/* ========== 全局变量与重置 ========== */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    -webkit-tap-highlight-color: transparent;
}

:root {
    --bg-body: #f9fafb;
    --bg-card: #ffffff;
    --bg-tertiary: #f3f4f6;
    --text-primary: #111827;
    --text-secondary: #4b5563;
    --border: #e5e7eb;
    --accent: #6366f1;
    --accent-light: #818cf8;
    --accent-dark: #4f46e5;
    --header-bg: rgba(255,255,255,0.8);
    --shadow-sm: 0 1px 2px 0 rgba(0,0,0,0.05);
    --shadow-md: 0 4px 6px -1px rgba(0,0,0,0.1), 0 2px 4px -1px rgba(0,0,0,0.06);
    --shadow-lg: 0 10px 15px -3px rgba(0,0,0,0.1), 0 4px 6px -2px rgba(0,0,0,0.05);
    --shadow-xl: 0 20px 25px -5px rgba(0,0,0,0.1), 0 10px 10px -5px rgba(0,0,0,0.04);
    --transition-fast: 0.15s cubic-bezier(0.4, 0, 0.2, 1);
    --transition-normal: 0.2s cubic-bezier(0.4, 0, 0.2, 1);
    --transition-slow: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

body.dark {
    --bg-body: #0f172a;
    --bg-card: #1e293b;
    --bg-tertiary: #334155;
    --text-primary: #f1f5f9;
    --text-secondary: #94a3b8;
    --border: #334155;
    --accent: #818cf8;
    --accent-light: #a5b4fc;
    --accent-dark: #6366f1;
    --header-bg: rgba(15,23,42,0.8);
}

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Helvetica, sans-serif;
    background: var(--bg-body);
    color: var(--text-primary);
    scroll-behavior: smooth;
    line-height: 1.5;
}

.container {
    max-width: 1280px;
    margin: 0 auto;
    padding: 0 1.5rem;
}

/* ========== 滚动按钮 ========== */
.scroll-buttons {
    position: fixed;
    bottom: 1.5rem;
    right: 1.5rem;
    display: flex;
    flex-direction: column;
    gap: 0.75rem;
    z-index: 99;
}

.scroll-btn {
    background: var(--accent);
    border: none;
    color: white;
    width: 44px;
    height: 44px;
    border-radius: 50%;
    cursor: pointer;
    font-size: 1.5rem;
    font-weight: bold;
    box-shadow: var(--shadow-lg);
    transition: all var(--transition-fast);
    display: flex;
    align-items: center;
    justify-content: center;
}

.scroll-btn:hover {
    transform: translateY(-4px) scale(1.05);
    background: var(--accent-dark);
    box-shadow: var(--shadow-xl);
}

/* ========== 头部导航 ========== */
.header {
    position: sticky;
    top: 0;
    z-index: 100;
    background: var(--header-bg);
    backdrop-filter: blur(12px);
    border-bottom: 1px solid var(--border);
}

.navbar {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 0.75rem 1.5rem;
    max-width: 1400px;
    margin: 0 auto;
}

.logo {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    text-decoration: none;
}

.brand-text {
    font-size: 1.5rem;
    font-weight: 700;
    letter-spacing: -0.02em;
}

.brand-text-red {
    color: #ff6b6b;
}

.brand-text-blue {
    color: var(--accent);
}

.nav-menu {
    display: flex;
    gap: 0.5rem;
    list-style: none;
}

.nav-link {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.5rem 1rem;
    border-radius: 2rem;
    text-decoration: none;
    color: var(--text-secondary);
    font-weight: 500;
    font-size: 0.9rem;
    transition: all var(--transition-fast);
}

.nav-link svg {
    width: 18px;
    height: 18px;
}

.nav-link.active,
.nav-link:hover {
    color: var(--accent);
    background: var(--bg-tertiary);
    transform: translateY(-1px);
}

.nav-actions {
    display: flex;
    gap: 0.5rem;
}

.action-btn {
    background: transparent;
    border: none;
    cursor: pointer;
    font-size: 1.2rem;
    color: var(--text-secondary);
    width: 36px;
    height: 36px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all var(--transition-fast);
}

.action-btn:hover {
    transform: scale(1.1);
    color: var(--accent);
    background: var(--bg-tertiary);
}

.mobile-menu-toggle {
    display: none;
    flex-direction: column;
    gap: 4px;
    cursor: pointer;
}

.mobile-menu-toggle span {
    width: 24px;
    height: 2px;
    background: var(--text-primary);
    border-radius: 2px;
    transition: all var(--transition-fast);
}

/* ========== 卡片 ========== */
.card {
    background: var(--bg-card);
    border-radius: 1.5rem;
    border: 1px solid var(--border);
    padding: 1.5rem;
    box-shadow: var(--shadow-sm);
    transition: all var(--transition-normal);
}

.card:hover {
    transform: translateY(-6px);
    box-shadow: var(--shadow-xl);
    border-color: var(--accent-light);
}

/* ========== 按钮 ========== */
.primary-btn, .secondary-btn, .icon-btn {
    padding: 0.5rem 1.25rem;
    border-radius: 2rem;
    border: none;
    font-weight: 500;
    cursor: pointer;
    transition: all var(--transition-fast);
    font-size: 0.9rem;
}

.primary-btn {
    background: var(--accent);
    color: white;
    box-shadow: var(--shadow-sm);
}

.primary-btn:hover {
    background: var(--accent-dark);
    transform: scale(1.02);
    box-shadow: var(--shadow-md);
}

.secondary-btn {
    background: var(--bg-tertiary);
    color: var(--text-primary);
    border: 1px solid var(--border);
}

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

.icon-btn {
    background: transparent;
    padding: 0.5rem;
    border-radius: 50%;
}

.icon-btn:hover {
    background: var(--bg-tertiary);
    transform: scale(1.05);
}

/* ========== 区块 ========== */
.section {
    padding: 4rem 0;
}

.section-header {
    text-align: center;
    margin-bottom: 3rem;
}

.section-title {
    font-size: 2.25rem;
    font-weight: 700;
    margin-bottom: 0.75rem;
    letter-spacing: -0.02em;
}

.section-description {
    color: var(--text-secondary);
    font-size: 1.1rem;
}

/* ========== 配色生成器 ========== */
.generator-workspace {
    display: grid;
    grid-template-columns: 1fr 1.5fr;
    gap: 1.5rem;
}

@media (max-width: 768px) {
    .generator-workspace {
        grid-template-columns: 1fr;
    }
}

.control-group {
    margin-bottom: 1.25rem;
}

.control-group label {
    display: block;
    margin-bottom: 0.5rem;
    font-weight: 500;
    font-size: 0.9rem;
}

.color-input-group {
    display: flex;
    gap: 0.75rem;
    align-items: center;
}

input[type="color"] {
    width: 48px;
    height: 40px;
    border: 1px solid var(--border);
    border-radius: 0.75rem;
    cursor: pointer;
    background: var(--bg-card);
}

input, select, textarea {
    background: var(--bg-card);
    border: 1px solid var(--border);
    padding: 0.5rem 0.75rem;
    border-radius: 0.75rem;
    color: var(--text-primary);
    font-size: 0.9rem;
    transition: all var(--transition-fast);
}

input:focus, select:focus, textarea:focus {
    outline: none;
    border-color: var(--accent);
    box-shadow: 0 0 0 3px rgba(99,102,241,0.2);
}

.slider-group {
    display: flex;
    gap: 0.75rem;
    align-items: center;
}

/* 调色板 */
.color-palette {
    display: flex;
    flex-wrap: wrap;
    border-radius: 1rem;
    overflow: hidden;
    margin: 1rem 0;
}

.palette-item {
    flex: 1;
    min-width: 80px;
    height: 120px;
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    text-shadow: 0 1px 2px rgba(0,0,0,0.2);
    cursor: pointer;
    transition: all var(--transition-fast);
    font-weight: 500;
}

.palette-item:hover {
    transform: scale(1.02);
    filter: brightness(0.95);
    z-index: 2;
    box-shadow: 0 8px 20px rgba(0,0,0,0.2);
}

.palette-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1rem;
}

.color-formats {
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
    margin-top: 1rem;
}

/* ========== 工具网格 ========== */
.tools-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(340px, 1fr));
    gap: 1.5rem;
}

.tool-card {
    display: flex;
    flex-direction: column;
    gap: 0.75rem;
}

.tool-header {
    display: flex;
    align-items: center;
    gap: 0.75rem;
}

.tool-icon {
    font-size: 2rem;
    transition: transform var(--transition-fast);
}

.tool-card:hover .tool-icon {
    transform: scale(1.1);
}

/* 取色器 */
.upload-label {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 0.5rem;
    cursor: pointer;
    border: 2px dashed var(--border);
    border-radius: 1rem;
    padding: 1.5rem;
    transition: all var(--transition-fast);
}

.upload-label:hover {
    border-color: var(--accent);
    background: rgba(99,102,241,0.05);
    transform: translateY(-2px);
}

.extracted-colors {
    display: flex;
    gap: 0.75rem;
    flex-wrap: wrap;
    margin: 0.75rem 0;
}

/* 渐变生成器 */
.gradient-preview {
    height: 120px;
    border-radius: 1rem;
    margin-bottom: 1rem;
    transition: transform var(--transition-fast);
    cursor: pointer;
}

.gradient-preview:hover {
    transform: scale(1.01);
}

.color-stop {
    display: flex;
    gap: 0.75rem;
    align-items: center;
    margin-bottom: 0.75rem;
    flex-wrap: wrap;
}

.color-stop button {
    background: none;
    border: none;
    cursor: pointer;
    font-size: 1rem;
    color: var(--text-secondary);
    transition: all var(--transition-fast);
}

.color-stop button:hover {
    transform: scale(1.2);
    color: #ef4444;
}

/* 对比度检查器 */
.contrast-inputs {
    display: flex;
    gap: 1rem;
    margin-bottom: 1rem;
}

.contrast-result {
    display: flex;
    gap: 1rem;
    align-items: baseline;
    margin-bottom: 1rem;
    font-size: 1rem;
}

.contrast-preview {
    padding: 1rem;
    text-align: center;
    border-radius: 1rem;
    font-weight: 500;
    transition: all var(--transition-fast);
    cursor: pointer;
}

.contrast-preview:hover {
    transform: scale(1.02);
}

/* 色彩库 */
.library-filters {
    display: flex;
    flex-wrap: wrap;
    gap: 0.75rem;
    justify-content: center;
    margin-bottom: 2rem;
}

.filter-btn {
    padding: 0.5rem 1.25rem;
    border-radius: 2rem;
    background: var(--bg-card);
    border: 1px solid var(--border);
    cursor: pointer;
    font-weight: 500;
    transition: all var(--transition-fast);
}

.filter-btn:hover {
    transform: translateY(-2px);
    background: var(--accent);
    color: white;
    border-color: var(--accent);
}

.filter-btn.active {
    background: var(--accent);
    color: white;
    border-color: var(--accent);
    box-shadow: var(--shadow-sm);
}

.palette-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
    gap: 1.5rem;
    margin-top: 2rem;
}

.palette-color-block {
    transition: all var(--transition-fast);
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 0.75rem;
    font-weight: 600;
    text-shadow: 0 1px 2px rgba(0,0,0,0.3);
}

.palette-color-block:hover {
    transform: scale(1.02) translateY(-4px);
    box-shadow: 0 12px 20px -8px rgba(0,0,0,0.25);
    filter: brightness(0.96);
    z-index: 2;
}

/* 统一按钮样式 */
.copy-all-colors {
    background: var(--bg-tertiary);
    color: var(--text-primary);
    border: 1px solid var(--border);
    transition: all var(--transition-fast);
}

.copy-all-colors:hover {
    background: var(--accent);
    color: white;
    border-color: var(--accent);
    transform: translateY(-2px);
}

/* 配色趋势 */
.trends-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
    gap: 1.5rem;
}

.trend-card {
    text-align: center;
}

.trend-preview {
    height: 140px;
    border-radius: 1rem;
    margin-bottom: 1rem;
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-weight: 700;
    transition: all var(--transition-fast);
    background-size: cover;
}

.trend-card:hover .trend-preview {
    transform: scale(1.02);
    box-shadow: var(--shadow-lg);
}

.trend-colors {
    display: flex;
    justify-content: center;
    gap: 0.5rem;
    margin: 0.75rem 0;
}

.trend-color {
    width: 40px;
    height: 40px;
    border-radius: 0.75rem;
    border: 1px solid var(--border);
    transition: all var(--transition-fast);
}

.trend-color:hover {
    transform: scale(1.15);
    box-shadow: var(--shadow-md);
}

/* 关于页面 */
.about-content {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 1.5rem;
}

.use-cases {
    display: grid;
    gap: 1rem;
}

/* 历史记录 */
.history-list {
    max-height: 280px;
    overflow-y: auto;
}

.history-item {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    padding: 0.75rem;
    border-bottom: 1px solid var(--border);
    cursor: pointer;
    transition: all var(--transition-fast);
    border-radius: 0.75rem;
}

.history-item:hover {
    background: var(--bg-tertiary);
    transform: translateX(4px);
}

.delete-history {
    margin-left: auto;
    background: none;
    border: none;
    cursor: pointer;
    font-size: 1rem;
    transition: all var(--transition-fast);
    opacity: 0.6;
}

.delete-history:hover {
    transform: scale(1.2);
    opacity: 1;
    color: #ef4444;
}

/* 页脚 */
.footer {
    background: var(--bg-card);
    border-top: 1px solid var(--border);
    padding: 3rem 0;
    margin-top: 3rem;
}

.footer-content {
    display: flex;
    flex-wrap: wrap;
    justify-content: space-between;
    gap: 2rem;
}

.footer-links {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.footer-links a {
    color: var(--text-secondary);
    text-decoration: none;
    transition: all var(--transition-fast);
    display: inline-block;
}

.footer-links a:hover {
    color: var(--accent);
    transform: translateX(4px);
}

.footer-bottom {
    margin-top: 2rem;
    text-align: center;
    border-top: 1px solid var(--border);
    padding-top: 1.5rem;
    color: var(--text-secondary);
    font-size: 0.875rem;
}

/* 模态框 */
.modal {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0,0,0,0.6);
    backdrop-filter: blur(4px);
    justify-content: center;
    align-items: center;
    z-index: 1000;
}

.modal-content {
    background: var(--bg-card);
    border-radius: 1.5rem;
    width: 90%;
    max-width: 500px;
    padding: 1.5rem;
    animation: fadeInUp 0.2s ease-out;
}

@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.modal-actions {
    display: flex;
    gap: 0.75rem;
    justify-content: flex-end;
    margin-top: 1rem;
}

/* 响应式 */
@media (max-width: 768px) {
    .nav-menu, .nav-actions {
        display: none;
    }
    .mobile-menu-toggle {
        display: flex;
    }
    .container {
        padding: 0 1rem;
    }
    .section-title {
        font-size: 1.75rem;
    }
    .palette-item {
        min-width: 60px;
        height: 90px;
        font-size: 0.7rem;
    }
}

/* 首页 Hero */
.hero-section {
    text-align: center;
    padding: 5rem 0;
}

.hero-title {
    font-size: 3rem;
    font-weight: 800;
    letter-spacing: -0.02em;
    margin-bottom: 1rem;
    background: linear-gradient(135deg, var(--accent), var(--accent-light));
    -webkit-background-clip: text;
    background-clip: text;
    color: transparent;
}

.hero-subtitle {
    font-size: 1.25rem;
    color: var(--text-secondary);
    margin-bottom: 2rem;
}

.feature-tag {
    display: inline-block;
    background: var(--accent);
    color: white;
    padding: 0.25rem 1rem;
    border-radius: 2rem;
    margin: 0 0.5rem;
    font-size: 0.8rem;
    font-weight: 500;
    transition: all var(--transition-fast);
}

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

.cta-btn {
    margin-top: 1.5rem;
    background: var(--accent);
    color: white;
    border: none;
    padding: 0.75rem 2rem;
    border-radius: 2rem;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all var(--transition-fast);
    box-shadow: var(--shadow-md);
}

.cta-btn:hover {
    transform: scale(1.05);
    background: var(--accent-dark);
    box-shadow: var(--shadow-lg);
}

/* 全局提示 */
.global-toast {
    position: fixed;
    top: 5rem;
    right: 1.5rem;
    background: var(--accent);
    color: white;
    padding: 0.75rem 1.5rem;
    border-radius: 2rem;
    font-size: 0.875rem;
    font-weight: 500;
    box-shadow: var(--shadow-lg);
    z-index: 1000;
    opacity: 0;
    transform: translateX(30px);
    transition: all 0.2s ease;
    pointer-events: none;
}

.global-toast.show {
    opacity: 1;
    transform: translateX(0);
}