/* ============================================
   Rewind Lab - Global Styles V1.0
   品牌色: 🟠 暖琥珀 #E67E22
   ============================================ */

/* ===== CSS 变量 ===== */
:root {
    --color-primary: #E67E22;
    --color-primary-dark: #D35400;
    --color-primary-light: #F4A261;
    --color-background: #FFFFFF;
    --color-surface: #FAFAFA;
    --color-text: #2D3748;
    --color-text-light: #718096;
    --color-border: #E2E8F0;
    --color-success: #48BB78;
    --color-error: #E53E3E;
    --space-xs: 4px;
    --space-sm: 8px;
    --space-md: 16px;
    --space-lg: 24px;
    --space-xl: 32px;
    --space-2xl: 48px;
    --radius-sm: 4px;
    --radius-md: 8px;
    --radius-lg: 12px;
    --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.1);
    --shadow-md: 0 4px 6px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 10px 15px rgba(0, 0, 0, 0.15);
    --transition-fast: 150ms ease;
    --transition-normal: 250ms ease;
}

/* ===== 重置 ===== */
*, *::before, *::after {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'PingFang SC', 'Hiragino Sans GB', 'Microsoft YaHei', sans-serif;
    font-size: 16px;
    line-height: 1.6;
    color: var(--color-text);
    background-color: var(--color-background);
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

/* ===== 通用容器 ===== */
.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--space-lg);
}

/* ===== 导航栏 ===== */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    background: var(--color-background);
    border-bottom: 1px solid var(--color-border);
    z-index: 1000;
    box-shadow: var(--shadow-sm);
}

.nav-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--space-lg);
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 64px;
}

.nav-brand {
    display: flex;
    align-items: center;
    gap: var(--space-sm);
}

.nav-logo {
    width: 36px;
    height: 36px;
    object-fit: contain;
}

.nav-title {
    font-size: 18px;
    font-weight: 700;
    color: var(--color-text);
    letter-spacing: -0.02em;
}

.nav-menu {
    display: flex;
    align-items: center;
    gap: var(--space-lg);
    list-style: none;
}

.nav-link {
    color: var(--color-text-light);
    text-decoration: none;
    font-size: 15px;
    font-weight: 500;
    transition: color var(--transition-fast);
    padding: 8px 0;
}

.nav-link:hover,
.nav-link.active {
    color: var(--color-primary);
}

.nav-btn {
    padding: 8px 16px;
    font-size: 14px;
    border-radius: var(--radius-md);
    text-decoration: none;
    font-weight: 600;
    transition: all var(--transition-fast);
    border: 2px solid transparent;
}

.nav-btn-primary {
    background: var(--color-primary);
    color: #fff;
    border-color: var(--color-primary);
}

.nav-btn-primary:hover {
    background: var(--color-primary-dark);
    border-color: var(--color-primary-dark);
}

.nav-toggle {
    display: none;
    flex-direction: column;
    gap: 5px;
    padding: var(--space-sm);
    background: none;
    border: none;
    cursor: pointer;
}

.hamburger-line {
    display: block;
    width: 22px;
    height: 2px;
    background: var(--color-text);
    transition: all var(--transition-normal);
    border-radius: 1px;
}

/* ===== Hero 首屏 ===== */
.hero {
    padding: var(--space-2xl) 0;
    min-height: 60vh;
    display: flex;
    align-items: center;
    justify-content: center;
    background: linear-gradient(180deg, var(--color-background) 0%, var(--color-surface) 100%);
    margin-top: 64px;
}

.hero-container {
    max-width: 800px;
    margin: 0 auto;
    padding: var(--space-xl);
    text-align: center;
}

.hero-title {
    font-size: 48px;
    font-weight: 700;
    color: var(--color-text);
    margin-bottom: var(--space-md);
    letter-spacing: -0.02em;
}

.hero-subtitle {
    font-size: 28px;
    font-weight: 600;
    color: var(--color-primary);
    margin-bottom: var(--space-sm);
}

.hero-description {
    font-size: 18px;
    color: var(--color-text-light);
    margin-bottom: var(--space-xl);
}

.hero-cta {
    display: flex;
    gap: var(--space-md);
    justify-content: center;
    margin-bottom: var(--space-xl);
    flex-wrap: wrap;
}

.hero-badges {
    display: flex;
    gap: var(--space-sm);
    justify-content: center;
    flex-wrap: wrap;
}

.badge {
    display: inline-flex;
    align-items: center;
    gap: var(--space-xs);
    padding: 6px 12px;
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-sm);
    font-size: 14px;
    color: var(--color-text-light);
}

/* ===== 按钮 ===== */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 12px 24px;
    font-size: 16px;
    font-weight: 500;
    border-radius: var(--radius-md);
    cursor: pointer;
    text-decoration: none;
    transition: all var(--transition-normal);
    border: 2px solid transparent;
}

.btn-primary {
    background: var(--color-primary);
    color: #fff;
    border-color: var(--color-primary);
}

.btn-primary:hover {
    background: var(--color-primary-dark);
    border-color: var(--color-primary-dark);
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
}

.btn-secondary {
    background: transparent;
    color: var(--color-text);
    border-color: var(--color-border);
}

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

/* ===== 章节标题 ===== */
.section-title {
    font-size: 32px;
    font-weight: 700;
    text-align: center;
    margin-bottom: var(--space-sm);
}

.section-subtitle {
    font-size: 16px;
    color: var(--color-text-light);
    text-align: center;
    margin-bottom: var(--space-2xl);
}

/* ===== 案例卡片 ===== */
.cases {
    padding: var(--space-2xl) 0;
    background: var(--color-surface);
}

.cases-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: var(--space-lg);
}

.case-card {
    background: var(--color-background);
    border-radius: var(--radius-lg);
    overflow: hidden;
    box-shadow: var(--shadow-sm);
    transition: all var(--transition-normal);
    cursor: pointer;
}

.case-card:hover {
    box-shadow: var(--shadow-lg);
    transform: translateY(-4px);
}

.case-thumbnail {
    height: 160px;
    display: flex;
    align-items: center;
    justify-content: center;
    color: #fff;
    position: relative;
}

.case-label {
    position: absolute;
    top: 12px;
    left: 12px;
    font-size: 12px;
    font-weight: 600;
    background: rgba(0, 0, 0, 0.5);
    padding: 4px 8px;
    border-radius: var(--radius-sm);
    letter-spacing: 0.1em;
}

.case-icon {
    opacity: 0.8;
}

.case-info {
    padding: var(--space-lg);
}

.case-info h3 {
    font-size: 18px;
    font-weight: 600;
    margin-bottom: var(--space-xs);
}

.case-era {
    font-size: 13px;
    color: var(--color-primary);
    font-weight: 500;
    margin-bottom: var(--space-xs);
}

.case-features {
    font-size: 14px;
    color: var(--color-text-light);
}

/* ===== 承诺卡片 ===== */
.promises {
    padding: var(--space-2xl) 0;
}

.promises-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
    gap: var(--space-lg);
}

.promise-card {
    text-align: center;
    padding: var(--space-xl);
    background: var(--color-surface);
    border-radius: var(--radius-lg);
    transition: all var(--transition-normal);
}

.promise-card:hover {
    box-shadow: var(--shadow-md);
    transform: translateY(-2px);
}

.promise-icon {
    color: var(--color-primary);
    margin-bottom: var(--space-md);
    font-size: 32px;
}

.promise-card h3 {
    font-size: 16px;
    font-weight: 600;
    margin-bottom: var(--space-sm);
}

.promise-card p {
    font-size: 14px;
    color: var(--color-text-light);
}

/* ===== 页脚 ===== */
.footer {
    background: var(--color-text);
    color: #fff;
    padding: var(--space-2xl) 0 var(--space-lg);
    margin-top: auto;
}

.footer-content {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: var(--space-lg);
    text-align: center;
}

.footer-brand {
    display: flex;
    align-items: center;
    gap: var(--space-sm);
    font-size: 18px;
    font-weight: 600;
}

.footer-logo {
    width: 32px;
    height: 32px;
    filter: brightness(0) invert(1);
}

.footer-tagline {
    margin-left: var(--space-sm);
    font-size: 13px;
    font-weight: 400;
    color: var(--color-primary-light);
    letter-spacing: 0.05em;
}

.footer-links {
    display: flex;
    gap: var(--space-lg);
    flex-wrap: wrap;
    justify-content: center;
}

.footer-links a {
    color: #A0AEC0;
    text-decoration: none;
    font-size: 14px;
    transition: color var(--transition-fast);
}

.footer-links a:hover {
    color: var(--color-primary-light);
}

.footer-meta {
    display: flex;
    gap: var(--space-lg);
    font-size: 13px;
    color: #718096;
    margin-top: var(--space-md);
    padding-top: var(--space-md);
    border-top: 1px solid #4A5568;
    width: 100%;
    justify-content: center;
}

/* ===== 通用页面样式 ===== */
.page-main {
    padding-top: 96px;
    padding-bottom: 48px;
    min-height: calc(100vh - 64px);
    background: var(--color-surface);
}

.page-hero {
    text-align: center;
    padding: 48px 0 32px;
}

.page-hero h1 {
    font-size: 36px;
    font-weight: 700;
    color: var(--color-text);
    margin-bottom: 8px;
}

.page-hero p {
    font-size: 16px;
    color: var(--color-text-light);
}

.page-content {
    max-width: 900px;
    margin: 0 auto;
    display: grid;
    gap: 24px;
}

.info-card {
    background: var(--color-background);
    padding: 24px;
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-sm);
    border-left: 4px solid var(--color-primary);
}

.info-card h2 {
    font-size: 18px;
    font-weight: 700;
    color: var(--color-text);
    margin-bottom: 12px;
}

.info-card p,
.info-card li {
    color: var(--color-text-light);
    line-height: 1.7;
    margin-bottom: 8px;
}

/* ===== 更新日志专用 ===== */
.changelog-grid {
    display: grid;
    gap: 24px;
}

.changelog-item {
    background: var(--color-background);
    padding: 24px;
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-sm);
    border-left: 4px solid var(--color-primary);
}

.changelog-version {
    display: flex;
    align-items: center;
    gap: 12px;
    margin-bottom: 12px;
}

.version-badge {
    padding: 4px 12px;
    background: var(--color-primary);
    color: #fff;
    border-radius: 12px;
    font-size: 13px;
    font-weight: 600;
}

.version-date {
    font-size: 13px;
    color: var(--color-text-light);
}

.changelog-title {
    font-size: 16px;
    font-weight: 600;
    color: var(--color-text);
    margin-bottom: 8px;
}

.changelog-list {
    list-style: none;
    padding: 0;
}

.changelog-list li {
    padding: 4px 0;
    padding-left: 20px;
    position: relative;
    color: var(--color-text-light);
    font-size: 14px;
}

.changelog-list li::before {
    content: "•";
    position: absolute;
    left: 0;
    color: var(--color-primary);
}

/* ===== 响应式适配 ===== */
@media (max-width: 768px) {
    .nav-container {
        padding: 0 var(--space-md);
    }

    .nav-toggle {
        display: flex;
    }

    .nav-menu {
        position: fixed;
        top: 64px;
        left: 0;
        right: 0;
        background: var(--color-background);
        flex-direction: column;
        padding: var(--space-lg);
        border-bottom: 1px solid var(--color-border);
        box-shadow: var(--shadow-lg);
        transform: translateY(-100%);
        opacity: 0;
        visibility: hidden;
        transition: all var(--transition-normal);
    }

    .nav-menu.active {
        transform: translateY(0);
        opacity: 1;
        visibility: visible;
    }

    .nav-menu li {
        width: 100%;
    }

    .nav-link {
        display: block;
        padding: var(--space-md) 0;
        font-size: 16px;
        border-bottom: 1px solid var(--color-border);
    }

    .nav-link:last-child {
        border-bottom: none;
    }

    .nav-btn {
        width: 100%;
        text-align: center;
        margin-top: var(--space-sm);
    }

    .hero {
        padding: var(--space-lg) 0;
        min-height: auto;
    }

    .hero-title {
        font-size: 36px;
    }

    .hero-subtitle {
        font-size: 22px;
    }

    .hero-cta {
        flex-direction: column;
        align-items: center;
    }

    .hero-cta .btn {
        width: 100%;
        max-width: 280px;
    }

    .section-title {
        font-size: 26px;
    }

    .cases-grid,
    .promises-grid {
        grid-template-columns: 1fr;
    }

    .info-card {
        padding: 20px;
    }

    .changelog-version {
        flex-direction: column;
        align-items: flex-start;
    }
}

@media (max-width: 480px) {
    .container {
        padding: 0 var(--space-md);
    }

    .hero-title {
        font-size: 30px;
    }

    .badge {
        font-size: 12px;
        padding: 4px 8px;
    }

    .page-hero h1 {
        font-size: 28px;
    }
}