--g5-accent); color: var(--g5-accent); }
.btc-card-ft button.is-on { background: var(--g5-accent); border-color: var(--g5-accent); color: #fff; }
.btc-empty { padding: 30px; text-align: center; color: var(--g5-muted); background: var(--g5-surface); border: 1px dashed var(--g5-line2); border-radius: var(--g5-r); }

/* ---------- 章节通用 ---------- */
.btc-compare, .btc-quiz, .btc-batch {
    margin-top: 32px; padding: 22px 24px 24px; background: var(--g5-surface);
    border: 1px solid var(--g5-line); border-radius: var(--g5-r); box-shadow: var(--g5-shadow);
}
.btc-sec-hd { display: flex; align-items: center; gap: 11px; padding-bottom: 13px; border-bottom: 1px solid var(--g5-line); margin-bottom: 16px; }
.btc-sec-hd > i { font-family: var(--g5-m); font-style: normal; font-size: 11px; font-weight: 700; color: var(--g5-accent); background: var(--g5-bg2); padding: 3px 7px; border-radius: 4px; }
.btc-sec-hd h2 { font-size: 17.5px; }
.btc-sec-hd > span { margin-left: auto; font-size: 11.8px; color: var(--g5-muted); }
.btc-placeholder { font-size: 13.4px; color: var(--g5-muted); line-height: 1.9; margin: 0; }
.btc-compare-body { display: grid; grid-template-columns: 1fr 1fr; gap: 16px; }
.btc-cmp {
    border: 1px solid var(--g5-line); border-radius: 9px; padding: 15px 16px; background: var(--g5-surface2);
}
.btc-cmp h3 { font-size: 15px; margin-bottom: 4px; }
.btc-cmp .btc-alias { font-family: var(--g5-m); font-size: 10.5px; color: var(--g5-accent); }
.btc-cmp dl { margin: 13px 0 0; display: grid; gap: 9px; }
.btc-cmp dt { font-size: 11px; font-weight: 750; color: var(--g5-muted); letter-spacing: .05em; }
.btc-cmp dd { margin: 3px 0 0; font-size: 12.6px; line-height: 1.8; color: var(--g5-ink2); }
.btc-cmp-diff {
    grid-column: 1 / -1; border-left: 3px solid var(--g5-accent2); background: var(--g5-infobg);
    color: var(--g5-info); padding: 11px 14px; border-radius: 0 8px 8px 0; font-size: 12.6px; line-height: 1.85;
}

/* ---------- 场景速配 ---------- */
.btc-quiz-lead { font-size: 12.8px; line-height: 1.85; color: var(--g5-ink2); margin: 0 0 16px; }
.btc-quiz-list { display: grid; gap: 10px; }
.btc-quiz-row {
    display: grid; grid-template-columns: 28px 1fr 190px; align-items: center; gap: 12px;
    padding: 11px 13px; border: 1px solid var(--g5-line); border-radius: 8px; background: var(--g5-surface2);
}
.btc-quiz-row > i { font-family: var(--g5-m); font-style: normal; font-size: 11px; color: var(--g5-muted); }
.btc-quiz-row p { margin: 0; font-size: 12.9px; line-height: 1.75; color: var(--g5-ink2); }
.btc-quiz-row select { font-size: 12.4px; padding: 6px 8px; }
.btc-quiz-row.is-right { border-color: var(--g5-ok); }
.btc-quiz-row.is-wrong { border-color: var(--g5-bad); }
.btc-quiz-out { margin-top: 16px; padding: 13px 15px; border-radius: 8px; background: var(--g5-infobg); color: var(--g5-info); font-size: 12.8px; line-height: 1.9; }

/* ---------- 批量 ---------- */
.btc-batch textarea { font-family: var(--g5-m); font-size: 12.4px; line-height: 1.75; }
.btc-clean { display: flex; align-items: center; flex-wrap: wrap; gap: 9px; margin-top: 12px; padding: 11px; border: 1px dashed var(--g5-line2); border-radius: 8px; background: var(--g5-surface2); }
.btc-clean > b { font-size: 11.8px; color: var(--g5-ink2); }
.g5-check { display: inline-flex; align-items: center; gap: 6px; padding: 4px 9px; border: 1px solid var(--g5-line); border-radius: 5px; background: var(--g5-surface); color: var(--g5-ink2); font-size: 11.5px; font-weight: 650; cursor: pointer; user-select: none; }
.g5-check input { width: 14px; height: 14px; margin: 0; }
.g5-check.is-on { border-color: var(--g5-accent); color: var(--g5-accent); background: var(--g5-bg2); }
#btcPreview { max-width: 100%; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; font-size: 10.8px; }
.btc-table { width: 100%; min-width: 560px; font-size: 12.7px; margin-top: 16px; }
.btc-table th { text-align: left; padding: 9px 10px; font-size: 11px; color: var(--g5-muted); border-bottom: 1px solid var(--g5-line2); }
.btc-table td { padding: 10px; border-bottom: 1px solid var(--g5-line); color: var(--g5-ink2); }
.btc-table tr:last-child td { border-bottom: 0; }
.btc-table .btc-empty-td { text-align: center; color: var(--g5-muted); }

/* ---------- 阅读区 ---------- */
.btc-read { margin-top: 42px; padding: 26px 30px 8px; border-top: 2px solid var(--g5-ink); }
.btc-read h2 { font-size: 21px; margin-bottom: 16px; }
.btc-read p { font-size: 14.1px; line-height: 2.05; color: var(--g5-ink2); margin-bottom: 15px; }
.btc-read b { color: var(--g5-accent); }

@media (max-width: 1000px) {
    .btc-hero { grid-template-columns: 1fr; }
    .btc-cards { grid-template-columns: repeat(2, minmax(0, 1fr)); }
}
@media (max-width: 720px) {
    .btc-cards, .btc-compare-body { grid-template-columns: 1fr; }
    .btc-compare, .btc-quiz, .btc-batch { padding: 16px 14px 18px; }
    .btc-quiz-row { grid-template-columns: 24px 1fr; }
    .btc-quiz-row select { grid-column: 2; }
    .btc-read { padding: 22px 16px 6px; }
}