/* ===== 脑筋急转弯 /tool/brain-teaser ===== */

.detail-wrap {
    --bt-pink: #ff6a88;
    --bt-orange: #ff9a56;
    --bt-yellow: #ffd166;
    --bt-mint: #4ecdc4;
    --bt-grad: linear-gradient(135deg, #ff9a56 0%, #ff6a88 100%);
    --bt-grad-soft: linear-gradient(135deg, #fff1e6 0%, #ffe6ef 100%);
}

/* 头部 */
.bt-head { display: flex; gap: 22px; align-items: center; margin-bottom: 28px; }
.bt-head-icon {
    width: 74px; height: 74px; border-radius: 20px; display: grid; place-items: center;
    font-size: 38px; background: var(--bt-grad); color: #fff;
    box-shadow: 0 14px 30px rgba(255, 106, 136, .3);
}
.bt-head-main h1 { margin: 0 0 8px; font-size: 32px; font-weight: 900; letter-spacing: -.02em; color: var(--c-text); }
.bt-head-sub { margin: 0 0 14px; font-size: 15px; line-height: 1.7; color: var(--c-sub); max-width: 64ch; }
.bt-head-badges { display: flex; flex-wrap: wrap; gap: 8px; }

/* 主体 */
.bt-board { margin-bottom: 40px; }
.bt-cats { display: flex; flex-wrap: wrap; gap: 10px; margin-bottom: 18px; }
.bt-cat-btn {
    padding: 10px 16px; border: 1px solid var(--c-border); border-radius: 999px;
    background: var(--c-card); cursor: pointer; font-size: 14px; font-weight: 700; color: var(--c-sub); transition: .15s;
}
.bt-cat-btn:hover { border-color: var(--bt-orange); }
.bt-cat-btn.active { background: var(--bt-grad); color: #fff; border-color: transparent; box-shadow: 0 8px 18px rgba(255, 106, 136, .28); }

/* 翻牌 */
.bt-card { width: 100%; min-height: 240px; perspective: 1200px; cursor: pointer; margin-bottom: 18px; }
.bt-inner { position: relative; width: 100%; min-height: 240px; transform-style: preserve-3d; transition: transform .55s cubic-bezier(.4, 0, .2, 1); }
.bt-card.flipped .bt-inner { transform: rotateY(180deg); }
.bt-face {
    position: absolute; inset: 0; backface-visibility: hidden; -webkit-backface-visibility: hidden;
    display: flex; flex-direction: column; align-items: center; justify-content: center; gap: 14px;
    padding: 30px; border-radius: 22px; text-align: center;
}
.bt-front { background: var(--c-card); border: 1px solid var(--c-border); }
.bt-back { background: var(--bt-grad); color: #fff; transform: rotateY(180deg); box-shadow: 0 18px 40px rgba(255, 106, 136, .3); }
.bt-cat-tag { font-size: 13px; font-weight: 800; color: var(--bt-orange); background: var(--bt-grad-soft); padding: 5px 12px; border-radius: 999px; }
.bt-front .bt-cat-tag { color: var(--bt-pink); }
.bt-q { font-size: 26px; font-weight: 900; line-height: 1.5; color: var(--c-text); max-width: 22ch; }
.bt-a-label { font-size: 14px; font-weight: 800; letter-spacing: .3em; opacity: .9; }
.bt-a { font-size: 28px; font-weight: 900; line-height: 1.5; max-width: 22ch; }
.bt-hint { font-size: 13px; color: var(--c-sub); opacity: .85; }
.bt-back .bt-hint { color: rgba(255, 255, 255, .9); }

/* 进度 */
.bt-progress { text-align: center; font-size: 13px; font-weight: 700; color: var(--c-sub); margin-bottom: 14px; }

/* 导航 */
.bt-nav { display: flex; gap: 10px; margin-bottom: 16px; }
.bt-nav-btn {
    flex: 1; padding: 12px; border: 1px solid var(--c-border); border-radius: 12px;
    background: var(--c-bg); color: var(--c-text); font-size: 14px; font-weight: 700; cursor: pointer; transition: .15s;
}
.bt-nav-btn:hover { border-color: var(--bt-orange); }
.bt-nav-btn.bt-rand { background: var(--bt-grad); color: #fff; border-color: transparent; }

/* 亲子 */
.bt-parent { display: flex; align-items: center; justify-content: space-between; gap: 12px; flex-wrap: wrap; margin-bottom: 14px; }
.bt-right { font-size: 14px; font-weight: 800; color: var(--c-text); }
.bt-guess { padding: 11px 18px; border: 0; border-radius: 12px; background: var(--bt-yellow); color: #6b4f00; font-size: 14px; font-weight: 800; cursor: pointer; box-shadow: 0 8px 18px rgba(255, 209, 102, .4); }
.bt-guess:hover { filter: brightness(1.04); }

.bt-tip { font-size: 13px; line-height: 1.8; color: var(--c-sub); background: var(--c-bg); border: 1px solid var(--c-border); border-left: 4px solid var(--bt-orange); border-radius: 12px; padding: 14px 16px; }
.bt-tip b { color: var(--c-text); }

/* tabs 内容 */
.bt-block-head { font-size: 19px; font-weight: 800; color: var(--c-text); margin: 0 0 16px; }
.bt-feature-chips { display: grid; grid-template-columns: repeat(2, 1fr); gap: 10px 18px; margin-bottom: 26px; }
.bt-feature-chip { display: flex; align-items: center; gap: 8px; font-size: 13.5px; color: var(--c-sub); }
.bt-feature-chip .dot { width: 7px; height: 7px; border-radius: 50%; background: var(--bt-pink); flex-shrink: 0; }
.bt-prose { font-size: 15px; line-height: 1.9; color: var(--c-sub); }
.bt-prose b { color: var(--c-text); }

.bt-cat-list { display: grid; grid-template-columns: repeat(auto-fill, minmax(260px, 1fr)); gap: 12px; }
.bt-cat-item { display: flex; gap: 14px; align-items: center; padding: 16px; border-radius: 16px; background: var(--c-card); border: 1px solid var(--c-border); }
.bt-cat-emoji { font-size: 30px; flex-shrink: 0; }
.bt-cat-item b { display: block; font-size: 15px; color: var(--c-text); margin-bottom: 3px; }
.bt-cat-item small { font-size: 12.5px; color: var(--c-muted); }

.bt-steps { display: flex; flex-direction: column; gap: 12px; }
.bt-step { display: flex; gap: 14px; padding: 14px 16px; border-radius: 14px; background: var(--c-card); border: 1px solid var(--c-border); }
.bt-step-no { flex-shrink: 0; width: 30px; height: 30px; border-radius: 9px; display: grid; place-items: center; font-weight: 800; color: #fff; background: var(--bt-grad); font-size: 14px; }
.bt-step-body { font-size: 14px; color: var(--c-sub); line-height: 1.7; }
.bt-step-body b { color: var(--c-text); }

/* 相关 */
.bt-related { margin-top: 42px; }
.bt-related h2 { font-size: 22px; font-weight: 800; color: var(--c-text); margin: 0 0 16px; }
.bt-rel-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(220px, 1fr)); gap: 14px; }
.bt-rel-item { display: flex; align-items: center; gap: 14px; padding: 16px; border-radius: 16px; background: var(--c-card); border: 1px solid var(--c-border); text-decoration: none; transition: .18s; }
.bt-rel-item:hover { transform: translateY(-2px); border-color: var(--bt-orange); box-shadow: 0 10px 24px rgba(255, 106, 136, .12); }
.bt-rel-icon { width: 46px; height: 46px; border-radius: 12px; display: grid; place-items: center; font-size: 24px; background: var(--c-bg); flex-shrink: 0; }
.bt-rel-body { display: flex; flex-direction: column; gap: 3px; min-width: 0; }
.bt-rel-body b { font-size: 15px; font-weight: 700; color: var(--c-text); }
.bt-rel-body small { font-size: 12px; color: var(--c-muted); }
.bt-rel-go { margin-left: auto; color: var(--bt-pink); font-weight: 800; }

@media (max-width: 720px) {
    .bt-head { flex-direction: column; align-items: flex-start; }
    .bt-head-badges { justify-content: center; }
    .bt-feature-chips { grid-template-columns: 1fr; }
    .bt-q { font-size: 22px; }
    .bt-a { font-size: 24px; }
}