/* Google Material Design 3 styles */
:root {
    --primary-color: #7331f9;
    --primary-dark: #5a25c4;
    --primary-light: #e8deff;
    --primary-surface: #f3edff;
    --text-primary: #202124;
    --text-secondary: #5f6368;
    --text-tertiary: #80868b;
    --divider: #dadce0;
    --background: #f5f5f5;
    --surface: #ffffff;
    --surface-variant: #f8f9fa;
    --outline: #dadce0;
    --outline-variant: #e8eaed;
    --border-radius-small: 4px;
    --border-radius-medium: 8px;
    --border-radius-large: 12px;
    --elevation-1: 0 1px 2px 0 rgba(60,64,67,.3), 0 1px 3px 1px rgba(60,64,67,.15);
    --elevation-2: 0 1px 2px 0 rgba(60,64,67,.3), 0 2px 6px 2px rgba(60,64,67,.15);
    --elevation-3: 0 4px 8px 3px rgba(60,64,67,.15), 0 1px 3px 0 rgba(60,64,67,.3);
    --elevation-4: 0 6px 10px 4px rgba(60,64,67,.15), 0 2px 3px 0 rgba(60,64,67,.3);
}


/* Navigation */
.navbar {
    box-shadow: var(--elevation-2);
    background-color: var(--primary-color) !important;
    border-bottom: none;
    padding: 12px 0;
    min-height: 64px;
    width: 100%;
    margin: 0;
}

.navbar .container-fluid {
    padding-left: 24px;
    padding-right: 24px;
    max-width: none;
    width: 100%;
}

/* Fix for full-width navbar without horizontal scrollbar */
body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Noto Sans SC', 'Microsoft YaHei', 'PingFang SC', 'Hiragino Sans GB', sans-serif;
    background-color: var(--background);
    color: var(--text-primary);
    font-size: 14px;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    overflow-x: hidden;
}

.container-fluid {
    padding-left: 0;
    padding-right: 0;
}

.navbar .container-fluid {
    padding-left: 24px;
    padding-right: 24px;
}

.navbar-brand {
    font-size: 22px;
    color: white !important;
    font-weight: 500;
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Noto Sans SC', 'Microsoft YaHei', 'PingFang SC', sans-serif;
    letter-spacing: 0;
}

.nav-link {
    color: rgba(255, 255, 255, 0.9) !important;
    font-weight: 400;
    font-size: 14px;
    padding: 8px 16px !important;
    border-radius: var(--border-radius-medium);
    transition: all 0.2s cubic-bezier(0.4, 0, 0.2, 1);
    margin: 0 4px;
}

.nav-link:hover {
    color: white !important;
    background-color: rgba(255, 255, 255, 0.1);
    transform: translateY(-1px);
}

/* Main content */
.container {
    max-width: 1200px;
    padding-left: 24px;
    padding-right: 24px;
}

h1, h2, h3, h4, h5, h6 {
    font-weight: 400;
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Noto Sans SC', 'Microsoft YaHei', 'PingFang SC', sans-serif;
    letter-spacing: 0;
}

.year-section {
    margin-bottom: 48px;
}

.year-section h2 {
    color: var(--text-primary);
    font-size: 32px;
    font-weight: 500;
    margin-bottom: 32px;
    border-bottom: 2px solid var(--outline-variant) !important;
    padding-bottom: 16px;
    letter-spacing: -0.5px;
}

.month-section h3 {
    color: var(--text-secondary);
    font-size: 20px;
    margin-bottom: 20px;
    font-weight: 500;
    letter-spacing: 0;
}

/* Exam cards */
.exam-card {
    background: var(--surface);
    border: 1px solid var(--outline-variant);
    border-radius: var(--border-radius-medium);
    transition: all 0.2s cubic-bezier(0.4, 0, 0.2, 1);
    height: 100%;
    overflow: hidden;
    box-shadow: var(--elevation-1);
    margin-bottom: 2rem; /* 确保卡片之间有足够间距 */
}

.exam-card:hover {
    box-shadow: var(--elevation-3);
    transform: translateY(-3px);
    border-color: var(--primary-color);
}

/* Compact exam cards for level.php */
.exam-card-compact {
    background: var(--surface);
    border: 1px solid var(--outline-variant);
    border-radius: 8px;
    transition: all 0.2s cubic-bezier(0.4, 0, 0.2, 1);
    height: auto;
    overflow: hidden;
    box-shadow: 0 1px 2px rgba(0, 0, 0, 0.05);
    margin-bottom: 0.5rem;
}

.exam-card-compact:hover {
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
    transform: translateY(-1px);
    border-color: var(--primary-color);
}

/* Optimized exam cards for level.php */
.exam-card-optimized {
    background: var(--surface);
    border: 1px solid var(--outline-variant);
    border-radius: 12px;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    height: 100%;
    overflow: hidden;
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.08);
    margin-bottom: 1rem;
}

.exam-card-optimized:hover {
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.15);
    transform: translateY(-2px);
    border-color: var(--primary-color);
}

.exam-card-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 20px 24px;
    gap: 16px;
}

.exam-info {
    display: flex;
    flex-direction: column;
    flex-grow: 1;
    min-width: 0;
}

.exam-title {
    font-size: 16px;
    font-weight: 500;
    color: var(--text-primary);
    margin-bottom: 4px;
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Noto Sans SC', 'Microsoft YaHei', 'PingFang SC', sans-serif;
    letter-spacing: 0;
    line-height: 1.3;
}

.exam-duration {
    font-size: 13px;
    color: var(--text-secondary);
    font-weight: 400;
}

.exam-start-btn {
    font-size: 14px;
    font-weight: 500;
    padding: 10px 20px;
    border-radius: 8px;
    white-space: nowrap;
    flex-shrink: 0;
    min-width: 88px;
}

/* New compact exam cards without excessive middle spacing */
.exam-card-compact-new {
    background: var(--surface);
    border: 1px solid var(--outline-variant);
    border-radius: 12px;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    height: 100%;
    overflow: hidden;
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.08);
    margin-bottom: 1rem;
}

.exam-card-compact-new:hover {
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.15);
    transform: translateY(-2px);
    border-color: var(--primary-color);
}

.exam-card-body {
    display: flex;
    align-items: center;
    padding: 18px 20px;
    gap: 20px;
}

.exam-content-left {
    display: flex;
    flex-direction: column;
    flex: 0 1 auto;
    min-width: 0;
}

.exam-content-right {
    flex: 0 0 auto;
    margin-left: auto;
}

.exam-title-compact {
    font-size: 16px;
    font-weight: 500;
    color: var(--text-primary);
    margin-bottom: 3px;
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Noto Sans SC', 'Microsoft YaHei', 'PingFang SC', sans-serif;
    letter-spacing: 0;
    line-height: 1.3;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

.exam-duration-compact {
    font-size: 13px;
    color: var(--text-secondary);
    font-weight: 400;
    white-space: nowrap;
}

.exam-btn-compact {
    font-size: 14px;
    font-weight: 500;
    padding: 8px 16px;
    border-radius: 8px;
    white-space: nowrap;
    min-width: 76px;
}

/* Ultra tight exam cards - content-sized width */
.exam-card-tight {
    background: var(--surface);
    border: 1px solid var(--outline-variant);
    border-radius: 12px;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    overflow: hidden;
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.08);
    margin-bottom: 1rem;
    display: inline-block;
    width: auto;
    min-width: 280px;
    max-width: 380px;
}

.exam-card-tight:hover {
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.15);
    transform: translateY(-2px);
    border-color: var(--primary-color);
}

.exam-card-inner {
    display: flex;
    align-items: center;
    padding: 16px 18px;
    gap: 12px;
    justify-content: space-between;
}

.exam-info-section {
    display: flex;
    flex-direction: column;
    flex: 1 1 auto;
    min-width: 0;
}

.exam-title-tight {
    font-size: 15px;
    font-weight: 500;
    color: var(--text-primary);
    margin-bottom: 2px;
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Noto Sans SC', 'Microsoft YaHei', 'PingFang SC', sans-serif;
    letter-spacing: 0;
    line-height: 1.3;
    white-space: nowrap;
}

.exam-duration-tight {
    font-size: 12px;
    color: var(--text-secondary);
    font-weight: 400;
    white-space: nowrap;
}

.exam-btn-tight {
    font-size: 13px;
    font-weight: 500;
    padding: 7px 14px;
    border-radius: 7px;
    white-space: nowrap;
    flex-shrink: 0;
}

/* Enhanced exam cards with larger size and adaptive layout */
.exam-card-enhanced {
    background: var(--surface);
    border: 1px solid var(--outline-variant);
    border-radius: 14px;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    overflow: hidden;
    box-shadow: 0 2px 6px rgba(0, 0, 0, 0.08);
    margin-bottom: 1.5rem;
    height: 100%;
}

.exam-card-enhanced:hover {
    box-shadow: 0 6px 16px rgba(0, 0, 0, 0.12);
    transform: translateY(-3px);
    border-color: var(--primary-color);
}

.exam-card-content-flex {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 22px 26px;
    gap: 18px;
    min-height: 80px;
}

.exam-details {
    display: flex;
    flex-direction: column;
    flex: 1 1 auto;
    min-width: 0;
    align-items: flex-start;
    text-align: left;
    padding-left: 8px;
    padding-top: 8px;
    justify-content: flex-end;
}

.exam-title-enhanced {
    font-size: 17px;
    font-weight: 500;
    color: var(--text-primary);
    margin-bottom: 8px;
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Noto Sans SC', 'Microsoft YaHei', 'PingFang SC', sans-serif;
    letter-spacing: 0;
    line-height: 1.4;
    align-self: flex-start;
}

.exam-duration-enhanced {
    font-size: 14px;
    color: var(--text-secondary);
    font-weight: 400;
    line-height: 1.3;
    align-self: flex-start;
    margin-top: 4px;
}

.exam-btn-enhanced {
    font-size: 14px;
    font-weight: 500;
    padding: 10px 18px;
    border-radius: 9px;
    white-space: nowrap;
    flex-shrink: 0;
    min-width: 90px;
    transition: all 0.2s ease;
    align-self: center;
}

.exam-btn-enhanced:hover {
    transform: translateY(-1px);
}

/* Responsive adjustments */
@media (max-width: 768px) {
    .exam-card-content-flex {
        flex-direction: column;
        align-items: stretch;
        gap: 12px;
        padding: 18px 20px;
    }
    
    .exam-details {
        text-align: center;
        align-items: center;
        padding-left: 0;
        padding-top: 0;
        justify-content: center;
    }
    
    .exam-title-enhanced {
        align-self: center;
    }
    
    .exam-duration-enhanced {
        align-self: center;
    }
    
    .exam-btn-enhanced {
        width: 100%;
        min-width: unset;
    }
}

@media (max-width: 576px) {
    .exam-card-content-flex {
        padding: 16px 18px;
    }
    
    .exam-title-enhanced {
        font-size: 16px;
    }
    
    .exam-duration-enhanced {
        font-size: 13px;
    }
}

/* 额外的间距控制 */
.exam-detail-spacing {
    margin-bottom: 3rem !important;
}

/* 下拉菜单样式 */
.navbar .dropdown-menu {
    background-color: white !important;
    border: 1px solid var(--outline-variant) !important;
    border-radius: 10px !important;
    box-shadow: var(--elevation-2) !important;
    padding: 0 !important;
    opacity: 0 !important;
    visibility: hidden !important;
    transform: translateY(-12px) !important;
    transition: all 0.5s cubic-bezier(0.4, 0, 0.2, 1) !important;
    min-width: 160px !important;
    position: absolute !important;
    overflow: hidden !important;
}

.navbar .nav-item.dropdown:hover .dropdown-menu,
.navbar .dropdown:hover .dropdown-menu {
    opacity: 1 !important;
    visibility: visible !important;
    transform: translateY(0) !important;
    display: block !important;
}

.navbar .dropdown-menu .dropdown-item,
.navbar .nav-item .dropdown-menu .dropdown-item {
    color: var(--text-primary) !important;
    padding: 12px 16px !important;
    font-size: 14px !important;
    font-weight: 400 !important;
    transition: all 0.2s ease !important;
    border-radius: 0 !important;
    margin: 0 !important;
    text-decoration: none !important;
    background-color: transparent !important;
    display: block !important;
    width: 100% !important;
}

.navbar .dropdown-menu .dropdown-item:hover,
.navbar .nav-item .dropdown-menu .dropdown-item:hover {
    background-color: var(--primary-surface) !important;
    color: var(--primary-color) !important;
    font-weight: 500 !important;
    text-decoration: none !important;
    transform: none !important;
}

.navbar .dropdown-menu .dropdown-item.active,
.navbar .nav-item .dropdown-menu .dropdown-item.active {
    background-color: var(--primary-color) !important;
    color: white !important;
    font-weight: 500 !important;
    box-shadow: 0 2px 4px rgba(115, 49, 249, 0.3) !important;
}

.navbar .dropdown-menu .dropdown-item.active:hover,
.navbar .nav-item .dropdown-menu .dropdown-item.active:hover {
    background-color: var(--primary-dark) !important;
    color: white !important;
    transform: none !important;
}

/* 第一个和最后一个下拉菜单项的圆角处理 */
.navbar .dropdown-menu .dropdown-item:first-child,
.navbar .nav-item .dropdown-menu .dropdown-item:first-child {
    border-top-left-radius: 10px !important;
    border-top-right-radius: 10px !important;
}

.navbar .dropdown-menu .dropdown-item:last-child,
.navbar .nav-item .dropdown-menu .dropdown-item:last-child {
    border-bottom-left-radius: 10px !important;
    border-bottom-right-radius: 10px !important;
}

/* 确保第一个和最后一个项目的背景色完全填充 */
.navbar .dropdown-menu .dropdown-item:first-child:hover,
.navbar .nav-item .dropdown-menu .dropdown-item:first-child:hover,
.navbar .dropdown-menu .dropdown-item:first-child.active,
.navbar .nav-item .dropdown-menu .dropdown-item:first-child.active {
    border-top-left-radius: 10px !important;
    border-top-right-radius: 10px !important;
}

.navbar .dropdown-menu .dropdown-item:last-child:hover,
.navbar .nav-item .dropdown-menu .dropdown-item:last-child:hover,
.navbar .dropdown-menu .dropdown-item:last-child.active,
.navbar .nav-item .dropdown-menu .dropdown-item:last-child.active {
    border-bottom-left-radius: 10px !important;
    border-bottom-right-radius: 10px !important;
}

.navbar .dropdown-toggle::after {
    margin-left: 0.5em !important;
    transition: transform 0.5s ease !important;
}

.navbar .nav-item.dropdown:hover .dropdown-toggle::after,
.navbar .dropdown:hover .dropdown-toggle::after {
    transform: rotate(180deg) !important;
}

/* 首页等级圆圈 */
.level-circle {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    width: 80px;
    height: 80px;
    background: linear-gradient(135deg, var(--primary-color), var(--primary-dark));
    border-radius: 50%;
    text-decoration: none;
    color: white;
    transition: all 0.3s ease;
    box-shadow: var(--elevation-1);
}

.level-circle:hover {
    transform: translateY(-3px);
    box-shadow: var(--elevation-2);
    color: white;
    text-decoration: none;
}

.level-circle span {
    font-size: 20px;
    font-weight: 700;
    line-height: 1;
}

.level-circle small {
    font-size: 10px;
    font-weight: 400;
    opacity: 0.9;
    margin-top: 2px;
}

/* 水平等级选择布局 */
.level-selection-container {
    display: flex;
    justify-content: center;
    width: 100%;
}

.level-cards-horizontal {
    display: flex;
    flex-direction: column;
    gap: 16px;
    max-width: 900px;
    width: 100%;
}

.level-card-horizontal {
    background: var(--surface);
    border: 1px solid var(--outline-variant);
    border-radius: 12px;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    overflow: hidden;
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.08);
}

.level-card-horizontal:hover {
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.12);
    transform: translateY(-2px);
    border-color: var(--primary-color);
}

.level-content {
    display: flex;
    align-items: center;
    padding: 20px 24px;
    gap: 20px;
}

.level-badge-horizontal {
    width: 50px;
    height: 50px;
    background: linear-gradient(135deg, var(--primary-color), var(--primary-dark));
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    flex-shrink: 0;
}

.level-badge-horizontal span {
    color: white;
    font-weight: 700;
    font-size: 18px;
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Noto Sans SC', 'Microsoft YaHei', 'PingFang SC', sans-serif;
}

.level-info {
    flex: 1;
    min-width: 0;
}

.level-title {
    font-size: 18px;
    font-weight: 500;
    color: var(--text-primary);
    margin-bottom: 4px;
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Noto Sans SC', 'Microsoft YaHei', 'PingFang SC', sans-serif;
}

.level-desc {
    font-size: 14px;
    color: var(--text-secondary);
    margin-bottom: 6px;
    line-height: 1.4;
}

.level-details {
    font-size: 12px;
    color: var(--text-secondary);
    font-weight: 400;
}

.level-btn {
    font-size: 14px;
    font-weight: 500;
    padding: 10px 20px;
    border-radius: 8px;
    white-space: nowrap;
    flex-shrink: 0;
    min-width: 100px;
}

/* 响应式设计 */
@media (max-width: 768px) {
    .level-content {
        flex-direction: column;
        text-align: center;
        gap: 16px;
        padding: 18px 20px;
    }
    
    .level-info {
        text-align: center;
    }
    
    .level-btn {
        width: 100%;
        min-width: unset;
    }
}

@media (max-width: 576px) {
    .level-cards-horizontal {
        gap: 12px;
    }
    
    .level-content {
        padding: 16px 18px;
        gap: 12px;
    }
    
    .level-badge-horizontal {
        width: 45px;
        height: 45px;
    }
    
    .level-badge-horizontal span {
        font-size: 16px;
    }
    
    .level-title {
        font-size: 16px;
    }
}

/* 新的等级选择网格布局 */
.level-grid-container {
    display: flex;
    justify-content: center;
    width: 100%;
}

.level-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
    gap: 28px;
    max-width: 1400px;
    width: 100%;
}

.level-card-new {
    background: var(--surface);
    border: 1px solid var(--outline-variant);
    border-radius: 16px;
    overflow: hidden;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.06);
    position: relative;
}

.level-card-new:hover {
    transform: translateY(-4px);
    box-shadow: 0 8px 24px rgba(115, 49, 249, 0.15);
    border-color: var(--primary-color); /* 主题紫色 */
}

/* 卡片悬停时按钮效果 */
.level-card-new:hover .level-btn-new {
    box-shadow: 0 4px 12px rgba(115, 49, 249, 0.25);
}

.level-card-header {
    display: flex;
    align-items: flex-start;
    padding: 28px 28px 20px;
    gap: 20px;
}

.level-badge-new {
    display: none; /* 隐藏等级徽章 */
}

.level-badge-new span {
    color: white;
    font-weight: 700;
    font-size: 24px;
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Noto Sans SC', 'Microsoft YaHei', 'PingFang SC', sans-serif;
}

.level-title-new {
    flex: 1;
    min-width: 0;
    width: 100%;
}

.level-title-new h5 {
    font-size: 24px;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 8px;
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Noto Sans SC', 'Microsoft YaHei', 'PingFang SC', sans-serif;
}

.level-title-new p {
    font-size: 16px;
    color: var(--text-secondary);
    margin-bottom: 0;
    line-height: 1.6;
}

.level-card-body {
    padding: 0 28px 28px;
}

.level-stats {
    display: flex;
    gap: 28px;
    margin-bottom: 24px;
    padding: 20px 0;
    border-top: 1px solid var(--outline-variant);
}

.stat-item {
    display: flex;
    flex-direction: column;
    align-items: center;
    flex: 1;
}

.stat-number {
    font-size: 28px;
    font-weight: 700;
    color: #000000; /* 黑色 */
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Noto Sans SC', 'Microsoft YaHei', 'PingFang SC', sans-serif;
    line-height: 1;
}

.stat-label {
    font-size: 13px;
    color: var(--text-secondary);
    font-weight: 500;
    margin-top: 5px;
}

.level-btn-new {
    width: 100%;
    padding: 14px 24px;
    font-size: 16px;
    font-weight: 500;
    border-radius: 10px;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    transition: all 0.2s ease;
    /* 主题紫色按钮 */
    background-color: var(--primary-color) !important;
    border-color: var(--primary-color) !important;
    color: white !important;
}

.level-btn-new:hover {
    transform: translateY(-1px);
    /* 紫色hover效果 */
    background-color: var(--primary-dark) !important;
    border-color: var(--primary-dark) !important;
    box-shadow: 0 4px 16px rgba(115, 49, 249, 0.35);
    color: white !important;
}

.level-btn-new i {
    transition: transform 0.2s ease;
    font-size: 14px;
}

.level-btn-new:hover i {
    transform: translateX(2px);
}

/* 响应式网格布局 */
@media (max-width: 1024px) {
    .level-grid {
        grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
        gap: 24px;
    }
}

@media (max-width: 768px) {
    .level-grid {
        grid-template-columns: 1fr;
        gap: 20px;
        max-width: 500px;
    }
    
    .level-card-header {
        padding: 24px 24px 16px;
        gap: 16px;
    }
    
    .level-badge-new {
        display: none; /* 移动端也隐藏徽章 */
    }
    
    .level-title-new h5 {
        font-size: 21px;
    }
    
    .level-title-new p {
        font-size: 15px;
    }
    
    .level-card-body {
        padding: 0 24px 24px;
    }
    
    .level-stats {
        gap: 20px;
        margin-bottom: 20px;
    }
}

@media (max-width: 576px) {
    .level-stats {
        flex-direction: column;
        gap: 12px;
    }
    
    .stat-item {
        flex-direction: row;
        justify-content: space-between;
        align-items: center;
    }
    
    .stat-number {
        font-size: 24px;
    }
}

.exam-detail-spacing:last-child {
    margin-bottom: 2rem !important;
}

/* 返回顶部按钮 */
.back-to-top {
    position: fixed;
    bottom: 30px;
    right: 30px;
    width: 50px;
    height: 50px;
    background-color: #475569;
    color: white;
    border: none;
    border-radius: 50%;
    display: none;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    transition: all 0.3s ease;
    box-shadow: 0 4px 12px rgba(71, 85, 105, 0.3);
    z-index: 1000;
    font-size: 18px;
}

.back-to-top:hover {
    background-color: #334155;
    transform: translateY(-2px);
    box-shadow: 0 6px 16px rgba(71, 85, 105, 0.4);
    color: white;
}

.back-to-top.show {
    display: flex;
}

.back-to-top i {
    transition: transform 0.2s ease;
}

.back-to-top:hover i {
    transform: translateY(-1px);
}

/* 题目导航网格 */
.question-nav-grid {
    display: flex;
    flex-wrap: wrap;
    gap: 2px;
    align-items: flex-start;
}

.section-nav {
    border-left: 3px solid var(--outline-variant);
    padding-left: 12px;
}

.section-nav .badge {
    font-weight: 500;
}

.question-nav-btn {
    transition: all 0.2s ease;
}

.question-nav-btn:hover {
    transform: translateY(-1px);
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
}

.question-nav-btn.answered {
    background-color: var(--primary-color) !important;
    border-color: var(--primary-color) !important;
    color: white !important;
}

.question-nav-btn.marked {
    background-color: #fbbf24 !important;
    border-color: #fbbf24 !important;
    color: white !important;
}

.question-nav-btn.current {
    background-color: var(--primary-dark) !important;
    border-color: var(--primary-dark) !important;
    color: white !important;
    transform: scale(1.1);
}

/* 子分类badge样式 */
.subsection-label .badge {
    font-weight: 500;
    letter-spacing: 0.02em;
    border-radius: 6px;
    transition: all 0.2s ease;
}

.subsection-label .badge.bg-dark {
    background-color: #495057 !important;
}

.subsection-label .badge.bg-secondary {
    background-color: #6c757d !important;
}

.subsection-label .badge.bg-info {
    background-color: #0dcaf0 !important;
    color: #000 !important;
}

.subsection-label .badge.bg-light {
    background-color: #f8f9fa !important;
    border: 1px solid #dee2e6;
}

.subsection-label .badge.bg-warning {
    background-color: #ffc107 !important;
    border: 1px solid #ffca2c;
}

/* 考试题目内容样式优化 */
.question-text {
    font-size: 18px !important;
    line-height: 1.6 !important;
    font-weight: 500 !important;
    color: var(--text-primary) !important;
    margin-bottom: 1rem !important;
}

.question-content {
    font-size: 18px !important;
    line-height: 1.7 !important;
    color: var(--text-primary) !important;
    margin-bottom: 1.5rem !important;
    font-weight: 500 !important;
}

/* 题目编号和标签样式 */
.question-number {
    font-size: 15px !important;
    font-weight: 500 !important;
    color: var(--text-primary) !important;
}

/* 选项样式优化 */
.answer-option {
    margin-bottom: 0.8rem !important;
}

.answer-option label {
    font-size: 16px !important;
    line-height: 1.6 !important;
    color: var(--text-primary) !important;
    cursor: pointer !important;
    padding: 10px 14px !important;
    border-radius: 6px !important;
    transition: all 0.2s ease !important;
    display: block !important;
    margin: 0 !important;
    font-weight: 400 !important;
}

.answer-option label:hover {
    background-color: var(--primary-surface) !important;
}

.answer-option input[type="radio"]:checked + label {
    background-color: var(--primary-color) !important;
    color: white !important;
    font-weight: 500 !important;
}

.exam-card .card-body {
    padding: 20px;
}

.exam-card .card-title {
    font-size: 16px;
    font-weight: 500;
    color: var(--text-primary);
    margin-bottom: 8px;
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Noto Sans SC', 'Microsoft YaHei', 'PingFang SC', sans-serif;
    letter-spacing: 0;
}

.exam-card .card-text {
    font-size: 14px;
    color: var(--text-secondary);
    margin-bottom: 16px;
    line-height: 1.4;
}

/* Buttons */
.btn-primary {
    background-color: var(--primary-color);
    border-color: var(--primary-color);
    border-radius: var(--border-radius-large);
    font-weight: 500;
    font-size: 14px;
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Noto Sans SC', 'Microsoft YaHei', 'PingFang SC', sans-serif;
    text-transform: none;
    padding: 10px 24px;
    letter-spacing: 0.25px;
    transition: all 0.2s cubic-bezier(0.4, 0, 0.2, 1);
    border: none;
    box-shadow: none;
}

.btn-primary:hover {
    background-color: var(--primary-dark);
    box-shadow: var(--elevation-1);
    transform: translateY(-1px);
}

.btn-primary:focus {
    background-color: var(--primary-dark);
    box-shadow: 0 0 0 4px rgba(115, 49, 249, 0.12);
    outline: none;
}

.btn-primary:active {
    transform: translateY(0);
    box-shadow: none;
}

.btn-secondary {
    background-color: transparent;
    border: 1px solid var(--outline);
    color: var(--primary-color);
    border-radius: var(--border-radius-large);
    font-weight: 500;
    font-size: 14px;
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Noto Sans SC', 'Microsoft YaHei', 'PingFang SC', sans-serif;
    text-transform: none;
    padding: 10px 24px;
    letter-spacing: 0.25px;
    transition: all 0.2s cubic-bezier(0.4, 0, 0.2, 1);
}

.btn-secondary:hover {
    background-color: var(--primary-surface);
    border-color: var(--primary-color);
    color: var(--primary-color);
}

.btn-outline-primary {
    background-color: transparent;
    border: 1px solid var(--outline);
    color: var(--primary-color);
    border-radius: var(--border-radius-large);
    font-weight: 500;
    font-size: 14px;
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Noto Sans SC', 'Microsoft YaHei', 'PingFang SC', sans-serif;
    text-transform: none;
    padding: 10px 24px;
    letter-spacing: 0.25px;
    transition: all 0.2s cubic-bezier(0.4, 0, 0.2, 1);
}

.btn-outline-primary:hover {
    background-color: var(--primary-surface);
    border-color: var(--primary-color);
    color: var(--primary-color);
}

.btn-sm {
    padding: 6px 16px;
    font-size: 14px;
}

.btn-lg {
    padding: 12px 32px;
    font-size: 16px;
}

/* Footer */
footer {
    position: relative;
    overflow: hidden;
    padding: 4rem 0 !important;
}

footer::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: linear-gradient(135deg, #f8f9fa 0%, #e9ecef 100%);
    z-index: -1;
}

footer .container {
    max-width: 1400px;
}

/* 页脚主标题样式 */
footer h5 {
    position: relative;
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Noto Sans SC', 'Microsoft YaHei', 'PingFang SC', sans-serif;
    font-size: 1.5rem !important;
    font-weight: 600 !important;
    margin-bottom: 1.5rem !important;
    letter-spacing: -0.02em;
}

footer h5::after {
    content: '';
    position: absolute;
    bottom: -12px;
    left: 0;
    width: 50px;
    height: 4px;
    background: linear-gradient(90deg, var(--primary-color), var(--primary-dark));
    border-radius: 2px;
}

/* 页脚副标题样式 */
footer h6 {
    position: relative;
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Noto Sans SC', 'Microsoft YaHei', 'PingFang SC', sans-serif;
    font-size: 1.1rem !important;
    font-weight: 600 !important;
    margin-bottom: 1.25rem !important;
    letter-spacing: -0.01em;
}

/* 页脚描述文字 */
footer p {
    font-size: 1rem !important;
    line-height: 1.8 !important;
    color: #6c757d !important;
    margin-bottom: 1.5rem !important;
}

/* 页脚链接样式 */
footer a {
    font-size: 0.95rem;
}

footer a:hover {
    color: var(--primary-color) !important;
    text-decoration: none !important;
}

/* 社交媒体图标 */
footer .fab {
    font-size: 24px !important;
}

footer a:hover .fab {
    color: var(--primary-color) !important;
}

/* 页脚列表样式 */
footer ul {
    padding-left: 0;
}

footer ul li {
    margin-bottom: 0.75rem !important;
}

footer ul li a {
    display: inline-block;
}

/* 备案信息区域 */
footer .border-top {
    background: transparent;
    border-radius: 8px;
    margin: 0 -15px;
    margin-top: 3rem !important;
    padding: 2rem 15px 0 15px !important;
}

footer .border-top a,
footer .border-top .small {
    font-size: 0.9rem !important;
}

footer .border-top i {
    font-size: 1rem;
}

/* 移动端页脚优化 */
@media (max-width: 768px) {
    footer {
        padding: 3rem 0 !important;
    }
    
    footer .col-6 {
        margin-bottom: 2.5rem;
    }
    
    footer h5 {
        font-size: 1.3rem !important;
        margin-bottom: 1.25rem !important;
    }
    
    footer h5::after {
        width: 40px;
        height: 3px;
        bottom: -10px;
    }
    
    footer h6 {
        font-size: 1rem !important;
        margin-bottom: 1rem !important;
    }
    
    footer p {
        font-size: 0.95rem !important;
        margin-bottom: 1.25rem !important;
    }
    
    footer ul li {
        margin-bottom: 0.6rem !important;
    }
    
    footer .border-top {
        margin: 0;
        margin-top: 2rem !important;
        padding: 1.5rem 0 0 0 !important;
    }
}

@media (max-width: 576px) {
    footer {
        padding: 2.5rem 0 !important;
    }
    
    footer h5 {
        font-size: 1.2rem !important;
    }
    
    footer h6 {
        font-size: 0.95rem !important;
    }
    
    footer p {
        font-size: 0.9rem !important;
    }
    
    footer .d-flex.gap-3 {
        flex-direction: column !important;
        gap: 1rem !important;
        align-items: center !important;
    }
    
    footer .col-md-6 {
        text-align: center !important;
    }
    
    footer .fab {
        font-size: 22px !important;
    }
}

/* Responsive design */
@media (max-width: 768px) {
    .container {
        padding-left: 1rem;
        padding-right: 1rem;
    }
    
    .year-section h2 {
        font-size: 1.125rem;
    }
    
    .exam-card .card-body {
        padding: 1rem;
    }
    
    /* 首页 Hero Section 移动端优化 */
    .container .row.justify-content-center h1 {
        font-size: 2.5rem !important;
    }
    
    .container .row.justify-content-center h2 {
        font-size: 1.5rem !important;
    }
    
    .container .row.justify-content-center p.lead {
        font-size: 1rem !important;
    }
}

@media (max-width: 576px) {
    /* 超小屏幕首页优化 */
    .container .row.justify-content-center h1 {
        font-size: 2rem !important;
    }
    
    .container .row.justify-content-center h2 {
        font-size: 1.25rem !important;
    }
    
    .container .row.justify-content-center p.lead {
        font-size: 0.95rem !important;
    }
}

/* 首页 Hero Section 增强效果 */
.container .row.justify-content-center h1 {
    text-shadow: 0 2px 10px rgba(115, 49, 249, 0.15);
}

/* Form elements */
.form-control {
    border: 1px solid var(--divider);
    border-radius: var(--border-radius);
    padding: 0.75rem;
    font-size: 1rem;
    transition: border-color 0.2s ease;
}

.form-control:focus {
    border-color: var(--primary-color);
    box-shadow: 0 0 0 0.2rem rgba(25, 118, 210, 0.25);
}

/* Progress bar */
.progress {
    height: 4px;
    background-color: var(--divider);
    border-radius: 2px;
}

.progress-bar {
    background-color: var(--primary-color);
}

/* Alert styles */
.alert {
    border: none;
    border-radius: var(--border-radius);
}

.alert-success {
    background-color: #e8f5e8;
    color: #2e7d32;
}

.alert-danger {
    background-color: #ffebee;
    color: #c62828;
}

.alert-warning {
    background-color: #fff8e1;
    color: #f57c00;
}

.alert-info {
    background-color: var(--primary-light);
    color: var(--primary-dark);
}

/* Fixed header for exam page */
.exam-header {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    background-color: var(--primary-color);
    border-bottom: none;
    box-shadow: var(--elevation-2);
    color: white;
}

.exam-content {
    margin-top: 120px; /* 为固定头部留出空间 */
    padding-top: 24px;
}

/* Timer display */
.timer-display {
    background-color: var(--surface-variant);
    border: 1px solid var(--outline-variant);
    border-radius: var(--border-radius-medium);
    padding: 12px 16px;
    text-align: center;
    min-width: 120px;
}

.timer-display .time {
    font-size: 18px;
    font-weight: 500;
    color: var(--primary-color);
    font-family: ui-monospace, 'Cascadia Code', 'Consolas', 'Monaco', monospace;
    letter-spacing: 0.5px;
}

/* Question styles */
.question-card {
    background: var(--surface);
    border: 1px solid var(--outline-variant);
    border-radius: var(--border-radius-large);
    padding: 24px;
    margin-bottom: 24px;
    box-shadow: var(--elevation-1);
}

.question-number {
    color: var(--text-secondary);
    font-weight: 500;
    font-size: 14px;
    margin-bottom: 16px;
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Noto Sans SC', 'Microsoft YaHei', 'PingFang SC', sans-serif;
}

.question-text {
    font-size: 16px;
    color: var(--text-primary);
    margin-bottom: 20px;
    line-height: 1.5;
    font-weight: 400;
}

.question-content {
    font-size: 16px;
    color: var(--text-primary);
    margin-bottom: 24px;
    line-height: 1.6;
    font-weight: 400;
}

.answer-option {
    margin-bottom: 12px;
}

.answer-option label {
    cursor: pointer;
    padding: 16px 20px;
    border: 1px solid var(--outline-variant);
    border-radius: var(--border-radius-medium);
    display: block;
    transition: all 0.2s cubic-bezier(0.4, 0, 0.2, 1);
    background-color: var(--surface);
    font-size: 14px;
    line-height: 1.4;
    position: relative;
}

.answer-option label:hover {
    background-color: var(--primary-surface);
    border-color: var(--primary-color);
    box-shadow: var(--elevation-1);
}

.answer-option input[type="radio"]:checked + label {
    background-color: var(--primary-color);
    color: white;
    border-color: var(--primary-color);
    box-shadow: var(--elevation-2);
}

.answer-option input[type="radio"] {
    display: none;
}

/* Results page */
.result-card {
    background: var(--surface);
    border: 1px solid var(--divider);
    border-radius: var(--border-radius);
    padding: 2rem;
    text-align: center;
    box-shadow: var(--elevation-2);
}

.score-display {
    font-size: 3rem;
    font-weight: 300;
    color: var(--primary-color);
    margin-bottom: 1rem;
}

.score-label {
    font-size: 1.125rem;
    color: var(--text-secondary);
    margin-bottom: 2rem;
}

/* Navigation buttons */
.nav-buttons {
    position: fixed;
    bottom: 2rem;
    right: 2rem;
    z-index: 1000;
}

.nav-buttons .btn {
    margin-left: 0.5rem;
    box-shadow: var(--elevation-2);
}

@media (max-width: 768px) {
    .nav-buttons {
        position: relative;
        bottom: auto;
        right: auto;
        margin-top: 2rem;
        text-align: center;
    }
}

/* Loading state */
.loading {
    display: flex;
    justify-content: center;
    align-items: center;
    height: 200px;
    color: var(--text-secondary);
}

/* Question navigation buttons */
.question-nav-btn {
    border: 1px solid var(--outline-variant) !important;
    background-color: var(--surface) !important;
    color: var(--text-secondary) !important;
    transition: all 0.2s cubic-bezier(0.4, 0, 0.2, 1) !important;
}

.question-nav-btn:hover {
    background-color: var(--primary-surface) !important;
    border-color: var(--primary-color) !important;
    color: var(--primary-color) !important;
}

.question-nav-btn.btn-primary {
    background-color: var(--primary-color) !important;
    border-color: var(--primary-color) !important;
    color: white !important;
}

.question-nav-btn.btn-warning {
    background-color: #ff9800 !important;
    border-color: #ff9800 !important;
    color: white !important;
}

.question-nav-btn.btn-success {
    background-color: #34a853 !important;
    border-color: #34a853 !important;
    color: white !important;
}

/* Badge styles */
.badge {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Noto Sans SC', 'Microsoft YaHei', 'PingFang SC', sans-serif;
    font-weight: 500;
    letter-spacing: 0.1px;
}

/* Form controls */
.form-control {
    border: 1px solid var(--outline-variant);
    border-radius: var(--border-radius-medium);
    padding: 12px 16px;
    font-size: 14px;
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Noto Sans SC', 'Microsoft YaHei', 'PingFang SC', sans-serif;
    transition: border-color 0.2s cubic-bezier(0.4, 0, 0.2, 1);
}

.form-control:focus {
    border-color: var(--primary-color);
    box-shadow: 0 0 0 4px rgba(115, 49, 249, 0.12);
    outline: none;
}

/* Utility classes */
.text-google-blue {
    color: var(--primary-color) !important;
}

.bg-google-blue {
    background-color: var(--primary-color) !important;
}

.border-google {
    border-color: var(--outline-variant) !important;
}

.shadow-google {
    box-shadow: var(--elevation-1) !important;
}

.shadow-google-hover:hover {
    box-shadow: var(--elevation-2) !important;
}

/* Responsive improvements */
/* 音频播放器样式 */
.audio-player-container {
    background: var(--surface-variant);
    border: 1px solid var(--outline-variant);
    border-radius: var(--border-radius-large);
    padding: 20px;
    margin-bottom: 20px;
}

.audio-player {
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.audio-controls {
    display: flex;
    gap: 12px;
    align-items: center;
    flex-wrap: wrap;
}

.audio-play-btn {
    display: flex;
    align-items: center;
    gap: 8px;
    font-size: 14px;
    font-weight: 500;
    padding: 10px 20px;
    border-radius: 8px;
    transition: all 0.2s ease;
    min-width: 120px;
    justify-content: center;
}

.audio-play-btn:disabled {
    opacity: 0.7;
    cursor: not-allowed;
}

.audio-pause-btn, .audio-replay-btn {
    display: flex;
    align-items: center;
    gap: 6px;
    font-size: 14px;
    font-weight: 500;
    padding: 8px 16px;
    border-radius: 8px;
    transition: all 0.2s ease;
}

.audio-progress {
    width: 100%;
}

.audio-progress .progress {
    height: 6px;
    background-color: var(--outline-variant);
    border-radius: 3px;
    overflow: hidden;
}

.audio-progress .progress-bar {
    background-color: var(--primary-color);
    transition: width 0.1s ease;
    border-radius: 3px;
}

.audio-time {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-top: 8px;
}

.audio-time small {
    font-size: 12px;
    color: var(--text-secondary);
    font-weight: 500;
}

/* 听解题目特殊样式 */
.question-card .audio-player-container {
    border-left: 4px solid #ff9800;
    background: linear-gradient(135deg, #fff8e1 0%, #ffffff 100%);
}

.question-card .audio-player-container::before {
    content: "🎧";
    font-size: 20px;
    position: absolute;
    top: -10px;
    right: 15px;
    background: white;
    padding: 0 8px;
    border-radius: 50%;
    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
}

.question-card .audio-player-container {
    position: relative;
}

/* 音频播放器响应式设计 */
@media (max-width: 768px) {
    .audio-player-container {
        padding: 16px;
        margin-bottom: 16px;
    }
    
    .audio-controls {
        flex-direction: column;
        gap: 8px;
        align-items: stretch;
    }
    
    .audio-play-btn {
        width: 100%;
        min-width: unset;
    }
    
    .audio-pause-btn, .audio-replay-btn {
        width: 100%;
        justify-content: center;
    }
}

@media (max-width: 576px) {
    .audio-player-container {
        padding: 12px;
    }
    
    .audio-controls {
        gap: 6px;
    }
    
    .audio-play-btn, .audio-pause-btn, .audio-replay-btn {
        font-size: 13px;
        padding: 8px 12px;
    }
}

/* 移动端底部操作栏样式 */
.mobile-bottom-bar {
    background: var(--surface);
    border: 1px solid var(--outline-variant);
    border-radius: var(--border-radius-large);
    padding: 16px;
    margin-top: 20px;
    box-shadow: var(--elevation-2);
}

.stat-card {
    background: var(--surface-variant);
    border: 1px solid var(--outline-variant);
    border-radius: var(--border-radius-medium);
    padding: 12px 8px;
    text-align: center;
}

.stat-number {
    font-size: 18px;
    font-weight: 600;
    color: #000000; /* 黑色 */
    line-height: 1;
    margin-bottom: 4px;
}

.stat-label {
    font-size: 11px;
    color: var(--text-secondary);
    font-weight: 500;
}

/* 移动端题目导航网格 */
.question-nav-grid-mobile {
    display: flex;
    flex-wrap: wrap;
    gap: 3px;
    justify-content: flex-start;
}

.mobile-nav-btn {
    flex: 0 0 auto;
}

/* 导航栏移动端优化 */
.navbar-toggler {
    border: none;
    padding: 4px 8px;
}

.navbar-toggler:focus {
    box-shadow: none;
}

.navbar-toggler-icon {
    background-image: url("data:image/svg+xml,%3csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 30 30'%3e%3cpath stroke='rgba%28255, 255, 255, 0.75%29' stroke-linecap='round' stroke-miterlimit='10' stroke-width='2' d='M4 7h22M4 15h22M4 23h22'/%3e%3c/svg%3e");
}

/* 移动端考试头部优化 */
@media (max-width: 768px) {
    .exam-header {
        position: relative !important;
        box-shadow: var(--elevation-1);
        border-bottom: none;
        padding: 8px 0;
    }
    
    .exam-header .container-fluid {
        padding-left: 16px;
        padding-right: 16px;
    }
    
    .exam-header .row {
        align-items: center;
        gap: 8px;
    }
    
    .exam-header .col-md-4 {
        flex: 0 0 auto;
        width: auto;
        margin-bottom: 0;
    }
    
    .exam-header .level-badge {
        width: 32px;
        height: 32px;
        margin-right: 8px;
    }
    
    .exam-header .title-content h5 {
        font-size: 14px;
        margin-bottom: 2px;
    }
    
    .exam-header .title-content small {
        font-size: 10px;
    }
    
    .exam-header .timer-container {
        padding: 6px 12px;
    }
    
    .exam-header .timer-content .time {
        font-size: 16px;
    }
    
    .exam-header .timer-content small {
        font-size: 9px;
    }
    
    .exam-content {
        margin-top: 0 !important;
        padding-top: 16px !important;
        padding-left: 8px !important;
        padding-right: 8px !important;
    }
    
    .container {
        padding-left: 12px;
        padding-right: 12px;
    }
    
    .question-card {
        padding: 16px;
        margin-bottom: 16px;
    }
    
    .exam-card .card-body {
        padding: 16px;
    }
    
    .timer-display {
        padding: 8px 12px;
        min-width: 100px;
    }
    
    .timer-display .time {
        font-size: 16px;
    }
    
    /* 移动端按钮优化 */
    .btn-lg {
        padding: 12px 24px;
        font-size: 16px;
    }
    
    /* 移动端卡片间距优化 */
    .exam-card {
        margin-bottom: 1rem;
    }
    
    /* 移动端文字大小优化 */
    .display-6 {
        font-size: 2rem;
    }
    
    .fs-6 {
        font-size: 0.875rem;
    }
    
    .small {
        font-size: 0.8rem;
    }
}

/* 超小屏幕优化 */
@media (max-width: 576px) {
    .container {
        padding-left: 8px;
        padding-right: 8px;
    }
    
    .exam-content {
        padding-left: 4px !important;
        padding-right: 4px !important;
    }
    
    .question-card {
        padding: 12px;
        margin-bottom: 12px;
    }
    
    .exam-card .card-body {
        padding: 12px;
    }
    
    .mobile-bottom-bar {
        padding: 12px;
        margin-top: 16px;
    }
    
    .stat-card {
        padding: 8px 4px;
    }
    
    .stat-number {
        font-size: 16px;
    }
    
    .stat-label {
        font-size: 10px;
    }
    
    /* 超小屏幕按钮优化 */
    .btn-lg {
        padding: 10px 20px;
        font-size: 15px;
    }
    
    .btn-sm {
        padding: 6px 12px;
        font-size: 13px;
    }
    
    /* 超小屏幕文字优化 */
    .display-6 {
        font-size: 1.75rem;
    }
    
    .h2 {
        font-size: 1.5rem;
    }
    
    .h5 {
        font-size: 1.1rem;
    }
}

/* 移动端导航优化 */
@media (max-width: 991px) {
    .navbar-collapse {
        background: rgba(255, 255, 255, 0.95);
        border-radius: 8px;
        margin-top: 8px;
        padding: 16px;
        box-shadow: var(--elevation-2);
    }
    
    .navbar-nav .nav-link {
        color: var(--text-primary) !important;
        padding: 8px 16px !important;
    }
    
    .navbar-nav .nav-link:hover {
        background-color: var(--primary-surface) !important;
        color: var(--primary-color) !important;
    }
    
    .dropdown-menu {
        position: static !important;
        transform: none !important;
        opacity: 1 !important;
        visibility: visible !important;
        display: block !important;
        box-shadow: none !important;
        border: none !important;
        background: transparent !important;
        padding: 0 !important;
        margin-top: 8px !important;
    }
    
    .dropdown-item {
        padding: 8px 16px !important;
        margin: 2px 0 !important;
        border-radius: 6px !important;
    }
}