/* 通用底部導航（index / training / me / statistics / gongyi 共用） */
:root {
    --bn-tab-bg: rgba(99, 102, 241, .1);
    --bn-tab-active: linear-gradient(135deg, #6366F1, #4f46e5);
    --bn-text: #475569;
    --bn-text-active: #0f172a;
}

.app-bottom-nav {
    position: fixed;
    left: 0;
    right: 0;
    bottom: 0;
    z-index: 50;
    padding-bottom: env(safe-area-inset-bottom);
    background: linear-gradient(180deg, rgba(255, 255, 255, .72), rgba(255, 255, 255, .96));
    box-shadow: 0 -4px 16px rgba(99, 102, 241, .12);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border-top: 1px solid rgba(99, 102, 241, .1);
}

.app-bottom-nav .tabs {
    max-width: 520px;
    margin: 0 auto;
    height: 64px;
    display: grid;
    grid-template-columns: repeat(5, 1fr);
    gap: 8px;
    padding: 8px 10px;
}

.app-bottom-nav .tab {
    border-radius: 12px;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: 4px;
    color: var(--bn-text);
    text-decoration: none;
    font-size: 11px;
}

.app-bottom-nav .tab i {
    width: 22px;
    height: 22px;
    border-radius: 8px;
    display: grid;
    place-items: center;
    background: var(--bn-tab-bg);
    border: 1px solid rgba(99, 102, 241, .16);
}

.app-bottom-nav .tab i svg,
.app-bottom-nav .tab:not([data-tab="models"]) > svg {
    width: 16px;
    height: 16px;
    fill: var(--bn-text);
}

.app-bottom-nav .tab.active {
    color: var(--bn-text-active);
    font-weight: 700;
}

.app-bottom-nav .tab.active i {
    background: var(--bn-tab-active);
    border-color: transparent;
    box-shadow: 0 4px 12px rgba(99, 102, 241, .35);
}

.app-bottom-nav .tab.active i svg,
.app-bottom-nav .tab.active:not([data-tab="models"]) > svg {
    fill: #fff;
}

/* 中間公益愛心：原版 32px，不加小方框 */
.app-bottom-nav .tab[data-tab="models"] {
    gap: 0;
    justify-content: center;
}

.app-bottom-nav .tab[data-tab="models"] > svg {
    width: 32px;
    height: 32px;
    flex-shrink: 0;
    background: transparent;
    border: none;
    padding: 0;
    box-sizing: content-box;
}

.app-bottom-nav .tab.active[data-tab="models"] > svg {
    background: transparent;
    border: none;
}

.app-bottom-nav .tab.active[data-tab="models"] > svg path {
    fill: #d81e06 !important;
}