/* 绿色环保主题 CSS */
:root {
    /* 绿色调色板 */
    --primary-dark: #1a3a1a;
    --primary: #2d5a27;
    --primary-light: #4a7c59;
    --secondary: #6b9b5a;
    --accent: #98d182;
    --light: #e8f5e3;
    --white: #fafffe;
    --text: #1a2e1a;
    --text-light: #4a5a4a;
    
    /* 间距 */
    --space-xs: 0.5rem;
    --space-sm: 1rem;
    --space-md: 2rem;
    --space-lg: 4rem;
    --space-xl: 6rem;
}

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

html {
    scroll-behavior: smooth;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, 
                 "Helvetica Neue", Arial, "Noto Sans SC", sans-serif;
    line-height: 1.6;
    color: var(--text);
    background: var(--white);
}

/* 导航栏 */
nav {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: var(--space-sm) var(--space-md);
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    background: rgba(45, 90, 39, 0.95);
    backdrop-filter: blur(10px);
    z-index: 100;
}

.logo {
    font-size: 1.5rem;
    font-weight: bold;
    color: var(--white);
}

nav ul {
    display: flex;
    list-style: none;
    gap: var(--space-md);
}

nav a {
    color: var(--light);
    text-decoration: none;
    transition: color 0.3s ease;
    font-weight: 500;
}

nav a:hover {
    color: var(--accent);
}

/* Hero 区域 */
.hero {
    min-height: 100vh;
    background: linear-gradient(135deg, var(--primary-dark) 0%, var(--primary) 50%, var(--primary-light) 100%);
    display: flex;
    flex-direction: column;
    position: relative;
    overflow: hidden;
}

.hero::before {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    right: 0;
    height: 200px;
    background: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 1440 200'%3E%3Cpath fill='%23e8f5e3' d='M0,100 C200,150 400,50 600,100 C800,150 1000,50 1200,100 C1400,150 1440,100 1440,100 L1440,200 L0,200 Z'/%3E%3C/svg%3E");
    background-size: cover;
}

.hero-content {
    flex: 1;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    text-align: center;
    padding: var(--space-xl) var(--space-md);
    color: var(--white);
    position: relative;
    z-index: 1;
}

.hero h1 {
    font-size: clamp(2rem, 5vw, 4rem);
    margin-bottom: var(--space-sm);
    text-shadow: 2px 2px 4px rgba(0,0,0,0.2);
}

.hero p {
    font-size: 1.25rem;
    margin-bottom: var(--space-md);
    opacity: 0.9;
}

.cta-btn {
    display: inline-block;
    padding: var(--space-sm) var(--space-md);
    background: var(--accent);
    color: var(--primary-dark);
    text-decoration: none;
    border-radius: 50px;
    font-weight: bold;
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.cta-btn:hover {
    transform: translateY(-3px);
    box-shadow: 0 10px 30px rgba(0,0,0,0.2);
}

/* 统计区域 */
.stats {
    display: flex;
    justify-content: center;
    gap: var(--space-lg);
    padding: var(--space-lg) var(--space-md);
    background: var(--light);
    flex-wrap: wrap;
}

.stat-card {
    text-align: center;
    padding: var(--space-md);
}

.stat-number {
    display: block;
    font-size: 3rem;
    font-weight: bold;
    color: var(--primary);
}

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

/* 关于我们 */
.about {
    padding: var(--space-xl) var(--space-md);
    max-width: 1200px;
    margin: 0 auto;
}

.about h2 {
    text-align: center;
    font-size: 2rem;
    color: var(--primary);
    margin-bottom: var(--space-lg);
}

.about-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--space-lg);
    align-items: center;
}

.about-text p {
    margin-bottom: var(--space-sm);
    font-size: 1.1rem;
    color: var(--text-light);
}

.earth-svg {
    width: 200px;
    height: 200px;
    margin: 0 auto;
    display: block;
    animation: float 6s ease-in-out infinite;
}

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

/* 行动卡片 */
.actions {
    padding: var(--space-xl) var(--space-md);
    background: var(--light);
}

.actions h2 {
    text-align: center;
    font-size: 2rem;
    color: var(--primary);
    margin-bottom: var(--space-lg);
}

.action-cards {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: var(--space-md);
    max-width: 1200px;
    margin: 0 auto;
}

.action-card {
    background: var(--white);
    padding: var(--space-md);
    border-radius: 16px;
    box-shadow: 0 4px 20px rgba(45, 90, 39, 0.1);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.action-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 8px 30px rgba(45, 90, 39, 0.15);
}

.card-icon {
    font-size: 3rem;
    margin-bottom: var(--space-sm);
}

.action-card h3 {
    color: var(--primary);
    margin-bottom: var(--space-xs);
}

.action-card p {
    color: var(--text-light);
    margin-bottom: var(--space-sm);
}

.card-link {
    color: var(--primary);
    text-decoration: none;
    font-weight: 500;
    transition: color 0.3s ease;
}

.card-link:hover {
    color: var(--secondary);
}

/* 环保贴士 */
.tips {
    padding: var(--space-xl) var(--space-md);
    max-width: 800px;
    margin: 0 auto;
}

.tips h2 {
    text-align: center;
    font-size: 2rem;
    color: var(--primary);
    margin-bottom: var(--space-lg);
}

.tip-item {
    background: var(--white);
    border: 2px solid var(--light);
    border-radius: 12px;
    margin-bottom: var(--space-sm);
    overflow: hidden;
}

.tip-item summary {
    padding: var(--space-sm) var(--space-md);
    cursor: pointer;
    font-weight: 500;
    color: var(--primary);
    transition: background 0.3s ease;
}

.tip-item summary:hover {
    background: var(--light);
}

.tip-item p {
    padding: 0 var(--space-md) var(--space-md);
    color: var(--text-light);
}

/* 联系表单 */
.contact {
    padding: var(--space-xl) var(--space-md);
    background: var(--primary);
    color: var(--white);
}

.contact h2 {
    text-align: center;
    font-size: 2rem;
    margin-bottom: var(--space-lg);
}

.contact-form {
    max-width: 500px;
    margin: 0 auto;
}

.form-group {
    margin-bottom: var(--space-sm);
}

.form-group label {
    display: block;
    margin-bottom: var(--space-xs);
    font-weight: 500;
}

.form-group input,
.form-group textarea {
    width: 100%;
    padding: var(--space-sm);
    border: none;
    border-radius: 8px;
    font-size: 1rem;
    font-family: inherit;
}

.form-group input:focus,
.form-group textarea:focus {
    outline: 3px solid var(--accent);
}

.submit-btn {
    width: 100%;
    padding: var(--space-sm);
    background: var(--accent);
    color: var(--primary-dark);
    border: none;
    border-radius: 8px;
    font-size: 1rem;
    font-weight: bold;
    cursor: pointer;
    transition: background 0.3s ease, transform 0.3s ease;
}

.submit-btn:hover {
    background: var(--light);
    transform: scale(1.02);
}

/* 页脚 */
footer {
    background: var(--primary-dark);
    color: var(--light);
    padding: var(--space-lg) var(--space-md) var(--space-sm);
}

.footer-content {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: var(--space-md);
    max-width: 1200px;
    margin: 0 auto var(--space-md);
}

.footer-section h4 {
    margin-bottom: var(--space-sm);
    color: var(--accent);
}

.footer-section a {
    display: block;
    color: var(--light);
    text-decoration: none;
    margin-bottom: var(--space-xs);
    transition: color 0.3s ease;
}

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

.social-links {
    display: flex;
    gap: var(--space-sm);
    font-size: 1.5rem;
}

.social-links a {
    display: inline-block;
    transition: transform 0.3s ease;
}

.social-links a:hover {
    transform: scale(1.2);
}

.footer-bottom {
    text-align: center;
    padding-top: var(--space-md);
    border-top: 1px solid rgba(255,255,255,0.1);
}

.carbon-note {
    margin-top: var(--space-xs);
    font-size: 0.875rem;
    opacity: 0.8;
}

/* 响应式设计 */
@media (max-width: 768px) {
    nav ul {
        display: none;
    }
    
    .about-grid {
        grid-template-columns: 1fr;
        text-align: center;
    }
    
    .stats {
        gap: var(--space-md);
    }
    
    .stat-card {
        min-width: 150px;
    }
}

/* 减少动画 - 尊重用户偏好 */
@media (prefers-reduced-motion: reduce) {
    *, *::before, *::after {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
    }
    
    html {
        scroll-behavior: auto;
    }
}

/* 深色模式 - 更省电 */
@media (prefers-color-scheme: dark) {
    :root {
        --white: #1a2e1a;
        --light: #2d3d2d;
        --text: #e8f5e3;
        --text-light: #b8d4b0;
    }
    
    .action-card {
        background: var(--light);
    }
    
    .tip-item {
        background: var(--light);
        border-color: var(--primary-dark);
    }
}