* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    /* 主题 token 默认值（被 theme.css 的 :root[data-theme] 覆盖） */
    --brand: #0F6CBD;
    --brand-hover: #0B5CA6;
    --brand-soft: #E8F1FA;
    --bg: #F5F6F7;
    --card: #FFFFFF;
    --border: #E0E3E8;
    --text: #1F2733;
    --text-2: #5F6B7A;
    --text-3: #9AA3AF;
    --nav-bg: #FFFFFF;
    --nav-text: #3A4657;
    --nav-soft: #E8F1FA;
    --radius: 6px;
    --shadow-card: 0 1px 2px rgba(16, 32, 48, .06);
    --success: #16A34A;
    --warning: #D97706;
    --danger: #DC2626;

    /* 兼容旧变量名（让 base.css 用户页面自动应用新主题） */
    --primary-color: var(--brand);
    --secondary-color: var(--brand);
    --warning-color: var(--warning);
    --danger-color: var(--danger);
    --info-color: var(--brand);
    --success-color: var(--success);
    --text-color: var(--text);
    --text-light: var(--text-2);
    --bg-color: var(--bg);
    --bg-dark: var(--nav-bg);
    --border-color: var(--border);
    --header-height: 3.75rem;
    --bottom-panel-height: 15rem;
}

body {
    font-family: 'Segoe UI', -apple-system, 'PingFang SC', 'Microsoft YaHei', sans-serif;
    background-color: var(--bg-color);
    color: var(--text-color);
    overflow: hidden;
}

.hidden {
    display: none !important;
}

.btn {
    padding: clamp(0.25rem, 0.3vw, 0.5rem) clamp(0.5rem, 0.7vw, 1rem);
    border: none;
    border-radius: 4px;
    cursor: pointer;
    font-size: clamp(0.75rem, 0.8vw, 0.875rem);
    transition: all 0.3s;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: clamp(0.1875rem, 0.2vw, 0.375rem);
    min-width: clamp(48px, 4vw, 60px);
    min-height: clamp(28px, 2.8vw, 32px);
    white-space: nowrap;
    flex-shrink: 0;
}

.btn:hover {
    opacity: 0.9;
    transform: translateY(-1px);
}

.btn:active {
    transform: translateY(0);
}

.btn-primary {
    background-color: var(--primary-color);
    color: white;
}

.btn-secondary {
    background-color: var(--secondary-color);
    color: white;
}

.btn-warning {
    background-color: var(--warning-color);
    color: white;
}

.btn-danger {
    background-color: var(--danger-color);
    color: white;
}

.btn-info {
    background-color: var(--info-color);
    color: white;
}

.btn-success {
    background-color: var(--success-color);
    color: white;
}

.btn-small {
    padding: clamp(4px, 0.4vw, 6px) clamp(8px, 0.8vw, 12px);
    font-size: clamp(11px, 0.75vw, 13px);
    min-height: clamp(26px, 2.6vw, 34px);
    min-width: auto;
    gap: clamp(2px, 0.2vw, 4px);
    font-weight: 500;
    white-space: nowrap;
    flex-shrink: 0;
    border-radius: 6px;
}

.btn-large {
    padding: 0.75rem 1.5rem;
    font-size: 1rem;
}

.icon {
    font-size: 1rem;
}

.toggle-switch {
    position: relative;
    display: inline-block;
    width: 56px;
    height: 28px;
}

.toggle-switch input {
    opacity: 0;
    width: 0;
    height: 0;
}

.toggle-switch .slider {
    position: absolute;
    cursor: pointer;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background-color: #ccc;
    transition: 0.3s;
    border-radius: 28px;
}

.toggle-switch .slider:before {
    position: absolute;
    content: "";
    height: 20px;
    width: 20px;
    left: 4px;
    bottom: 4px;
    background-color: white;
    transition: 0.3s;
    border-radius: 50%;
    box-shadow: 0 2px 4px rgba(0,0,0,0.2);
}

.toggle-switch input:checked + .slider {
    background-color: var(--brand);
}

.toggle-switch input:checked + .slider:before {
    transform: translateX(28px);
}

@keyframes pulse {
    0%, 100% {
        opacity: 1;
    }
    50% {
        opacity: 0.5;
    }
}

.page-header {
    height: auto;
    min-height: var(--header-height);
    background: var(--bg-dark);
    color: white;
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 0 1.25rem;
    box-shadow: 0 0.125rem 0.625rem rgba(0, 0, 0, 0.1);
    flex-wrap: wrap;
    gap: 0.75rem;
}

.header-left,
.header-right {
    display: flex;
    align-items: center;
    gap: 1.25rem;
    flex-wrap: wrap;
}

.header-left h2 {
    font-size: 1.25rem;
    margin-right: 0.625rem;
}

.user-name,
.class-name {
    background: rgba(255, 255, 255, 0.1);
    padding: 0.25rem 0.75rem;
    border-radius: 4px;
    font-size: 0.875rem;
}

.header-center {
    display: flex;
    align-items: center;
    gap: 10px;
}

.main-content {
    flex: 1;
    display: flex;
    overflow: hidden;
    position: relative;
    min-width: 0;
}