/* ========================================
   星澈公益 - 样式表
   ======================================== */

/* CSS 变量 */
:root {
    --primary-color: #6366f1;
    --primary-light: #818cf8;
    --primary-dark: #4f46e5;
    --secondary-color: #ec4899;
    --secondary-light: #f472b6;
    --accent-color: #14b8a6;
    --text-dark: #1e293b;
    --text-gray: #64748b;
    --text-light: #94a3b8;
    --bg-light: #f8fafc;
    --bg-white: #ffffff;
    --border-color: #e2e8f0;
    --shadow-sm: 0 1px 2px 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);
    --gradient-primary: linear-gradient(135deg, var(--primary-color) 0%, var(--secondary-color) 100%);
    --gradient-dark: linear-gradient(135deg, #1e1b4b 0%, #312e81 100%);
    --transition-fast: 0.2s ease;
    --transition-normal: 0.3s ease;
    --transition-slow: 0.5s ease;
    --border-radius-sm: 8px;
    --border-radius-md: 12px;
    --border-radius-lg: 16px;
    --border-radius-xl: 24px;
}

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

html {
    scroll-behavior: smooth;
}

body {
    font-family: 'Noto Sans SC', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    font-size: 16px;
    line-height: 1.6;
    color: var(--text-dark);
    background-color: var(--bg-white);
    overflow-x: hidden;
}

a {
    text-decoration: none;
    color: inherit;
    transition: color var(--transition-fast);
}

ul {
    list-style: none;
}

img {
    max-width: 100%;
    height: auto;
}

/* 容器 */
.container {
    width: 100%;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

/* 按钮 */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    padding: 14px 28px;
    border: none;
    border-radius: var(--border-radius-md);
    font-size: 16px;
    font-weight: 500;
    cursor: pointer;
    transition: all var(--transition-normal);
}

.btn-primary {
    background: var(--gradient-primary);
    color: white;
    box-shadow: 0 4px 15px rgba(99, 102, 241, 0.4);
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(99, 102, 241, 0.5);
}

.btn-secondary {
    background: rgba(255, 255, 255, 0.15);
    color: white;
    border: 2px solid rgba(255, 255, 255, 0.3);
    backdrop-filter: blur(10px);
}

.btn-secondary:hover {
    background: rgba(255, 255, 255, 0.25);
    border-color: rgba(255, 255, 255, 0.5);
}

.btn-full {
    width: 100%;
}

/* ========================================
   导航栏
   ======================================== */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    background: transparent;
    transition: all var(--transition-normal);
}

.navbar.scrolled {
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    box-shadow: var(--shadow-md);
}

.nav-container {
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 80px;
}

.logo {
    display: flex;
    align-items: center;
    gap: 10px;
    font-size: 24px;
    font-weight: 700;
    color: white;
    transition: color var(--transition-normal);
}

.navbar.scrolled .logo {
    color: var(--primary-color);
}

.logo i {
    font-size: 28px;
}

.nav-menu {
    display: flex;
    align-items: center;
    gap: 8px;
}

.nav-menu a {
    padding: 10px 18px;
    border-radius: var(--border-radius-sm);
    font-size: 15px;
    font-weight: 500;
    color: rgba(255, 255, 255, 0.9);
    transition: all var(--transition-fast);
}

.navbar.scrolled .nav-menu a {
    color: var(--text-gray);
}

.nav-menu a:hover {
    background: rgba(255, 255, 255, 0.15);
    color: white;
}

.navbar.scrolled .nav-menu a:hover {
    background: var(--bg-light);
    color: var(--primary-color);
}

.nav-toggle {
    display: none;
    flex-direction: column;
    gap: 5px;
    cursor: pointer;
    padding: 5px;
}

.nav-toggle span {
    width: 25px;
    height: 3px;
    background: white;
    border-radius: 2px;
    transition: all var(--transition-normal);
}

.navbar.scrolled .nav-toggle span {
    background: var(--text-dark);
}

/* ========================================
   首屏区域
   ======================================== */
.hero {
    position: relative;
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--gradient-dark);
    overflow: hidden;
}

.hero-overlay {
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: url('data:image/svg+xml,<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 100 100"><defs><pattern id="grain" width="100" height="100" patternUnits="userSpaceOnUse"><circle cx="50" cy="50" r="1" fill="rgba(255,255,255,0.03)"/></pattern></defs><rect width="100" height="100" fill="url(%23grain)"/></svg>');
    pointer-events: none;
}

.hero-particles {
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    pointer-events: none;
}

.particle {
    position: absolute;
    width: 4px;
    height: 4px;
    background: rgba(255, 255, 255, 0.6);
    border-radius: 50%;
    animation: float 8s infinite ease-in-out;
}

@keyframes float {
    0%, 100% {
        transform: translateY(0) translateX(0);
        opacity: 0;
    }
    10% {
        opacity: 1;
    }
    90% {
        opacity: 1;
    }
    100% {
        transform: translateY(-100vh) translateX(20px);
        opacity: 0;
    }
}

.hero-content {
    position: relative;
    z-index: 10;
    text-align: center;
    padding: 100px 20px 60px;
}

.coming-soon-badge {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 10px 24px;
    background: rgba(255, 255, 255, 0.1);
    border: 1px solid rgba(255, 255, 255, 0.2);
    border-radius: 50px;
    color: white;
    font-size: 14px;
    font-weight: 500;
    margin-bottom: 30px;
    backdrop-filter: blur(10px);
    animation: pulse-glow 2s infinite;
}

@keyframes pulse-glow {
    0%, 100% {
        box-shadow: 0 0 20px rgba(99, 102, 241, 0.3);
    }
    50% {
        box-shadow: 0 0 30px rgba(99, 102, 241, 0.5);
    }
}

.hero-title {
    font-size: clamp(36px, 8vw, 72px);
    font-weight: 700;
    color: white;
    line-height: 1.2;
    margin-bottom: 24px;
}

.title-line {
    display: block;
    font-size: clamp(24px, 5vw, 42px);
    font-weight: 400;
    opacity: 0.9;
    margin-bottom: 10px;
}

.title-highlight {
    display: block;
    background: linear-gradient(135deg, #fff 0%, #a5b4fc 50%, #f0abfc 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.hero-subtitle {
    font-size: clamp(16px, 2.5vw, 20px);
    color: rgba(255, 255, 255, 0.8);
    max-width: 600px;
    margin: 0 auto 40px;
    line-height: 1.8;
}

.hero-buttons {
    display: flex;
    justify-content: center;
    gap: 16px;
    flex-wrap: wrap;
    margin-bottom: 60px;
}

.countdown-section {
    margin-top: 40px;
}

.countdown-label {
    color: rgba(255, 255, 255, 0.7);
    font-size: 14px;
    margin-bottom: 20px;
    text-transform: uppercase;
    letter-spacing: 2px;
}

.countdown-timer {
    display: flex;
    justify-content: center;
    gap: 20px;
}

.countdown-item {
    display: flex;
    flex-direction: column;
    align-items: center;
    padding: 20px;
    background: rgba(255, 255, 255, 0.1);
    border-radius: var(--border-radius-md);
    min-width: 80px;
    backdrop-filter: blur(10px);
}

.countdown-number {
    font-size: 36px;
    font-weight: 700;
    color: white;
    line-height: 1;
}

.countdown-text {
    font-size: 12px;
    color: rgba(255, 255, 255, 0.7);
    margin-top: 8px;
    text-transform: uppercase;
    letter-spacing: 1px;
}

.scroll-indicator {
    position: absolute;
    bottom: 30px;
    left: 50%;
    transform: translateX(-50%);
    animation: bounce 2s infinite;
}

.scroll-indicator a {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 40px;
    height: 40px;
    border: 2px solid rgba(255, 255, 255, 0.3);
    border-radius: 50%;
    color: rgba(255, 255, 255, 0.7);
    transition: all var(--transition-normal);
}

.scroll-indicator a:hover {
    border-color: white;
    color: white;
}

@keyframes bounce {
    0%, 20%, 50%, 80%, 100% {
        transform: translateX(-50%) translateY(0);
    }
    40% {
        transform: translateX(-50%) translateY(-10px);
    }
    60% {
        transform: translateX(-50%) translateY(-5px);
    }
}

/* ========================================
   通用section样式
   ======================================== */
.section {
    padding: 100px 0;
}

.section-header {
    text-align: center;
    margin-bottom: 60px;
}

.section-header.light .section-title,
.section-header.light .section-desc {
    color: white;
}

.section-tag {
    display: inline-block;
    padding: 6px 16px;
    background: rgba(99, 102, 241, 0.1);
    color: var(--primary-color);
    font-size: 14px;
    font-weight: 600;
    border-radius: 50px;
    margin-bottom: 16px;
}

.section-header.light .section-tag {
    background: rgba(255, 255, 255, 0.15);
    color: white;
}

.section-title {
    font-size: clamp(28px, 5vw, 42px);
    font-weight: 700;
    color: var(--text-dark);
    margin-bottom: 16px;
}

.section-desc {
    font-size: 18px;
    color: var(--text-gray);
    max-width: 600px;
    margin: 0 auto;
}

/* ========================================
   关于我们
   ======================================== */
.about-section {
    background: var(--bg-light);
}

.about-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
    gap: 24px;
}

.about-card {
    background: white;
    padding: 40px 30px;
    border-radius: var(--border-radius-lg);
    text-align: center;
    transition: all var(--transition-normal);
    box-shadow: var(--shadow-sm);
}

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

.about-icon {
    width: 80px;
    height: 80px;
    margin: 0 auto 24px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--gradient-primary);
    border-radius: 50%;
    font-size: 32px;
    color: white;
}

.about-card h3 {
    font-size: 20px;
    font-weight: 600;
    color: var(--text-dark);
    margin-bottom: 12px;
}

.about-card p {
    font-size: 15px;
    color: var(--text-gray);
    line-height: 1.7;
}

/* ========================================
   疾病科普
   ======================================== */
.diseases-section {
    background: white;
}

.disease-card {
    background: white;
    border-radius: var(--border-radius-xl);
    overflow: hidden;
    margin-bottom: 40px;
    box-shadow: var(--shadow-lg);
    border: 1px solid var(--border-color);
}

.disease-header {
    display: flex;
    align-items: center;
    gap: 20px;
    padding: 30px;
    background: linear-gradient(135deg, var(--bg-light) 0%, white 100%);
    border-bottom: 1px solid var(--border-color);
}

.disease-icon {
    width: 70px;
    height: 70px;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: var(--border-radius-md);
    font-size: 28px;
    color: white;
    flex-shrink: 0;
}

.alcohol-icon {
    background: linear-gradient(135deg, #f59e0b 0%, #d97706 100%);
}

.arthritis-icon {
    background: linear-gradient(135deg, #14b8a6 0%, #0d9488 100%);
}

.disease-title-area {
    flex: 1;
}

.disease-name {
    font-size: 26px;
    font-weight: 700;
    color: var(--text-dark);
    margin-bottom: 4px;
}

.disease-tag {
    font-size: 14px;
    color: var(--text-light);
    font-style: italic;
}

.disease-content {
    padding: 30px;
}

.disease-intro {
    margin-bottom: 30px;
}

.disease-intro h4,
.symptoms-category h4,
.disease-tips h4 {
    display: flex;
    align-items: center;
    gap: 10px;
    font-size: 18px;
    font-weight: 600;
    color: var(--text-dark);
    margin-bottom: 16px;
}

.disease-intro h4 i,
.symptoms-category h4 i,
.disease-tips h4 i {
    color: var(--primary-color);
}

.disease-intro p,
.disease-tips p {
    font-size: 16px;
    color: var(--text-gray);
    line-height: 1.8;
}

.symptoms-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 30px;
    margin-bottom: 30px;
}

.symptoms-category {
    background: var(--bg-light);
    padding: 24px;
    border-radius: var(--border-radius-md);
}

.symptoms-list {
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.symptoms-list li {
    display: flex;
    align-items: flex-start;
    gap: 12px;
    font-size: 15px;
    color: var(--text-gray);
    line-height: 1.6;
}

.symptom-bullet {
    width: 8px;
    height: 8px;
    background: var(--primary-color);
    border-radius: 50%;
    flex-shrink: 0;
    margin-top: 7px;
}

.disease-tips {
    background: linear-gradient(135deg, rgba(99, 102, 241, 0.05) 0%, rgba(236, 72, 153, 0.05) 100%);
    padding: 24px;
    border-radius: var(--border-radius-md);
    border-left: 4px solid var(--primary-color);
}

.disease-tips h4 i {
    color: #f59e0b;
}

.more-diseases {
    background: var(--bg-light);
    border-radius: var(--border-radius-xl);
    padding: 60px;
    text-align: center;
    border: 2px dashed var(--border-color);
}

.more-diseases-content i {
    font-size: 48px;
    color: var(--primary-light);
    margin-bottom: 20px;
}

.more-diseases-content h4 {
    font-size: 24px;
    font-weight: 600;
    color: var(--text-dark);
    margin-bottom: 12px;
}

.more-diseases-content p {
    font-size: 16px;
    color: var(--text-gray);
}

/* ========================================
   使命愿景
   ======================================== */
.mission-section {
    background: var(--gradient-dark);
    position: relative;
    overflow: hidden;
}

.mission-section::before {
    content: '';
    position: absolute;
    top: -50%;
    right: -20%;
    width: 600px;
    height: 600px;
    background: radial-gradient(circle, rgba(99, 102, 241, 0.3) 0%, transparent 70%);
    border-radius: 50%;
}

.mission-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 30px;
    position: relative;
    z-index: 1;
}

.mission-item {
    padding: 40px 30px;
    background: rgba(255, 255, 255, 0.05);
    border-radius: var(--border-radius-lg);
    backdrop-filter: blur(10px);
    border: 1px solid rgba(255, 255, 255, 0.1);
    transition: all var(--transition-normal);
}

.mission-item:hover {
    background: rgba(255, 255, 255, 0.1);
    transform: translateY(-5px);
}

.mission-number {
    font-size: 48px;
    font-weight: 800;
    background: linear-gradient(135deg, rgba(255, 255, 255, 0.3) 0%, rgba(255, 255, 255, 0.1) 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    margin-bottom: 20px;
}

.mission-item h3 {
    font-size: 22px;
    font-weight: 600;
    color: white;
    margin-bottom: 16px;
}

.mission-item p {
    font-size: 15px;
    color: rgba(255, 255, 255, 0.7);
    line-height: 1.8;
}

/* ========================================
   捐赠支持
   ======================================== */
.donate-section {
    background: var(--bg-light);
}

.donate-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 30px;
    margin-bottom: 40px;
}

.donate-card {
    background: white;
    padding: 40px 30px;
    border-radius: var(--border-radius-lg);
    text-align: center;
    box-shadow: var(--shadow-md);
    position: relative;
    transition: all var(--transition-normal);
}

.donate-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-xl);
}

.donate-icon {
    width: 80px;
    height: 80px;
    margin: 0 auto 24px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--gradient-primary);
    border-radius: 50%;
    font-size: 32px;
    color: white;
}

.donate-card h3 {
    font-size: 22px;
    font-weight: 600;
    color: var(--text-dark);
    margin-bottom: 16px;
}

.donate-card > p {
    font-size: 15px;
    color: var(--text-gray);
    line-height: 1.7;
    margin-bottom: 24px;
}

.donate-info {
    background: var(--bg-light);
    padding: 20px;
    border-radius: var(--border-radius-md);
    text-align: left;
}

.donate-info p {
    font-size: 14px;
    color: var(--text-gray);
    margin-bottom: 8px;
}

.donate-info p:last-child {
    margin-bottom: 0;
}

.donate-info strong {
    color: var(--text-dark);
}

.volunteer-list {
    text-align: left;
    margin-bottom: 20px;
}

.volunteer-list li {
    display: flex;
    align-items: center;
    gap: 10px;
    padding: 10px 0;
    font-size: 15px;
    color: var(--text-gray);
    border-bottom: 1px solid var(--border-color);
}

.volunteer-list li:last-child {
    border-bottom: none;
}

.volunteer-list li i {
    color: var(--accent-color);
}

.coming-soon-tag {
    display: inline-block;
    padding: 8px 20px;
    background: linear-gradient(135deg, #fef3c7 0%, #fde68a 100%);
    color: #92400e;
    font-size: 14px;
    font-weight: 600;
    border-radius: 50px;
    margin-top: 20px;
}

.share-buttons {
    display: flex;
    justify-content: center;
    gap: 16px;
    margin-bottom: 16px;
}

.share-btn {
    width: 50px;
    height: 50px;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: 50%;
    font-size: 22px;
    color: white;
    transition: all var(--transition-normal);
}

.share-btn.wechat {
    background: #07c160;
}

.share-btn.weibo {
    background: #e6162d;
}

.share-btn.qq {
    background: #12b7f5;
}

.share-btn:hover {
    transform: scale(1.1);
    box-shadow: var(--shadow-lg);
}

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

.donate-notice {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 12px;
    padding: 20px;
    background: rgba(99, 102, 241, 0.1);
    border-radius: var(--border-radius-md);
    color: var(--primary-dark);
}

.donate-notice i {
    font-size: 24px;
}

.donate-notice p {
    font-size: 15px;
    margin: 0;
}

/* ========================================
   联系我们
   ======================================== */
.contact-section {
    background: white;
}

.contact-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 60px;
    align-items: start;
}

.contact-info {
    display: flex;
    flex-direction: column;
    gap: 30px;
}

.contact-item {
    display: flex;
    gap: 20px;
    align-items: flex-start;
}

.contact-icon {
    width: 60px;
    height: 60px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--gradient-primary);
    border-radius: var(--border-radius-md);
    font-size: 24px;
    color: white;
    flex-shrink: 0;
}

.contact-details h4 {
    font-size: 18px;
    font-weight: 600;
    color: var(--text-dark);
    margin-bottom: 4px;
}

.contact-details p {
    font-size: 16px;
    color: var(--text-gray);
    margin-bottom: 4px;
}

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

.contact-form-container {
    background: var(--bg-light);
    padding: 40px;
    border-radius: var(--border-radius-xl);
}

.contact-form-container h3 {
    font-size: 20px;
    font-weight: 600;
    color: var(--text-dark);
    margin-bottom: 30px;
}

.contact-form {
    display: flex;
    flex-direction: column;
    gap: 20px;
}

.form-group {
    display: flex;
    flex-direction: column;
    gap: 8px;
}

.form-group label {
    font-size: 14px;
    font-weight: 500;
    color: var(--text-dark);
}

.form-group input,
.form-group select,
.form-group textarea {
    padding: 14px 18px;
    border: 2px solid var(--border-color);
    border-radius: var(--border-radius-md);
    font-size: 16px;
    font-family: inherit;
    transition: all var(--transition-fast);
    background: white;
}

.form-group input:focus,
.form-group select:focus,
.form-group textarea:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(99, 102, 241, 0.1);
}

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

/* ========================================
   页脚
   ======================================== */
.footer {
    background: var(--text-dark);
    color: white;
    padding-top: 80px;
}

.footer-top {
    display: grid;
    grid-template-columns: 1fr 2fr;
    gap: 60px;
    padding-bottom: 60px;
    border-bottom: 1px solid rgba(255, 255, 255, 0.1);
}

.footer-brand .logo {
    margin-bottom: 20px;
}

.footer-brand > p {
    font-size: 15px;
    color: rgba(255, 255, 255, 0.7);
    line-height: 1.8;
    margin-bottom: 24px;
}

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

.footer-social a {
    width: 44px;
    height: 44px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: rgba(255, 255, 255, 0.1);
    border-radius: 50%;
    font-size: 18px;
    color: white;
    transition: all var(--transition-normal);
}

.footer-social a:hover {
    background: var(--primary-color);
    transform: translateY(-3px);
}

.footer-links {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 40px;
}

.footer-column h4 {
    font-size: 16px;
    font-weight: 600;
    margin-bottom: 20px;
}

.footer-column ul {
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.footer-column a {
    font-size: 14px;
    color: rgba(255, 255, 255, 0.7);
    transition: all var(--transition-fast);
}

.footer-column a:hover {
    color: white;
    padding-left: 5px;
}

.footer-bottom {
    padding: 30px 0;
    text-align: center;
}

.footer-bottom p {
    font-size: 14px;
    color: rgba(255, 255, 255, 0.6);
    margin-bottom: 8px;
}

.footer-bottom .disclaimer {
    font-size: 12px;
    color: rgba(255, 255, 255, 0.4);
}

/* ========================================
   回到顶部
   ======================================== */
.back-to-top {
    position: fixed;
    bottom: 30px;
    right: 30px;
    width: 50px;
    height: 50px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--gradient-primary);
    color: white;
    border-radius: 50%;
    font-size: 20px;
    box-shadow: var(--shadow-lg);
    opacity: 0;
    visibility: hidden;
    transform: translateY(20px);
    transition: all var(--transition-normal);
    z-index: 999;
}

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

.back-to-top:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-xl);
}

/* ========================================
   响应式设计
   ======================================== */
@media (max-width: 992px) {
    .footer-top {
        grid-template-columns: 1fr;
        gap: 40px;
    }

    .footer-links {
        grid-template-columns: repeat(3, 1fr);
    }
}

@media (max-width: 768px) {
    .nav-toggle {
        display: flex;
    }

    .nav-menu {
        position: fixed;
        top: 80px;
        left: 0;
        right: 0;
        background: white;
        flex-direction: column;
        padding: 20px;
        gap: 0;
        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 a {
        color: var(--text-dark);
        padding: 15px;
        border-radius: 0;
        border-bottom: 1px solid var(--border-color);
    }

    .nav-menu a:hover {
        background: var(--bg-light);
        color: var(--primary-color);
    }

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

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

    .countdown-timer {
        gap: 10px;
    }

    .countdown-item {
        padding: 15px 10px;
        min-width: 60px;
    }

    .countdown-number {
        font-size: 24px;
    }

    .disease-header {
        flex-direction: column;
        text-align: center;
    }

    .contact-form-container {
        padding: 30px 20px;
    }

    .footer-links {
        grid-template-columns: 1fr 1fr;
        gap: 30px;
    }

    .back-to-top {
        bottom: 20px;
        right: 20px;
        width: 44px;
        height: 44px;
    }
}

@media (max-width: 480px) {
    .section {
        padding: 60px 0;
    }

    .section-title {
        font-size: 24px;
    }

    .about-card,
    .donate-card {
        padding: 30px 20px;
    }

    .disease-content {
        padding: 20px;
    }

    .symptoms-category {
        padding: 20px;
    }

    .more-diseases {
        padding: 40px 20px;
    }

    .mission-item {
        padding: 30px 20px;
    }

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

/* ========================================
   动画效果
   ======================================== */
.fade-in {
    opacity: 0;
    transform: translateY(30px);
    transition: all 0.6s ease-out;
}

.fade-in.visible {
    opacity: 1;
    transform: translateY(0);
}

/* 表单提交成功提示 */
.form-success {
    display: none;
    padding: 20px;
    background: linear-gradient(135deg, rgba(20, 184, 166, 0.1) 0%, rgba(20, 184, 166, 0.05) 100%);
    border: 1px solid var(--accent-color);
    border-radius: var(--border-radius-md);
    text-align: center;
    color: var(--accent-color);
}

.form-success.show {
    display: block;
    animation: fadeIn 0.3s ease-out;
}

.form-success i {
    font-size: 48px;
    margin-bottom: 16px;
}

.form-success h4 {
    font-size: 20px;
    font-weight: 600;
    margin-bottom: 8px;
}

.form-success p {
    font-size: 15px;
    opacity: 0.9;
}

@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(-10px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}