/* ===== 底部导航 ===== */
.bottom-nav {
    position: fixed;
    bottom: 0;
    left: 0;
    right: 0;
    background: rgba(15,15,26,0.88);
    backdrop-filter: blur(24px) saturate(180%);
    -webkit-backdrop-filter: blur(24px) saturate(180%);
    border-top: 1px solid var(--border-light);
    display: flex;
    z-index: 50;
    padding-bottom: var(--safe-bottom);
    transition: transform 0.2s ease, background 0.4s var(--ease);
}
[data-theme="light"] .bottom-nav { background: rgba(255,255,255,0.88); }
.nav-item {
    flex: 1;
    display: flex;
    flex-direction: column;
    align-items: center;
    padding: 8px 0 6px;
    cursor: pointer;
    color: var(--text-dim);
    transition: color 0.2s var(--ease);
    -webkit-tap-highlight-color: transparent;
}
.nav-item.active { color: var(--accent); }
.nav-item .ni-icon { font-size: 1.3em; margin-bottom: 2px; transition: transform 0.2s var(--ease-spring); display: flex; align-items: center; justify-content: center; }
.nav-item.active .ni-icon { transform: scale(1.1); }
.nav-svg { width: 22px; height: 22px; }
.logo-icon .nav-svg { width: 20px; height: 20px; }
.chip-svg { width: 14px; height: 14px; vertical-align: -1px; }
.inline-svg { width: 15px; height: 15px; vertical-align: -2px; }
.btn-svg { width: 14px; height: 14px; }
.es-svg { width: 36px; height: 36px; opacity: 0.4; }
.mi-icon .nav-svg { width: 22px; height: 22px; }
.nav-item .ni-label { font-size: 0.65em; font-weight: 700; letter-spacing: 0.3px; }

/* 中间加号 */
.nav-center { flex: 1; display: flex; align-items: center; justify-content: center; }
.nav-plus {
    width: 46px;
    height: 46px;
    border-radius: 50%;
    background: linear-gradient(135deg, var(--accent), var(--accent-dark));
    color: #fff;
    border: none;
    font-size: 1.8em;
    font-weight: 300;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    box-shadow: 0 4px 20px var(--accent-glow);
    transition: transform 0.2s var(--ease-spring);
    margin-top: -20px;
}
.nav-plus:active { transform: scale(0.85); }