/* ========== 页面顶部标题栏 ========== */
.page-top-title {
    position: fixed;
    top: env(safe-area-inset-top);
    left: 50%;
    transform: translateX(-50%);
    width: 100%;
    max-width: 480px;
    font-size: 24px;
    font-weight: 700;
    padding: 12px 0;
    color: var(--text-primary);
    text-align: center;
    z-index: 99;
    background: var(--title-bg);
    backdrop-filter: blur(14px);
    -webkit-backdrop-filter: blur(14px);
    box-shadow: 0 2px 12px rgba(0,0,0,0.06);
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 10px;
}

.theme-toggle-btn {
    position: absolute;
    right: 16px;
    top: 50%;
    transform: translateY(-50%);
    background: var(--glass-hover);
    border: 1px solid var(--input-border);
    border-radius: 8px;
    padding: 5px 12px;
    font-size: 13px;
    font-weight: 600;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--text-primary);
    transition: 0.2s;
    white-space: nowrap;
}

.theme-toggle-btn:active { transform: translateY(-50%) scale(0.9); }

/* ========== 移动端底部导航 ========== */
.tab-bar-wrap {
    position: fixed;
    bottom: calc(24px + env(safe-area-inset-bottom));
    left: 50%;
    transform: translateX(-50%);
    z-index: 100;
}

.tab-bar {
    display: flex;
    flex-direction: row;
    align-items: center;
    justify-content: center;
    background: var(--tab-bg);
    backdrop-filter: blur(14px);
    -webkit-backdrop-filter: blur(14px);
    box-shadow: 0 4px 24px rgba(0,0,0,0.08);
    border: 1px solid var(--glass-border);
    border-radius: 999px;
    padding: 8px 8px;
    gap: 2px;
}

.tab-item {
    padding: 9px 14px;
    font-size: 13px;
    color: var(--tab-inactive);
    transition: all 0.2s ease;
    border-radius: 999px;
    cursor: pointer;
    white-space: nowrap;
    text-align: center;
}

.tab-item.active {
    color: #fff;
    font-weight: 600;
    background: linear-gradient(135deg, var(--primary), var(--primary-light));
    box-shadow: 0 2px 8px rgba(37, 99, 235, 0.3);
}

/* ========== 二级页面 ========== */
.sub-page {
    display: none;
    position: fixed;
    top: 0;
    left: 50%;
    transform: translateX(-50%);
    width: 100%;
    max-width: 480px;
    height: 100%;
    background: linear-gradient(135deg, var(--bg-start) 0%, var(--bg-end) 100%);
    background-color: var(--bg-solid);
    z-index: 200;
    overflow-y: auto;
    -webkit-overflow-scrolling: touch;
    padding: 0 14px calc(20px + env(safe-area-inset-bottom));
}

.sub-page.show {
    display: block;
}

.sub-page-header {
    position: sticky;
    top: 0;
    z-index: 201;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 10px;
    padding: calc(12px + env(safe-area-inset-top)) 14px 12px;
    margin: 0 -14px 0;
    background: var(--title-bg);
    backdrop-filter: blur(14px);
    -webkit-backdrop-filter: blur(14px);
    box-shadow: 0 2px 12px rgba(0,0,0,0.06);
    font-size: 24px;
    font-weight: 700;
    color: var(--text-primary);
}

.sub-page-header .back-btn {
    position: absolute;
    left: 14px;
    top: 50%;
    transform: translateY(-50%);
}

.back-btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 32px;
    height: 32px;
    font-size: 24px;
    line-height: 1;
    color: var(--text-primary);
    cursor: pointer;
    border-radius: 8px;
    -webkit-tap-highlight-color: transparent;
}

.back-btn:active {
    background: var(--input-border);
}

.sub-page-content {
    padding-top: 14px;
}