:root {
    --bg-primary: #0f0f1a;
    --bg-secondary: #1a1a2e;
    --bg-card: #16213e;
    --bg-card-hover: #1c2a4a;
    --text-primary: #e2e8f0;
    --text-secondary: #94a3b8;
    --text-muted: #64748b;
    --accent-1: #6366f1;
    --accent-2: #8b5cf6;
    --accent-3: #06b6d4;
    --accent-gradient: linear-gradient(135deg, #6366f1, #8b5cf6, #06b6d4);
    --shadow: 0 8px 32px rgba(0,0,0,0.3);
    --radius: 16px;
    --radius-sm: 10px;
    --transition: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    --border-color: rgba(99, 102, 241, 0.15);
}

[data-theme="light"] {
    --bg-primary: #f8fafc;
    --bg-secondary: #f1f5f9;
    --bg-card: #ffffff;
    --bg-card-hover: #eef2ff;
    --text-primary: #0f172a;
    --text-secondary: #334155;
    --text-muted: #94a3b8;
    --border-color: rgba(99, 102, 241, 0.2);
    --shadow: 0 8px 32px rgba(0,0,0,0.08);
}

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

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
    background: var(--bg-primary);
    color: var(--text-primary);
    line-height: 1.6;
    transition: background var(--transition), color var(--transition);
}

a { text-decoration: none; color: inherit; }
img { max-width: 100%; display: block; }
ul { list-style: none; }

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 24px;
}

/* ========== 导航栏 ========== */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    z-index: 1000;
    background: rgba(15, 15, 26, 0.85);
    backdrop-filter: blur(20px);
    border-bottom: 1px solid transparent;
    transition: all var(--transition);
}

[data-theme="light"] .navbar {
    background: rgba(248, 250, 252, 0.85);
}

.navbar.scrolled {
    background: var(--bg-secondary);
    border-bottom: 1px solid var(--border-color);
    box-shadow: 0 4px 20px rgba(0,0,0,0.1);
}

.navbar .container {
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 68px;
}

.logo {
    display: flex;
    align-items: center;
    gap: 10px;
    font-size: 1.4rem;
    font-weight: 800;
    color: var(--accent-1);
}

.logo i {
    font-size: 1.6rem;
    background: var(--accent-gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.nav-links {
    display: flex;
    gap: 8px;
}

.nav-links a {
    padding: 8px 16px;
    border-radius: 8px;
    font-weight: 500;
    color: var(--text-secondary);
    transition: all var(--transition);
    position: relative;
}

.nav-links a:hover,
.nav-links a.active {
    background: rgba(99, 102, 241, 0.1);
    color: var(--accent-1);
}

.nav-actions {
    display: flex;
    align-items: center;
    gap: 12px;
}

.theme-toggle,
.hamburger {
    background: none;
    border: 2px solid var(--border-color);
    color: var(--text-secondary);
    width: 42px;
    height: 42px;
    border-radius: 12px;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    font-size: 1.1rem;
    transition: all var(--transition);
}

.theme-toggle:hover,
.hamburger:hover {
    border-color: var(--accent-1);
    color: var(--accent-1);
    background: rgba(99, 102, 241, 0.1);
}

.hamburger {
    display: none;
}

/* ========== 英雄区 ========== */
.hero {
    min-height: 100vh;
    display: flex;
    align-items: center;
    position: relative;
    padding: 120px 0 80px;
    background: linear-gradient(135deg, #0f0f1a 0%, #1a1a2e 50%, #16213e 100%);
    overflow: hidden;
}

[data-theme="light"] .hero {
    background: linear-gradient(135deg, #f0f4ff 0%, #e0e7ff 50%, #c7d2fe 100%);
}

.hero .container {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 60px;
    align-items: center;
    position: relative;
    z-index: 2;
}

.hero-content h1 {
    font-size: 3.2rem;
    font-weight: 800;
    line-height: 1.2;
    margin-bottom: 20px;
}

.gradient-text {
    background: var(--accent-gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.hero-content p {
    font-size: 1.1rem;
    color: var(--text-secondary);
    margin-bottom: 32px;
    max-width: 480px;
}

.search-box {
    display: flex;
    align-items: center;
    background: var(--bg-card);
    border-radius: 60px;
    padding: 6px 6px 6px 20px;
    border: 2px solid var(--border-color);
    transition: all var(--transition);
    max-width: 500px;
}

.search-box:focus-within {
    border-color: var(--accent-1);
    box-shadow: 0 0 0 4px rgba(99, 102, 241, 0.15);
}

.search-box i {
    color: var(--text-muted);
    font-size: 1.1rem;
}

.search-box input {
    flex: 1;
    background: none;
    border: none;
    padding: 12px 16px;
    font-size: 1rem;
    color: var(--text-primary);
    outline: none;
    font-family: inherit;
}

.search-box input::placeholder {
    color: var(--text-muted);
}

.hero-tags {
    display: flex;
    align-items: center;
    gap: 10px;
    margin-top: 24px;
    flex-wrap: wrap;
}

.hero-tags span {
    color: var(--text-muted);
    font-size: 0.9rem;
}

.hero-tags a {
    padding: 6px 16px;
    border-radius: 20px;
    background: rgba(99, 102, 241, 0.08);
    border: 1px solid var(--border-color);
    color: var(--text-secondary);
    font-size: 0.85rem;
    font-weight: 500;
    transition: all var(--transition);
}

.hero-tags a:hover {
    background: var(--accent-1);
    color: #fff;
    border-color: var(--accent-1);
}

/* 浮动卡片 */
.hero-visual {
    display: flex;
    justify-content: center;
    align-items: center;
    position: relative;
}

.floating-cards {
    position: relative;
    width: 320px;
    height: 320px;
}

.float-card {
    position: absolute;
    width: 80px;
    height: 80px;
    border-radius: 20px;
    background: var(--bg-card);
    border: 2px solid var(--border-color);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 2rem;
    color: var(--accent-1);
    box-shadow: var(--shadow);
    animation: float 6s ease-in-out infinite;
}

.float-card.c1 { top: 10%; left: 10%; animation-delay: 0s; }
.float-card.c2 { top: 50%; right: 0; animation-delay: 1.5s; }
.float-card.c3 { bottom: 10%; left: 30%; animation-delay: 3s; }
.float-card.c4 { top: 20%; right: 20%; animation-delay: 4.5s; }

@keyframes float {
    0%, 100% { transform: translateY(0) rotate(0deg); }
    50% { transform: translateY(-20px) rotate(5deg); }
}

.hero-wave {
    position: absolute;
    bottom: 0;
    left: 0;
    width: 100%;
    line-height: 0;
}

.hero-wave svg {
    display: block;
}

/* ========== 分类 ========== */
.categories {
    padding: 80px 0;
    background: var(--bg-primary);
}

.section-header {
    text-align: center;
    margin-bottom: 48px;
}

.section-header h2 {
    font-size: 2.2rem;
    font-weight: 700;
    margin-bottom: 8px;
}

.section-header p {
    color: var(--text-secondary);
    font-size: 1.05rem;
}

.category-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(160px, 1fr));
    gap: 16px;
}

.category-item {
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--radius);
    padding: 24px 16px;
    text-align: center;
    cursor: pointer;
    transition: all var(--transition);
}

.category-item:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow);
    border-color: var(--accent-1);
}

.category-item i {
    font-size: 2rem;
    color: var(--accent-1);
    margin-bottom: 12px;
    display: block;
}

.category-item span {
    font-weight: 600;
    font-size: 1rem;
}

.category-item small {
    display: block;
    color: var(--text-muted);
    font-size: 0.8rem;
    margin-top: 4px;
}

.category-item.active {
    background: rgba(99, 102, 241, 0.12);
    border-color: var(--accent-1);
}

/* ========== 工具列表 ========== */
.tools {
    padding: 80px 0;
    background: var(--bg-secondary);
}

.tool-controls {
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 16px;
    margin-bottom: 32px;
}

.sort-btns {
    display: flex;
    gap: 8px;
}

.sort-btn {
    padding: 8px 20px;
    border-radius: 8px;
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    color: var(--text-secondary);
    font-weight: 500;
    cursor: pointer;
    transition: all var(--transition);
    font-family: inherit;
    font-size: 0.9rem;
}

.sort-btn:hover,
.sort-btn.active {
    background: var(--accent-1);
    color: #fff;
    border-color: var(--accent-1);
}

.category-filter select {
    padding: 10px 20px;
    border-radius: 8px;
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    color: var(--text-primary);
    font-family: inherit;
    font-size: 0.9rem;
    cursor: pointer;
    outline: none;
    transition: border var(--transition);
}

.category-filter select:focus {
    border-color: var(--accent-1);
}

.tool-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
    gap: 24px;
}

.tool-card {
    background: var(--bg-card);
    border-radius: var(--radius);
    padding: 24px;
    border: 1px solid var(--border-color);
    transition: all var(--transition);
    display: flex;
    flex-direction: column;
}

.tool-card:hover {
    transform: translateY(-6px);
    box-shadow: var(--shadow);
    border-color: rgba(99, 102, 241, 0.3);
    background: var(--bg-card-hover);
}

.tool-card-header {
    display: flex;
    align-items: flex-start;
    gap: 16px;
    margin-bottom: 16px;
}

.tool-icon {
    width: 52px;
    height: 52px;
    border-radius: 14px;
    background: var(--accent-gradient);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.4rem;
    color: #fff;
    flex-shrink: 0;
}

.tool-icon img {
    width: 100%;
    height: 100%;
    border-radius: 14px;
    object-fit: cover;
}

.tool-info {
    flex: 1;
}

.tool-info h3 {
    font-size: 1.1rem;
    font-weight: 600;
    margin-bottom: 4px;
}

.tool-tag {
    display: inline-block;
    padding: 2px 10px;
    border-radius: 20px;
    background: rgba(99, 102, 241, 0.1);
    color: var(--accent-1);
    font-size: 0.75rem;
    font-weight: 500;
}

.tool-desc {
    color: var(--text-secondary);
    font-size: 0.9rem;
    margin-bottom: 16px;
    flex: 1;
    display: -webkit-box;
    -webkit-line-clamp: 2;
    -webkit-box-orient: vertical;
    overflow: hidden;
}

.tool-card-footer {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding-top: 16px;
    border-top: 1px solid var(--border-color);
}

.tool-hot {
    display: flex;
    align-items: center;
    gap: 6px;
    color: var(--text-muted);
    font-size: 0.85rem;
}

.tool-hot i {
    color: #f43f5e;
}

.tool-link {
    padding: 8px 20px;
    border-radius: 8px;
    background: var(--accent-1);
    color: #fff;
    font-weight: 500;
    font-size: 0.85rem;
    transition: all var(--transition);
    border: none;
    cursor: pointer;
}

.tool-link:hover {
    background: var(--accent-2);
    transform: scale(1.02);
}

/* ========== 统计 ========== */
.stats {
    padding: 80px 0;
    background: var(--bg-primary);
}

.stats .container {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 32px;
    text-align: center;
}

.stat-item {
    padding: 32px 16px;
    border-radius: var(--radius);
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    transition: all var(--transition);
}

.stat-item:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow);
}

.stat-item i {
    font-size: 2.2rem;
    background: var(--accent-gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    margin-bottom: 12px;
}

.stat-number {
    display: block;
    font-size: 2.5rem;
    font-weight: 800;
    background: var(--accent-gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.stat-label {
    color: var(--text-secondary);
    font-size: 1rem;
    margin-top: 4px;
    display: block;
}

/* ========== 提交 ========== */
.submit {
    padding: 80px 0;
    background: var(--bg-secondary);
}

.submit-form {
    max-width: 640px;
    margin: 0 auto;
    display: flex;
    flex-direction: column;
    gap: 16px;
}

.form-row {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 16px;
}

.submit-form input,
.submit-form select,
.submit-form textarea {
    padding: 14px 18px;
    border-radius: var(--radius-sm);
    background: var(--bg-card);
    border: 2px solid var(--border-color);
    color: var(--text-primary);
    font-family: inherit;
    font-size: 0.95rem;
    transition: all var(--transition);
    outline: none;
    width: 100%;
}

.submit-form input:focus,
.submit-form select:focus,
.submit-form textarea:focus {
    border-color: var(--accent-1);
    box-shadow: 0 0 0 4px rgba(99, 102, 241, 0.1);
}

.submit-form textarea {
    resize: vertical;
    min-height: 120px;
}

.btn-primary {
    padding: 14px 32px;
    border-radius: var(--radius-sm);
    background: var(--accent-gradient);
    color: #fff;
    font-weight: 600;
    font-size: 1rem;
    border: none;
    cursor: pointer;
    transition: all var(--transition);
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    font-family: inherit;
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 24px rgba(99, 102, 241, 0.4);
}

/* ========== 页脚 ========== */
.footer {
    background: var(--bg-secondary);
    border-top: 1px solid var(--border-color);
    padding: 48px 0 24px;
}

.footer-content {
    display: grid;
    grid-template-columns: 2fr 1fr 1fr;
    gap: 40px;
    margin-bottom: 32px;
}

.footer-brand {
    display: flex;
    flex-direction: column;
    gap: 8px;
}

.footer-brand i {
    font-size: 2rem;
    background: var(--accent-gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    width: fit-content;
}

.footer-brand span {
    font-size: 1.2rem;
    font-weight: 700;
}

.footer-brand p {
    color: var(--text-muted);
    font-size: 0.9rem;
}

.footer-links h4,
.footer-social h4 {
    font-size: 1rem;
    margin-bottom: 12px;
}

.footer-links a {
    display: block;
    color: var(--text-secondary);
    padding: 4px 0;
    transition: color var(--transition);
}

.footer-links a:hover {
    color: var(--accent-1);
}

.social-icons {
    display: flex;
    gap: 12px;
}

.social-icons a {
    width: 40px;
    height: 40px;
    border-radius: 10px;
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--text-secondary);
    transition: all var(--transition);
}

.social-icons a:hover {
    background: var(--accent-1);
    color: #fff;
    border-color: var(--accent-1);
}

.footer-bottom {
    text-align: center;
    padding-top: 24px;
    border-top: 1px solid var(--border-color);
    color: var(--text-muted);
    font-size: 0.85rem;
}

/* ========== 回到顶部 ========== */
.back-to-top {
    position: fixed;
    bottom: 32px;
    right: 32px;
    width: 48px;
    height: 48px;
    border-radius: 50%;
    background: var(--accent-gradient);
    color: #fff;
    border: none;
    cursor: pointer;
    font-size: 1.2rem;
    box-shadow: 0 4px 16px rgba(99, 102, 241, 0.4);
    opacity: 0;
    visibility: hidden;
    transform: translateY(20px);
    transition: all var(--transition);
    z-index: 999;
}

.back-to-top.show {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
}

.back-to-top:hover {
    transform: translateY(-4px) scale(1.05);
}

/* ========== 空状态 ========== */
.empty-state {
    grid-column: 1 / -1;
    text-align: center;
    padding: 60px 20px;
    color: var(--text-muted);
}

.empty-state i {
    font-size: 3rem;
    margin-bottom: 16px;
    opacity: 0.5;
}

/* ========== 响应式 ========== */
@media (max-width: 1024px) {
    .hero .container {
        grid-template-columns: 1fr;
        text-align: center;
    }

    .hero-content p {
        margin-left: auto;
        margin-right: auto;
    }

    .search-box {
        margin: 0 auto;
    }

    .hero-tags {
        justify-content: center;
    }

    .floating-cards {
        width: 200px;
        height: 200px;
    }

    .float-card {
        width: 60px;
        height: 60px;
        font-size: 1.4rem;
    }
}

@media (max-width: 768px) {
    .navbar .container {
        height: 60px;
    }

    .nav-links {
        position: fixed;
        top: 60px;
        left: 0;
        width: 100%;
        background: var(--bg-secondary);
        flex-direction: column;
        padding: 16px 24px;
        gap: 4px;
        border-bottom: 1px solid var(--border-color);
        transform: translateY(-120%);
        opacity: 0;
        transition: all var(--transition);
        pointer-events: none;
    }

    .nav-links.open {
        transform: translateY(0);
        opacity: 1;
        pointer-events: auto;
    }

    .hamburger {
        display: flex;
    }

    .hero-content h1 {
        font-size: 2.2rem;
    }

    .hero {
        padding: 100px 0 60px;
    }

    .tool-controls {
        flex-direction: column;
        align-items: stretch;
    }

    .sort-btns {
        flex-wrap: wrap;
    }

    .form-row {
        grid-template-columns: 1fr;
    }

    .footer-content {
        grid-template-columns: 1fr;
        text-align: center;
    }

    .footer-brand i {
        margin: 0 auto;
    }

    .social-icons {
        justify-content: center;
    }
}

@media (max-width: 480px) {
    .container {
        padding: 0 16px;
    }

    .hero-content h1 {
        font-size: 1.8rem;
    }

    .section-header h2 {
        font-size: 1.6rem;
    }

    .category-grid {
        grid-template-columns: repeat(auto-fill, minmax(120px, 1fr));
    }

    .tool-grid {
        grid-template-columns: 1fr;
    }

    .stats .container {
        grid-template-columns: 1fr 1fr;
    }
}