/* === features.css - ChatGPT Plus功能介绍页面专用样式 === */

/* 确保导航栏features页面处于激活状态 */
.nav-link[href="features.html"] {
    color: var(--primary-light) !important;
    background: linear-gradient(135deg, rgba(14, 165, 233, 0.15), rgba(99, 102, 241, 0.15));
    box-shadow: 0 4px 15px rgba(14, 165, 233, 0.25);
    border: 1px solid rgba(14, 165, 233, 0.3);
}
/* === 面包屑导航样式（简洁直线版） === */
.breadcrumb-nav {
    margin-bottom: 25px;
    padding-top: 15px;
}
.breadcrumb {
    display: flex;
    align-items: center;
    list-style: none;
    padding: 0;
    margin: 0;
    font-size: 0.9rem;
    font-weight: 400;
}
.breadcrumb-item {
    display: flex;
    align-items: center;
}
.breadcrumb-item a {
    display: flex;
    align-items: center;
    gap: 6px;
    color: var(--text-secondary);
    text-decoration: none;
    padding: 4px 8px;
    border-radius: 6px;
    transition: all 0.3s ease;
    position: relative;
}
.breadcrumb-item a:hover {
    color: var(--primary-light);
    background: rgba(14, 165, 233, 0.08);
    transform: translateY(-1px);
}
.breadcrumb-icon {
    width: 16px;
    height: 16px;
    flex-shrink: 0;
    transition: all 0.3s ease;
}
.breadcrumb-item a:hover .breadcrumb-icon {
    transform: scale(1.1);
    color: var(--primary);
}
.breadcrumb-separator {
    margin: 0 12px;
    color: var(--text-secondary);
    opacity: 0.6;
    display: flex;
    align-items: center;
    font-size: 0.8rem;
}
.breadcrumb-separator svg {
    width: 12px;
    height: 12px;
}
.breadcrumb-item.current {
    color: var(--primary-light);
    font-weight: 600;
}
.breadcrumb-item.current span {
    color: var(--primary-light);
    position: relative;
}
/* 当前页面下划线效果 */
.breadcrumb-item.current span::after {
    content: '';
    position: absolute;
    left: 0;
    bottom: -2px;
    width: 100%;
    height: 2px;
    background: linear-gradient(90deg, var(--primary), var(--secondary));
    border-radius: 1px;
    animation: underlineExpand 0.5s ease-out;
}
@keyframes underlineExpand {
    from {
        width: 0;
        opacity: 0;
    }
    to {
        width: 100%;
        opacity: 1;
    }
}
/* 面包屑入场动画 */
@keyframes breadcrumbSlideIn {
    from {
        opacity: 0;
        transform: translateX(-20px);
    }
    to {
        opacity: 1;
        transform: translateX(0);
    }
}
.breadcrumb-nav {
    animation: breadcrumbSlideIn 0.4s ease-out;
}
.breadcrumb-item {
    animation: breadcrumbSlideIn 0.5s ease-out;
}
.breadcrumb-item:nth-child(1) { animation-delay: 0.1s; }
.breadcrumb-item:nth-child(2) { animation-delay: 0.2s; }
.breadcrumb-item:nth-child(3) { animation-delay: 0.3s; }
/* === 面包屑响应式设计 === */
@media (max-width: 768px) {
    .breadcrumb-nav {
        margin-bottom: 20px;
        padding-top: 12px;
    }
    
    .breadcrumb {
        font-size: 0.85rem;
        flex-wrap: wrap;
        gap: 4px;
    }
    
    .breadcrumb-item a {
        padding: 3px 6px;
        gap: 4px;
    }
    
    .breadcrumb-icon {
        width: 14px;
        height: 14px;
    }
    
    .breadcrumb-separator {
        margin: 0 8px;
    }
    
    .breadcrumb-separator svg {
        width: 10px;
        height: 10px;
    }
}
@media (max-width: 480px) {
    .breadcrumb-nav {
        margin-bottom: 15px;
        padding-top: 10px;
    }
    
    .breadcrumb {
        font-size: 0.8rem;
    }
    
    .breadcrumb-item a {
        padding: 2px 4px;
        gap: 3px;
        border-radius: 4px;
    }
    
    .breadcrumb-icon {
        width: 12px;
        height: 12px;
    }
    
    .breadcrumb-separator {
        margin: 0 6px;
    }
    
    .breadcrumb-separator svg {
        width: 8px;
        height: 8px;
    }
}
/* === 微交互效果 === */
.breadcrumb-item a::before {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: linear-gradient(90deg, transparent, rgba(14, 165, 233, 0.1), transparent);
    transition: left 0.6s ease;
    border-radius: 6px;
}
.breadcrumb-item a:hover::before {
    left: 100%;
}
/* === 高对比度模式适配 === */
@media (prefers-contrast: high) {
    .breadcrumb-item a {
        border: 1px solid transparent;
    }
    
    .breadcrumb-item a:hover {
        border-color: var(--primary);
        background: transparent;
    }
    
    .breadcrumb-item.current span::after {
        height: 3px;
        background: var(--primary);
    }
}
/* === 模型对比表格样式 === */
.model-comparison {
    margin: 80px 0;
}

.comparison-table-wrapper {
    overflow-x: auto;
    margin-top: 40px;
    border-radius: 16px;
    box-shadow: 0 8px 30px rgba(0, 0, 0, 0.15);
}

.comparison-table {
    width: 100%;
    border-collapse: collapse;
    background: var(--bg-card);
    backdrop-filter: blur(10px);
    border-radius: 16px;
    overflow: hidden;
    border: 1px solid var(--border);
}

.comparison-table th,
.comparison-table td {
    padding: 20px 25px;
    text-align: left;
    border-bottom: 1px solid var(--border);
    position: relative;
}

.comparison-table th {
    background: linear-gradient(135deg, rgba(14, 165, 233, 0.1), rgba(99, 102, 241, 0.1));
    font-weight: 600;
    color: var(--text-primary);
    font-size: 1.1rem;
}

.comparison-table td:first-child {
    background: rgba(255, 255, 255, 0.02);
    font-weight: 500;
    color: var(--text-primary);
    border-right: 1px solid var(--border);
}

.column-header {
    text-align: center;
    position: relative;
}

.column-title {
    font-size: 1.2rem;
    font-weight: 700;
    display: block;
    margin-bottom: 4px;
}

.column-subtitle {
    font-size: 0.9rem;
    color: var(--text-secondary);
    font-weight: 400;
}

.free-column {
    background: linear-gradient(135deg, rgba(107, 114, 128, 0.1), rgba(75, 85, 99, 0.1));
}

.plus-column {
    background: linear-gradient(135deg, rgba(14, 165, 233, 0.15), rgba(99, 102, 241, 0.15));
    position: relative;
}

.recommended-badge {
    position: absolute;
    top: -8px;
    right: 10px;
    background: linear-gradient(135deg, var(--primary), var(--secondary));
    color: white;
    padding: 4px 12px;
    border-radius: 12px;
    font-size: 0.8rem;
    font-weight: 600;
    box-shadow: 0 2px 8px rgba(14, 165, 233, 0.3);
}

.highlight-cell {
    color: var(--primary-light);
    font-weight: 600;
    background: linear-gradient(135deg, rgba(14, 165, 233, 0.05), rgba(99, 102, 241, 0.05));
}

.positive-cell {
    color: var(--success);
    font-weight: 600;
}

.negative-cell {
    color: #ef4444;
    font-weight: 500;
    opacity: 0.8;
}

/* === 核心功能网格样式 === */
.core-features {
    margin: 80px 0;
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(350px, 1fr));
    gap: 30px;
    margin-top: 40px;
}

.feature-detailed-card {
    background: var(--bg-card);
    backdrop-filter: blur(10px);
    border: 1px solid var(--border);
    border-radius: 20px;
    padding: 30px;
    transition: all 0.3s ease;
    position: relative;
    overflow: hidden;
    text-align: left;
}

.feature-detailed-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 3px;
    background: linear-gradient(90deg, var(--primary), var(--secondary));
    transform: scaleX(0);
    transition: transform 0.3s ease;
}

.feature-detailed-card:hover::before {
    transform: scaleX(1);
}

.feature-detailed-card:hover {
    transform: translateY(-5px);
    border-color: rgba(14, 165, 233, 0.3);
    box-shadow: 0 15px 40px rgba(14, 165, 233, 0.15);
}

.feature-header {
    display: flex;
    align-items: center;
    justify-content: flex-start;
    gap: 10px;
    margin-bottom: 20px;
}

.feature-header .feature-icon {
    width: 44px;
    height: 44px;
    background: linear-gradient(135deg, var(--primary), var(--secondary));
    border-radius: 12px;
    display: flex;
    align-items: center;
    justify-content: center;
    flex-shrink: 0;
    box-shadow: 0 4px 15px rgba(14, 165, 233, 0.3);
}

.feature-header .feature-icon svg {
    width: 26px;
    height: 26px;
    color: white;
}

.feature-header h3 {
    font-size: 1.3rem;
    font-weight: 600;
    color: var(--text-primary);
    margin: 0;
    flex: 0 0 auto;
    text-align: left;
    width: auto;
}

.feature-detailed-card > p {
    color: var(--text-secondary);
    line-height: 1.7;
    margin-bottom: 20px;
    font-size: 0.95rem;
}

.feature-examples {
    background: rgba(255, 255, 255, 0.03);
    border-radius: 12px;
    padding: 20px;
    border-left: 4px solid var(--primary);
}

.feature-examples h4 {
    font-size: 1rem;
    color: var(--text-primary);
    margin-bottom: 12px;
    font-weight: 600;
}

.feature-examples ul {
    list-style: none;
    padding: 0;
    margin: 0;
}

.feature-examples li {
    color: var(--text-secondary);
    padding: 4px 0;
    font-size: 0.9rem;
    position: relative;
    padding-left: 20px;
}

.feature-examples li::before {
    content: '▸';
    position: absolute;
    left: 0;
    color: var(--primary);
    font-weight: bold;
}

/* === 应用场景样式 === */
.use-cases {
    margin: 80px 0;
}

.use-case-categories {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 30px;
    margin-top: 40px;
}

.use-case-category {
    background: var(--bg-card);
    backdrop-filter: blur(10px);
    border: 1px solid var(--border);
    border-radius: 16px;
    padding: 25px;
    transition: all 0.3s ease;
}

.use-case-category:hover {
    transform: translateY(-3px);
    border-color: rgba(14, 165, 233, 0.3);
    box-shadow: 0 10px 30px rgba(14, 165, 233, 0.1);
}

.category-header {
    display: flex;
    align-items: center;
    gap: 15px;
    margin-bottom: 20px;
    padding-bottom: 15px;
    border-bottom: 1px solid var(--border);
}

.category-icon {
    width: 45px;
    height: 45px;
    background: linear-gradient(135deg, var(--primary), var(--secondary));
    border-radius: 12px;
    display: flex;
    align-items: center;
    justify-content: center;
    flex-shrink: 0;
}

.category-icon svg {
    width: 24px;
    height: 24px;
    color: white;
}

.category-header h3 {
    font-size: 1.2rem;
    font-weight: 600;
    color: var(--text-primary);
    margin: 0;
}

.use-case-list {
    list-style: none;
    padding: 0;
    margin: 0;
}

.use-case-list li {
    color: var(--text-secondary);
    padding: 8px 0;
    font-size: 0.95rem;
    line-height: 1.4;
    display: flex;
    align-items: center;
    gap: 10px;
}

/* === 用户体验对比样式 === */
.experience-comparison {
    margin: 80px 0;
    padding: 50px 40px;
    background: linear-gradient(135deg, rgba(14, 165, 233, 0.05), rgba(99, 102, 241, 0.05));
    border-radius: 20px;
    border: 1px solid rgba(14, 165, 233, 0.1);
}

.experience-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
    gap: 30px;
    margin-top: 40px;
}

.experience-item {
    text-align: center;
    padding: 25px;
    background: rgba(255, 255, 255, 0.05);
    border-radius: 16px;
    border: 1px solid rgba(255, 255, 255, 0.1);
    transition: all 0.3s ease;
}

.experience-item:hover {
    transform: translateY(-5px);
    box-shadow: 0 10px 30px rgba(14, 165, 233, 0.15);
}

.experience-metric {
    margin-bottom: 15px;
}

.metric-value {
    font-size: 3rem;
    font-weight: 800;
    background: linear-gradient(135deg, var(--primary-light), var(--secondary));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    line-height: 1;
    margin-bottom: 8px;
}

.metric-label {
    font-size: 1.1rem;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 10px;
}

.experience-item > p {
    color: var(--text-secondary);
    font-size: 0.9rem;
    line-height: 1.5;
    margin: 0;
}

/* === 升级理由样式 === */
.upgrade-reasons {
    margin: 80px 0;
}

.reasons-container {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
    gap: 30px;
    margin-top: 40px;
}

.reason-card {
    padding: 35px 30px;
    border-radius: 20px;
    border: 1px solid var(--border);
    transition: all 0.3s ease;
    position: relative;
    overflow: hidden;
}

.reason-card.professional {
    background: linear-gradient(135deg, rgba(16, 185, 129, 0.05), rgba(5, 150, 105, 0.05));
    border-color: rgba(16, 185, 129, 0.2);
}

.reason-card.student {
    background: linear-gradient(135deg, rgba(14, 165, 233, 0.05), rgba(59, 130, 246, 0.05));
    border-color: rgba(14, 165, 233, 0.2);
}

.reason-card.business {
    background: linear-gradient(135deg, rgba(139, 92, 246, 0.05), rgba(168, 85, 247, 0.05));
    border-color: rgba(139, 92, 246, 0.2);
}

.reason-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 15px 40px rgba(0, 0, 0, 0.1);
}

.reason-icon {
    width: 60px;
    height: 60px;
    border-radius: 16px;
    display: flex;
    align-items: center;
    justify-content: center;
    margin-bottom: 20px;
}

.professional .reason-icon {
    background: linear-gradient(135deg, #10b981, #059669);
}

.student .reason-icon {
    background: linear-gradient(135deg, var(--primary), var(--primary-dark));
}

.business .reason-icon {
    background: linear-gradient(135deg, #8b5cf6, #a855f7);
}

.reason-icon svg {
    width: 30px;
    height: 30px;
    color: white;
}

.reason-card h3 {
    font-size: 1.4rem;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 15px;
}

.reason-card p {
    color: var(--text-secondary);
    line-height: 1.7;
    font-size: 0.95rem;
}

/* === 响应式适配 === */
@media (max-width: 992px) {
    .features-grid {
        grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
        gap: 25px;
    }
    
    .use-case-categories {
        grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
        gap: 25px;
    }
    
    .experience-grid {
        grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
        gap: 25px;
    }
}

@media (max-width: 768px) {
    .model-comparison,
    .core-features,
    .use-cases,
    .experience-comparison,
    .upgrade-reasons {
        margin: 60px 0;
    }
    
    .comparison-table th,
    .comparison-table td {
        padding: 15px 12px;
        font-size: 0.9rem;
    }
    
    .features-grid {
        grid-template-columns: 1fr;
        gap: 20px;
    }
    
    .feature-detailed-card {
        padding: 25px;
    }
    
    .feature-header {
        gap: 10px;
    }
    
    .feature-header .feature-icon {
        width: 42px;
        height: 42px;
    }
    
    .feature-header h3 {
        font-size: 1.2rem;
    }
    
    .use-case-categories {
        grid-template-columns: 1fr;
        gap: 20px;
    }
    
    .use-case-category {
        padding: 20px;
    }
    
    .experience-comparison {
        padding: 30px 25px;
        margin: 50px 0;
    }
    
    .experience-grid {
        grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
        gap: 20px;
    }
    
    .experience-item {
        padding: 20px;
    }
    
    .metric-value {
        font-size: 2.5rem;
    }
    
    .reasons-container {
        grid-template-columns: 1fr;
        gap: 20px;
    }
    
    .reason-card {
        padding: 25px 20px;
    }
}

@media (max-width: 480px) {
    .comparison-table-wrapper {
        margin-top: 25px;
    }
    
    .comparison-table th,
    .comparison-table td {
        padding: 12px 8px;
        font-size: 0.85rem;
    }
    
    .column-title {
        font-size: 1.1rem;
    }
    
    .column-subtitle {
        font-size: 0.8rem;
    }
    
    .recommended-badge {
        font-size: 0.7rem;
        padding: 2px 8px;
    }
    
    .feature-detailed-card {
        padding: 20px;
    }
    
    .feature-header {
        flex-direction: column;
        text-align: center;
        gap: 10px;
    }
    
    .feature-examples {
        padding: 15px;
    }
    
    .experience-item {
        padding: 15px;
    }
    
    .metric-value {
        font-size: 2rem;
    }
    
    .reason-card {
        padding: 20px 15px;
    }
    
    .reason-card h3 {
        font-size: 1.2rem;
    }
}


/* === Features quick-answer block === */
.feature-quick-answers {
    margin: 42px 0 70px;
}

.feature-answer-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
    gap: 20px;
    margin-top: 32px;
}

.feature-answer-card {
    background: var(--bg-card);
    backdrop-filter: blur(10px);
    border: 1px solid var(--border);
    border-radius: 20px;
    padding: 24px;
    box-shadow: 0 12px 30px rgba(15, 23, 42, 0.14);
}

.feature-answer-card.featured-answer {
    border-color: rgba(14, 165, 233, 0.35);
    background: linear-gradient(135deg, rgba(14, 165, 233, 0.10), rgba(99, 102, 241, 0.12));
}

.feature-answer-label {
    display: inline-block;
    margin-bottom: 12px;
    padding: 6px 12px;
    border-radius: 999px;
    background: rgba(14, 165, 233, 0.14);
    color: var(--primary-light);
    font-size: 0.9rem;
    font-weight: 700;
}

.feature-answer-card p {
    margin: 0;
    color: var(--text-secondary);
    line-height: 1.8;
}

.feature-answer-card a {
    color: var(--primary-light);
    text-decoration: none;
}

.feature-answer-card a:hover {
    text-decoration: underline;
}