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

:root {
    --primary-color: #2563eb;
    --primary-dark: #1d4ed8;
    --secondary-color: #64748b;
    --accent-color: #06b6d4;
    --success-color: #10b981;
    --warning-color: #f59e0b;
    --danger-color: #ef4444;
    --text-primary: #1e293b;
    --text-secondary: #64748b;
    --bg-primary: #ffffff;
    --bg-secondary: #f8fafc;
    --bg-tertiary: #f1f5f9;
    --border-color: #e2e8f0;
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1);
    --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1);
    --gradient-primary: linear-gradient(135deg, #2563eb 0%, #06b6d4 100%);
    --gradient-secondary: linear-gradient(135deg, #6366f1 0%, #8b5cf6 100%);
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'PingFang SC', 'Hiragino Sans GB', 'Microsoft YaHei', sans-serif;
    line-height: 1.6;
    color: var(--text-primary);
    background-color: var(--bg-primary);
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

/* 导航栏 */
.navbar {
    background: linear-gradient(135deg, rgba(255, 255, 255, 0.98) 0%, rgba(248, 250, 252, 0.98) 100%);
    backdrop-filter: blur(20px);
    border-bottom: 1px solid var(--border-color);
    position: sticky;
    top: 0;
    z-index: 1000;
    box-shadow: 0 2px 20px rgba(0, 0, 0, 0.08);
}

.navbar .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 8px 20px;
}

.nav-brand {
    display: flex;
    align-items: center;
    gap: 12px;
    cursor: pointer;
    transition: transform 0.3s;
}

.nav-brand:hover {
    transform: scale(1.02);
}

.logo-icon {
    width: 85px;
    height: 85px;
    background: linear-gradient(135deg, #2563eb 0%, #06b6d4 100%);
    border-radius: 16px;
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    overflow: hidden;
    box-shadow: 0 4px 15px rgba(37, 99, 235, 0.3);
    flex-shrink: 0;
}

.logo-icon svg {
    width: 24px;
    height: 24px;
}

.logo-image {
    width: 100%;
    height: 100%;
    object-fit: contain;
    display: block;
}

.brand-text {
    font-size: 1.25rem;
    font-weight: 800;
    background: linear-gradient(135deg, #2563eb 0%, #06b6d4 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    white-space: nowrap;
    flex-shrink: 0;
}

.nav-menu {
    display: flex;
    list-style: none;
    gap: 2px;
    flex: 1;
    justify-content: center;
}

.nav-menu a {
    text-decoration: none;
    color: var(--text-secondary);
    font-weight: 600;
    transition: all 0.3s;
    position: relative;
    padding: 8px 10px;
    border-radius: 8px;
    font-size: 0.9rem;
    white-space: nowrap;
}

.nav-menu a:hover {
    color: var(--primary-color);
    background: rgba(37, 99, 235, 0.08);
}

.nav-menu a.active {
    color: var(--primary-color);
    background: linear-gradient(135deg, rgba(37, 99, 235, 0.1) 0%, rgba(6, 182, 212, 0.1) 100%);
}

.nav-menu a.active::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 50%;
    transform: translateX(-50%);
    width: 30px;
    height: 3px;
    background: linear-gradient(90deg, #2563eb 0%, #06b6d4 100%);
    border-radius: 2px;
}

.nav-actions {
    display: flex;
    gap: 10px;
    flex-shrink: 0;
}

.btn-login,
.btn-register {
    padding: 10px 24px;
    border-radius: 10px;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s;
    border: none;
    font-size: 0.95rem;
    white-space: nowrap;
    flex-shrink: 0;
}

.btn-login {
    background: transparent;
    color: var(--primary-color);
    border: 2px solid var(--primary-color);
}

.btn-login:hover {
    background: var(--primary-color);
    color: white;
    transform: translateY(-2px);
    box-shadow: 0 4px 15px rgba(37, 99, 235, 0.3);
}

.btn-register {
    background: linear-gradient(135deg, #2563eb 0%, #06b6d4 100%);
    color: white;
    box-shadow: 0 4px 15px rgba(37, 99, 235, 0.3);
}

.btn-register:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(37, 99, 235, 0.4);
}

/* Hero 区域 */
.hero {
    background: linear-gradient(135deg, #f0f9ff 0%, #e0f2fe 50%, #f0fdfa 100%);
    padding: 100px 0;
    position: relative;
    overflow: hidden;
}

.hero::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: url("data:image/svg+xml,%3Csvg width='60' height='60' viewBox='0 0 60 60' xmlns='http://www.w3.org/2000/svg'%3E%3Cg fill='none' fill-rule='evenodd'%3E%3Cg fill='%232563eb' fill-opacity='0.05'%3E%3Cpath d='M36 34v-4h-2v4h-4v2h4v4h2v-4h4v-2h-4zm0-30V0h-2v4h-4v2h4v4h2V6h4V4h-4zM6 34v-4H4v4H0v2h4v4h2v-4h4v-2H6zM6 4V0H4v4H0v2h4v4h2V6h4V4H6z'/%3E%3C/g%3E%3C/g%3E%3C/svg%3E");
    opacity: 0.5;
}

.hero .container {
    display: flex;
    align-items: center;
    gap: 60px;
    position: relative;
    z-index: 1;
}

.hero-content {
    flex: 1;
}

.hero-title {
    font-size: 3rem;
    font-weight: 800;
    line-height: 1.2;
    margin-bottom: 20px;
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.hero-subtitle {
    font-size: 1.25rem;
    color: var(--text-secondary);
    margin-bottom: 30px;
    line-height: 1.8;
}

.hero-buttons {
    display: flex;
    gap: 15px;
}

.btn-primary,
.btn-secondary {
    padding: 14px 32px;
    border-radius: 8px;
    font-weight: 600;
    font-size: 1rem;
    cursor: pointer;
    transition: all 0.3s;
    border: none;
}

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

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-xl);
}

.btn-secondary {
    background: white;
    color: var(--primary-color);
    border: 2px solid var(--primary-color);
}

.btn-secondary:hover {
    background: var(--bg-tertiary);
}

.hero-image {
    flex: 1;
    display: flex;
    justify-content: center;
}

.database-illustration {
    position: relative;
    width: 400px;
    height: 400px;
}

.layer {
    position: absolute;
    border-radius: 20px;
    animation: float 6s ease-in-out infinite;
}

.layer-1 {
    width: 300px;
    height: 300px;
    background: linear-gradient(135deg, rgba(37, 99, 235, 0.2) 0%, rgba(6, 182, 212, 0.2) 100%);
    top: 50px;
    left: 50px;
    animation-delay: 0s;
}

.layer-2 {
    width: 250px;
    height: 250px;
    background: linear-gradient(135deg, rgba(37, 99, 235, 0.3) 0%, rgba(6, 182, 212, 0.3) 100%);
    top: 75px;
    left: 75px;
    animation-delay: 1s;
}

.layer-3 {
    width: 200px;
    height: 200px;
    background: var(--gradient-primary);
    top: 100px;
    left: 100px;
    animation-delay: 2s;
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-size: 4rem;
}

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

/* 统计数据 */
.stats {
    background: white;
    padding: 60px 0;
    border-bottom: 1px solid var(--border-color);
}

.stats-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 30px;
}

.stat-item {
    text-align: center;
    padding: 30px;
    background: var(--bg-secondary);
    border-radius: 12px;
    transition: all 0.3s;
}

.stat-item:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-lg);
}

.stat-number {
    font-size: 2.5rem;
    font-weight: 800;
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    margin-bottom: 10px;
}

.stat-label {
    font-size: 1rem;
    color: var(--text-secondary);
    font-weight: 500;
}

/* 功能特性 */
.features {
    padding: 100px 0;
    background: var(--bg-secondary);
}

.section-title {
    font-size: 2.5rem;
    font-weight: 700;
    text-align: center;
    margin-bottom: 15px;
    color: var(--text-primary);
}

.section-subtitle {
    font-size: 1.125rem;
    color: var(--text-secondary);
    text-align: center;
    margin-bottom: 60px;
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 30px;
}

.feature-card {
    background: white;
    padding: 40px 30px;
    border-radius: 16px;
    box-shadow: var(--shadow-sm);
    transition: all 0.3s;
    text-align: center;
    text-decoration: none;
    color: inherit;
    display: block;
}

.feature-card:hover {
    transform: translateY(-8px);
    box-shadow: var(--shadow-xl);
}

.feature-icon {
    width: 70px;
    height: 70px;
    background: linear-gradient(135deg, rgba(37, 99, 235, 0.1) 0%, rgba(6, 182, 212, 0.1) 100%);
    border-radius: 16px;
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0 auto 25px;
    color: var(--primary-color);
}

.feature-icon svg {
    width: 35px;
    height: 35px;
}

.feature-card h3 {
    font-size: 1.25rem;
    font-weight: 600;
    margin-bottom: 12px;
    color: var(--text-primary);
}

.feature-card p {
    color: var(--text-secondary);
    line-height: 1.6;
}

/* 材料分类 */
.categories {
    padding: 100px 0;
    background: white;
}

.categories-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 30px;
}

.category-card {
    background: var(--bg-secondary);
    padding: 40px 30px;
    border-radius: 16px;
    text-align: center;
    transition: all 0.3s;
    border: 2px solid transparent;
    cursor: pointer;
}

.category-card:hover {
    border-color: var(--primary-color);
    transform: translateY(-5px);
    box-shadow: var(--shadow-lg);
}

.category-icon {
    font-size: 3rem;
    margin-bottom: 20px;
}

.category-card h3 {
    font-size: 1.25rem;
    font-weight: 600;
    margin-bottom: 10px;
    color: var(--text-primary);
}

.category-card p {
    color: var(--text-secondary);
    margin-bottom: 15px;
}

.category-count {
    display: inline-block;
    padding: 6px 16px;
    background: var(--gradient-primary);
    color: white;
    border-radius: 20px;
    font-size: 0.875rem;
    font-weight: 500;
}

/* CTA 区域 */
.cta {
    padding: 80px 0;
    background: var(--gradient-primary);
    text-align: center;
}

.cta-content h2 {
    font-size: 2.5rem;
    font-weight: 700;
    color: white;
    margin-bottom: 15px;
}

.cta-content p {
    font-size: 1.125rem;
    color: rgba(255, 255, 255, 0.9);
    margin-bottom: 30px;
}

.btn-cta {
    padding: 16px 40px;
    background: white;
    color: var(--primary-color);
    border: none;
    border-radius: 8px;
    font-size: 1.125rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s;
    box-shadow: var(--shadow-lg);
}

.btn-cta:hover {
    transform: translateY(-3px);
    box-shadow: var(--shadow-xl);
}

/* 页脚 */
.footer {
    background: var(--text-primary);
    color: white;
    padding: 60px 0 30px;
}

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

.footer-brand {
    display: flex;
    align-items: center;
    gap: 12px;
    margin-bottom: 20px;
}

.footer-brand .logo-icon {
    background: rgba(255, 255, 255, 0.1);
}

.footer-brand span {
    font-size: 1.125rem;
    font-weight: 600;
}

.footer-desc {
    color: rgba(255, 255, 255, 0.7);
    line-height: 1.6;
}

.footer-section h4 {
    font-size: 1.125rem;
    font-weight: 600;
    margin-bottom: 20px;
}

.footer-section ul {
    list-style: none;
}

.footer-section ul li {
    margin-bottom: 12px;
}

.footer-section a {
    color: rgba(255, 255, 255, 0.7);
    text-decoration: none;
    transition: color 0.3s;
}

.footer-section a:hover {
    color: white;
}

.footer-bottom {
    text-align: center;
    padding-top: 30px;
    border-top: 1px solid rgba(255, 255, 255, 0.1);
    color: rgba(255, 255, 255, 0.5);
}

/* 响应式设计 */
@media (max-width: 1200px) {
    .nav-menu a {
        padding: 8px 10px;
        font-size: 0.85rem;
    }
}

@media (max-width: 1024px) {
    .hero .container {
        flex-direction: column;
        text-align: center;
    }

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

    .features-grid,
    .categories-grid {
        grid-template-columns: repeat(2, 1fr);
    }

    .stats-grid {
        grid-template-columns: repeat(2, 1fr);
    }

    .footer-grid {
        grid-template-columns: repeat(2, 1fr);
    }

    .nav-menu {
        gap: 2px;
    }

    .nav-menu a {
        padding: 6px 8px;
        font-size: 0.8rem;
    }
}

@media (max-width: 768px) {
    .nav-menu {
        display: none;
    }

    .hero-title {
        font-size: 2rem;
    }

    .hero-subtitle {
        font-size: 1rem;
    }

    .database-illustration {
        width: 300px;
        height: 300px;
    }

    .features-grid,
    .categories-grid {
        grid-template-columns: 1fr;
    }

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

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

    .section-title {
        font-size: 2rem;
    }
}

/* 模态框样式 */
.modal-overlay {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(0, 0, 0, 0.5);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 2000;
    opacity: 0;
    visibility: hidden;
    transition: all 0.3s ease;
    backdrop-filter: blur(4px);
}

.modal-overlay.active {
    opacity: 1;
    visibility: visible;
}

.modal-container {
    background: white;
    border-radius: 16px;
    width: 100%;
    max-width: 480px;
    max-height: 90vh;
    overflow-y: auto;
    transform: scale(0.9) translateY(20px);
    transition: all 0.3s ease;
    box-shadow: var(--shadow-xl);
}

.modal-overlay.active .modal-container {
    transform: scale(1) translateY(0);
}

.modal-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 24px 32px;
    border-bottom: 1px solid var(--border-color);
}

.modal-header h2 {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--text-primary);
}

.modal-close {
    background: none;
    border: none;
    cursor: pointer;
    padding: 8px;
    border-radius: 8px;
    transition: all 0.3s;
    color: var(--text-secondary);
}

.modal-close:hover {
    background: var(--bg-tertiary);
    color: var(--text-primary);
}

.modal-close svg {
    width: 24px;
    height: 24px;
}

.modal-body {
    padding: 32px;
}

.modal-footer {
    padding: 20px 32px;
    border-top: 1px solid var(--border-color);
    text-align: center;
}

.modal-footer p {
    color: var(--text-secondary);
    font-size: 0.9375rem;
}

.modal-footer a {
    color: var(--primary-color);
    text-decoration: none;
    font-weight: 500;
}

.modal-footer a:hover {
    text-decoration: underline;
}

/* 表单样式 */
.form-group {
    margin-bottom: 20px;
}

.form-group label {
    display: block;
    margin-bottom: 8px;
    font-weight: 500;
    color: var(--text-primary);
    font-size: 0.9375rem;
}

.form-group input {
    width: 100%;
    padding: 12px 16px;
    border: 2px solid var(--border-color);
    border-radius: 8px;
    font-size: 1rem;
    transition: all 0.3s;
    outline: none;
}

.form-group input:focus {
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.1);
}

.form-group input::placeholder {
    color: var(--text-secondary);
}

.password-input {
    position: relative;
}

.password-input input {
    padding-right: 48px;
}

.toggle-password {
    position: absolute;
    right: 12px;
    top: 50%;
    transform: translateY(-50%);
    background: none;
    border: none;
    cursor: pointer;
    padding: 8px;
    color: var(--text-secondary);
    transition: color 0.3s;
}

.toggle-password:hover {
    color: var(--primary-color);
}

.toggle-password svg {
    width: 20px;
    height: 20px;
}

.form-options {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 24px;
}

.checkbox-label {
    display: flex;
    align-items: center;
    gap: 8px;
    cursor: pointer;
    font-size: 0.9375rem;
    color: var(--text-secondary);
}

.checkbox-label input[type="checkbox"] {
    width: 18px;
    height: 18px;
    cursor: pointer;
}

.forgot-password {
    color: var(--primary-color);
    text-decoration: none;
    font-size: 0.9375rem;
    font-weight: 500;
}

.forgot-password:hover {
    text-decoration: underline;
}

.link {
    color: var(--primary-color);
    text-decoration: none;
}

.link:hover {
    text-decoration: underline;
}

.btn-submit {
    width: 100%;
    padding: 14px;
    background: var(--gradient-primary);
    color: white;
    border: none;
    border-radius: 8px;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s;
    box-shadow: var(--shadow-md);
}

.btn-submit:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

.btn-submit:active {
    transform: translateY(0);
}

.form-divider {
    display: flex;
    align-items: center;
    margin: 24px 0;
    color: var(--text-secondary);
    font-size: 0.875rem;
}

.form-divider::before,
.form-divider::after {
    content: '';
    flex: 1;
    height: 1px;
    background: var(--border-color);
}

.form-divider span {
    padding: 0 16px;
}

/* 社交登录 */
.social-login {
    display: flex;
    gap: 12px;
}

.social-btn {
    flex: 1;
    padding: 12px;
    border: 2px solid var(--border-color);
    border-radius: 8px;
    background: white;
    cursor: pointer;
    transition: all 0.3s;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    font-size: 0.9375rem;
    font-weight: 500;
    color: var(--text-primary);
}

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

.social-btn svg {
    width: 20px;
    height: 20px;
}

.social-btn.wechat {
    color: #07c160;
}

.social-btn.wechat svg {
    fill: #07c160;
}

/* 密码强度 */
.password-strength {
    margin-top: 8px;
}

.strength-bar {
    height: 4px;
    background: var(--border-color);
    border-radius: 2px;
    overflow: hidden;
    margin-bottom: 6px;
}

.strength-fill {
    height: 100%;
    width: 0;
    transition: all 0.3s;
    border-radius: 2px;
}

.strength-fill.weak {
    width: 33%;
    background: var(--danger-color);
}

.strength-fill.medium {
    width: 66%;
    background: var(--warning-color);
}

.strength-fill.strong {
    width: 100%;
    background: var(--success-color);
}

.strength-text {
    font-size: 0.8125rem;
    color: var(--text-secondary);
}

/* Toast 提示 */
.toast {
    position: fixed;
    top: 100px;
    right: 20px;
    padding: 16px 24px;
    border-radius: 8px;
    color: white;
    font-weight: 500;
    z-index: 3000;
    transform: translateX(400px);
    transition: transform 0.3s ease;
    box-shadow: var(--shadow-lg);
    max-width: 400px;
}

.toast.show {
    transform: translateX(0);
}

.toast.success {
    background: var(--success-color);
}

.toast.error {
    background: var(--danger-color);
}

.toast.warning {
    background: var(--warning-color);
}

.toast.info {
    background: var(--primary-color);
}

/* 响应式模态框 */
@media (max-width: 768px) {
    .modal-container {
        max-width: 100%;
        margin: 20px;
        border-radius: 12px;
    }

    .modal-header,
    .modal-body,
    .modal-footer {
        padding: 20px;
    }

    .toast {
        left: 20px;
        right: 20px;
        max-width: none;
    }
}