/* 基础样式重置 */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

/* 根变量 */
:root {
    --primary-color: #4f46e5;
    --primary-dark: #3730a3;
    --secondary-color: #06b6d4;
    --accent-color: #f59e0b;
    --success-color: #10b981;
    --warning-color: #f59e0b;
    --error-color: #ef4444;
    
    --text-primary: #1f2937;
    --text-secondary: #6b7280;
    --text-light: #9ca3af;
    
    --bg-primary: #ffffff;
    --bg-secondary: #f9fafb;
    --bg-tertiary: #f3f4f6;
    
    --border-color: #e5e7eb;
    --border-light: #f3f4f6;
    
    --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.05);
    --shadow-md: 0 4px 6px -1px rgb(0 0 0 / 0.1), 0 2px 4px -2px rgb(0 0 0 / 0.1);
    --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.1), 0 4px 6px -4px rgb(0 0 0 / 0.1);
    --shadow-xl: 0 20px 25px -5px rgb(0 0 0 / 0.1), 0 8px 10px -6px rgb(0 0 0 / 0.1);
    
    --radius-sm: 0.375rem;
    --radius-md: 0.5rem;
    --radius-lg: 0.75rem;
    --radius-xl: 1rem;
    
    --font-family: 'Noto Sans SC', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
}

/* 基础样式 */
body {
    font-family: var(--font-family);
    line-height: 1.6;
    color: var(--text-primary);
    background-color: var(--bg-primary);
}

/* 导航栏 */
.navbar {
    background: var(--bg-primary);
    box-shadow: var(--shadow-sm);
    position: sticky;
    top: 0;
    z-index: 1000;
    border-bottom: 1px solid var(--border-color);
}

.nav-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 1rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
    height: 70px;
}

.nav-logo h2 {
    color: var(--primary-color);
    font-size: 1.5rem;
    font-weight: 700;
}

.nav-menu {
    display: flex;
    list-style: none;
    gap: 2rem;
}

.nav-link {
    text-decoration: none;
    color: var(--text-secondary);
    font-weight: 500;
    transition: color 0.3s ease;
    position: relative;
}

.nav-link:hover,
.nav-link.active {
    color: var(--primary-color);
}

.nav-link.active::after {
    content: '';
    position: absolute;
    bottom: -5px;
    left: 0;
    right: 0;
    height: 2px;
    background: var(--primary-color);
    border-radius: 1px;
}

.hamburger {
    display: none;
    flex-direction: column;
    cursor: pointer;
}

.bar {
    width: 25px;
    height: 3px;
    background: var(--text-primary);
    margin: 3px 0;
    transition: 0.3s;
}

/* 语言切换器 */
.language-switcher {
    display: flex;
    gap: 0.5rem;
    align-items: center;
}

.lang-btn {
    padding: 0.5rem 1rem;
    border: 1px solid var(--border-color);
    background: var(--bg-primary);
    color: var(--text-secondary);
    border-radius: var(--radius-md);
    cursor: pointer;
    font-size: 0.875rem;
    transition: all 0.3s ease;
}

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

.lang-btn.active {
    background: var(--primary-color);
    color: white;
    border-color: var(--primary-color);
}

/* 按钮样式 */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 0.75rem 1.5rem;
    border: none;
    border-radius: var(--radius-md);
    font-weight: 500;
    text-decoration: none;
    cursor: pointer;
    transition: all 0.3s ease;
    font-size: 1rem;
    min-height: 44px;
}

.btn-primary {
    background: var(--primary-color);
    color: white;
}

.btn-primary:hover {
    background: var(--primary-dark);
    transform: translateY(-1px);
    box-shadow: var(--shadow-md);
}

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

.btn-secondary:hover {
    background: var(--bg-tertiary);
    transform: translateY(-1px);
}

.btn-share {
    background: var(--success-color);
    color: white;
    padding: 0.5rem 1rem;
    font-size: 0.875rem;
}

.btn-donate {
    background: var(--accent-color);
    color: white;
    padding: 0.5rem 1rem;
    font-size: 0.875rem;
}

/* 主页样式 */
.hero {
    background: linear-gradient(135deg, var(--primary-color) 0%, var(--secondary-color) 100%);
    color: white;
    padding: 4rem 0;
    text-align: center;
}

.hero-content {
    max-width: 800px;
    margin: 0 auto;
    padding: 0 1rem;
}

.hero-title {
    font-size: 3rem;
    font-weight: 700;
    margin-bottom: 1rem;
    line-height: 1.2;
}

.hero-subtitle {
    font-size: 1.25rem;
    margin-bottom: 2rem;
    opacity: 0.9;
}

.hero-buttons {
    display: flex;
    gap: 1rem;
    justify-content: center;
    flex-wrap: wrap;
}

.hero-image {
    margin-top: 3rem;
}

.pet-illustration {
    display: flex;
    justify-content: center;
    gap: 2rem;
    flex-wrap: wrap;
}

.pet-card {
    background: rgba(255, 255, 255, 0.1);
    border-radius: var(--radius-lg);
    padding: 1.5rem;
    text-align: center;
    backdrop-filter: blur(10px);
    border: 1px solid rgba(255, 255, 255, 0.2);
    transition: all 0.3s ease;
}

.pet-card:hover {
    transform: translateY(-5px);
    background: rgba(255, 255, 255, 0.2);
    box-shadow: var(--shadow-lg);
    cursor: pointer;
}

.pet-avatar {
    font-size: 3rem;
    margin-bottom: 1rem;
}

/* 特色功能 */
.features {
    padding: 4rem 0;
    background: var(--bg-secondary);
}

.section-title {
    text-align: center;
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: 3rem;
    color: var(--text-primary);
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 2rem;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 1rem;
}

.feature-card {
    background: var(--bg-primary);
    padding: 2rem;
    border-radius: var(--radius-lg);
    text-align: center;
    box-shadow: var(--shadow-md);
    transition: transform 0.3s ease;
}

.feature-card:hover {
    transform: translateY(-5px);
}

.feature-icon {
    font-size: 3rem;
    margin-bottom: 1rem;
}

.feature-card h3 {
    font-size: 1.25rem;
    font-weight: 600;
    margin-bottom: 1rem;
    color: var(--text-primary);
}

/* 统计区域 */
.stats {
    padding: 3rem 0;
    background: var(--primary-color);
    color: white;
}

.stats-container {
    display: flex;
    justify-content: space-around;
    max-width: 800px;
    margin: 0 auto;
    padding: 0 1rem;
    flex-wrap: wrap;
    gap: 2rem;
}

.stat-item {
    text-align: center;
}

.stat-item h3 {
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: 0.5rem;
}

/* 计算器页面样式 */
.calculator-main {
    padding: 2rem 0;
    background: var(--bg-secondary);
    min-height: calc(100vh - 70px);
}

.calculator-container {
    max-width: 800px;
    margin: 0 auto;
    padding: 0 1rem;
}

.calculator-title {
    text-align: center;
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: 0.5rem;
    color: var(--text-primary);
}

.calculator-subtitle {
    text-align: center;
    color: var(--text-secondary);
    margin-bottom: 3rem;
    font-size: 1.125rem;
}

.calculator-form {
    background: var(--bg-primary);
    padding: 2rem;
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-lg);
    margin-bottom: 2rem;
}

.form-group {
    margin-bottom: 2rem;
}

.form-group label {
    display: block;
    margin-bottom: 0.5rem;
    font-weight: 600;
    color: var(--text-primary);
}

.pet-type-selector {
    display: flex;
    gap: 1rem;
    flex-wrap: wrap;
}

.pet-type-option {
    flex: 1;
    min-width: 120px;
    padding: 1.5rem;
    border: 2px solid var(--border-color);
    border-radius: var(--radius-md);
    text-align: center;
    cursor: pointer;
    transition: all 0.3s ease;
}

.pet-type-option:hover {
    border-color: var(--primary-color);
    background: var(--bg-secondary);
}

.pet-type-option.selected {
    border-color: var(--primary-color);
    background: var(--primary-color);
    color: white;
}

.pet-icon {
    font-size: 2rem;
    margin-bottom: 0.5rem;
}

.age-input-group {
    display: flex;
    gap: 1rem;
}

/* 输入方式切换样式 */
.input-mode-switch {
    display: flex;
    background: var(--bg-tertiary);
    border-radius: var(--radius-md);
    padding: 0.25rem;
    margin-bottom: 1rem;
    gap: 0.25rem;
}

.mode-btn {
    flex: 1;
    padding: 0.5rem 1rem;
    border: none;
    background: transparent;
    color: var(--text-secondary);
    font-weight: 500;
    border-radius: var(--radius-sm);
    cursor: pointer;
    transition: all 0.3s ease;
    font-size: 0.875rem;
}

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

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

.age-input-container,
.birthday-input-container {
    transition: all 0.3s ease;
}

.birthday-input-group {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.birthday-input-wrapper {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.birthday-input-wrapper label {
    font-weight: 500;
    color: var(--text-primary);
    font-size: 0.875rem;
}

.date-input-container {
    position: relative;
    cursor: pointer;
}

.date-input-container input[type="date"] {
    width: 100%;
    padding: 0.75rem;
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    font-size: 1rem;
    transition: border-color 0.3s ease;
    background: var(--bg-primary);
    cursor: pointer;
    text-align: left;
    font-family: var(--font-family);
}

.date-input-container input[type="date"]:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgb(79 70 229 / 0.1);
}

.date-input-overlay {
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    cursor: pointer;
    z-index: 1;
}

.date-input-overlay:hover {
    background: rgba(79, 70, 229, 0.05);
    border-radius: var(--radius-md);
}



.age-input {
    flex: 1;
    position: relative;
}

.age-input input,
.age-input select {
    width: 100%;
    padding: 0.75rem;
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    font-size: 1rem;
    transition: border-color 0.3s ease;
    background: var(--bg-primary);
}

.age-input select {
    cursor: pointer;
    appearance: none;
    background-image: url("data:image/svg+xml,%3csvg xmlns='http://www.w3.org/2000/svg' fill='none' viewBox='0 0 20 20'%3e%3cpath stroke='%236b7280' stroke-linecap='round' stroke-linejoin='round' stroke-width='1.5' d='m6 8 4 4 4-4'/%3e%3c/svg%3e");
    background-position: right 0.5rem center;
    background-repeat: no-repeat;
    background-size: 1.5em 1.5em;
    padding-right: 2.5rem;
}

.age-input select:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgb(79 70 229 / 0.1);
}

.age-input label {
    position: absolute;
    top: -0.5rem;
    left: 0.75rem;
    background: var(--bg-primary);
    padding: 0 0.25rem;
    font-size: 0.875rem;
    color: var(--text-secondary);
}

select {
    width: 100%;
    padding: 0.75rem;
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    font-size: 1rem;
    background: var(--bg-primary);
}

.btn-calculate {
    width: 100%;
    font-size: 1.125rem;
    padding: 1rem;
}

/* 结果显示 */
.result-section {
    margin-top: 3rem;
    margin-bottom: 2rem;
}

.result-card {
    background: var(--bg-primary);
    padding: 2rem;
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-lg);
}

.result-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 2rem;
    padding-bottom: 1rem;
    border-bottom: 1px solid var(--border-color);
}

.pet-result-icon {
    font-size: 3rem;
}

.age-comparison {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 2rem;
    padding: 2rem;
    background: var(--bg-secondary);
    border-radius: var(--radius-md);
}

.age-arrow {
    font-size: 2rem;
    color: var(--primary-color);
    font-weight: bold;
}

.age-display {
    font-size: 2rem;
    font-weight: 700;
    color: var(--primary-color);
}

.age-details {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 1rem;
    margin-bottom: 2rem;
}

.detail-item {
    display: flex;
    justify-content: space-between;
    padding: 0.75rem;
    background: var(--bg-secondary);
    border-radius: var(--radius-md);
}

.detail-label {
    font-weight: 500;
    color: var(--text-secondary);
}

.detail-value {
    font-weight: 600;
    color: var(--text-primary);
}

.health-advice {
    margin-bottom: 2rem;
    padding: 1.5rem;
    background: linear-gradient(135deg, var(--success-color) 0%, #059669 100%);
    color: white;
    border-radius: var(--radius-md);
}

.health-advice h3 {
    margin-bottom: 1rem;
}

.advice-content ul {
    list-style: none;
    padding-left: 0;
}

.advice-content li {
    padding: 0.5rem 0;
    border-bottom: 1px solid rgba(255, 255, 255, 0.2);
}

.advice-content li:last-child {
    border-bottom: none;
}

.share-result {
    margin-top: 2rem;
    padding-top: 2rem;
    border-top: 1px solid var(--border-color);
}

.share-buttons {
    display: flex;
    gap: 1rem;
    flex-wrap: wrap;
}

/* 历史记录区域样式 */
.history-section {
    margin-top: 4rem;
    padding-top: 3rem;
    border-top: 2px solid var(--border-light);
}

.history-section h3 {
    font-size: 1.5rem;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 1.5rem;
    text-align: center;
    position: relative;
}

.history-section h3::after {
    content: '';
    position: absolute;
    bottom: -0.5rem;
    left: 50%;
    transform: translateX(-50%);
    width: 60px;
    height: 3px;
    background: linear-gradient(90deg, var(--primary-color), var(--secondary-color));
    border-radius: 2px;
}

.history-list {
    max-width: 800px;
    margin: 0 auto;
}

.history-item {
    background: var(--bg-primary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    padding: 1rem;
    margin-bottom: 1rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
    transition: all 0.3s ease;
    box-shadow: var(--shadow-sm);
}

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

.history-pet-info {
    display: flex;
    align-items: center;
    gap: 1rem;
    flex: 1;
}

.history-icon {
    font-size: 1.5rem;
    width: 40px;
    height: 40px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--bg-secondary);
    border-radius: 50%;
}

.history-details {
    flex: 1;
}

.history-age {
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 0.25rem;
}

.history-time {
    font-size: 0.875rem;
    color: var(--text-secondary);
}

.history-redo {
    background: var(--primary-color);
    color: white;
    border: none;
    padding: 0.5rem 1rem;
    border-radius: var(--radius-sm);
    font-size: 0.875rem;
    font-weight: 500;
    cursor: pointer;
    transition: background-color 0.3s ease;
}

.history-redo:hover {
    background: var(--primary-dark);
}

.no-history {
    text-align: center;
    color: var(--text-secondary);
    font-style: italic;
    padding: 2rem;
}

/* 指南页面样式 */
.guide-main {
    padding: 2rem 0;
    background: var(--bg-secondary);
}

.guide-container {
    max-width: 1000px;
    margin: 0 auto;
    padding: 0 1rem;
}

.guide-title {
    text-align: center;
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: 0.5rem;
    color: var(--text-primary);
}

.guide-subtitle {
    text-align: center;
    color: var(--text-secondary);
    margin-bottom: 3rem;
    font-size: 1.125rem;
}

.guide-section {
    background: var(--bg-primary);
    margin-bottom: 2rem;
    padding: 2rem;
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-md);
}

.guide-section h2 {
    font-size: 1.75rem;
    font-weight: 600;
    margin-bottom: 1.5rem;
    color: var(--text-primary);
}

.content-card {
    background: var(--bg-secondary);
    padding: 1.5rem;
    border-radius: var(--radius-md);
    margin-bottom: 1.5rem;
}

.content-card ul {
    margin-top: 1rem;
    padding-left: 1.5rem;
}

.content-card li {
    margin-bottom: 0.5rem;
}

.age-table-container {
    overflow-x: auto;
    margin: 1.5rem 0;
}

.age-table {
    width: 100%;
    border-collapse: collapse;
    background: var(--bg-primary);
    border-radius: var(--radius-md);
    overflow: hidden;
    box-shadow: var(--shadow-sm);
}

.age-table th,
.age-table td {
    padding: 1rem;
    text-align: left;
    border-bottom: 1px solid var(--border-color);
}

.age-table th {
    background: var(--primary-color);
    color: white;
    font-weight: 600;
}

.age-table tr:hover {
    background: var(--bg-secondary);
}

.breed-info-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 1rem;
    margin: 1.5rem 0;
}

.breed-card {
    background: var(--bg-secondary);
    padding: 1rem;
    border-radius: var(--radius-md);
    text-align: center;
    border: 1px solid var(--border-color);
}

.breed-icon {
    font-size: 2rem;
    margin-bottom: 0.75rem;
}

.breed-card h3 {
    font-size: 1.125rem;
    font-weight: 600;
    margin-bottom: 0.75rem;
    color: var(--text-primary);
}

.breed-card p {
    margin-bottom: 0.25rem;
    color: var(--text-secondary);
    font-size: 0.875rem;
}

.health-tips-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 1rem;
    margin: 1.5rem 0;
}

/* 让第4和第5个卡片占据第二排 */
.health-tips-grid .tip-card:nth-child(4),
.health-tips-grid .tip-card:nth-child(5) {
    grid-column: span 1.5;
}

.tip-card {
    background: var(--bg-secondary);
    padding: 1rem;
    border-radius: var(--radius-md);
    border-left: 4px solid var(--success-color);
}

.tip-card h3 {
    font-size: 1rem;
    font-weight: 600;
    margin-bottom: 0.75rem;
    color: var(--text-primary);
}

.tip-card ul {
    list-style: none;
    padding-left: 0;
}

.tip-card li {
    padding: 0.25rem 0;
    border-bottom: 1px solid var(--border-color);
    font-size: 0.875rem;
}

.tip-card li:last-child {
    border-bottom: none;
}

/* FAQ 页面样式 */
.faq-main {
    padding: 2rem 0;
    background: var(--bg-secondary);
}

.faq-container {
    max-width: 800px;
    margin: 0 auto;
    padding: 0 1rem;
}

.faq-title {
    text-align: center;
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: 0.5rem;
    color: var(--text-primary);
}

.faq-subtitle {
    text-align: center;
    color: var(--text-secondary);
    margin-bottom: 3rem;
    font-size: 1.125rem;
}

.faq-search {
    display: flex;
    margin-bottom: 2rem;
    gap: 0.5rem;
}

.search-input {
    flex: 1;
    padding: 0.75rem;
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    font-size: 1rem;
}

.search-btn {
    padding: 0.75rem 1rem;
    background: var(--primary-color);
    color: white;
    border: none;
    border-radius: var(--radius-md);
    cursor: pointer;
}

.faq-categories {
    display: flex;
    gap: 0.5rem;
    margin-bottom: 2rem;
    flex-wrap: wrap;
}

.category-btn {
    padding: 0.5rem 1rem;
    background: var(--bg-primary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    cursor: pointer;
    transition: all 0.3s ease;
}

.category-btn.active,
.category-btn:hover {
    background: var(--primary-color);
    color: white;
    border-color: var(--primary-color);
}

.faq-item {
    background: var(--bg-primary);
    margin-bottom: 1rem;
    border-radius: var(--radius-md);
    box-shadow: var(--shadow-sm);
    overflow: hidden;
}

.faq-question {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1.5rem;
    cursor: pointer;
    transition: background-color 0.3s ease;
}

.faq-question:hover {
    background: var(--bg-secondary);
}

.faq-question h3 {
    font-size: 1.125rem;
    font-weight: 600;
    color: var(--text-primary);
}

.faq-toggle {
    font-size: 1.5rem;
    font-weight: bold;
    color: var(--primary-color);
    transition: transform 0.3s ease;
}

.faq-item.active .faq-toggle {
    transform: rotate(45deg);
}

.faq-answer {
    padding: 0 1.5rem 1.5rem;
    color: var(--text-secondary);
    display: none;
}

.faq-item.active .faq-answer {
    display: block;
}

.faq-answer ul {
    margin-top: 1rem;
    padding-left: 1.5rem;
}

.faq-answer li {
    margin-bottom: 0.5rem;
}

.contact-support {
    text-align: center;
    margin-top: 3rem;
    padding: 2rem;
    background: var(--bg-primary);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-md);
}

.support-options {
    display: flex;
    gap: 1rem;
    justify-content: center;
    flex-wrap: wrap;
    margin-top: 1.5rem;
}

/* 关于我们页面样式 */
.about-main {
    padding: 2rem 0;
    background: var(--bg-secondary);
}

.about-container {
    max-width: 1000px;
    margin: 0 auto;
    padding: 0 1rem;
}

.about-title {
    text-align: center;
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: 0.5rem;
    color: var(--text-primary);
}

.about-subtitle {
    text-align: center;
    color: var(--text-secondary);
    margin-bottom: 3rem;
    font-size: 1.125rem;
}

.about-section {
    background: var(--bg-primary);
    margin-bottom: 2rem;
    padding: 2rem;
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-md);
}

.about-section h2 {
    font-size: 1.75rem;
    font-weight: 600;
    margin-bottom: 1.5rem;
    color: var(--text-primary);
}

.story-content {
    display: grid;
    grid-template-columns: 2fr 1fr;
    gap: 2rem;
    align-items: center;
}

.story-text p {
    margin-bottom: 1rem;
    color: var(--text-secondary);
}

.story-text ul {
    margin-top: 1rem;
    padding-left: 1.5rem;
}

.story-text li {
    margin-bottom: 0.5rem;
    color: var(--text-secondary);
}

.image-placeholder {
    background: var(--bg-secondary);
    border: 2px dashed var(--border-color);
    border-radius: var(--radius-md);
    padding: 3rem;
    text-align: center;
    color: var(--text-light);
}

.image-placeholder span {
    font-size: 3rem;
    display: block;
    margin-bottom: 1rem;
}

.mission-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 1rem;
}

.mission-card {
    text-align: center;
    padding: 1rem;
    background: var(--bg-secondary);
    border-radius: var(--radius-md);
    border: 1px solid var(--border-color);
}

.mission-icon {
    font-size: 2rem;
    margin-bottom: 0.75rem;
}

.mission-card h3 {
    font-size: 1.125rem;
    font-weight: 600;
    margin-bottom: 0.75rem;
    color: var(--text-primary);
}

.vision-content {
    background: var(--bg-secondary);
    padding: 1.5rem;
    border-radius: var(--radius-md);
}

.vision-content ul {
    margin-top: 1rem;
    padding-left: 1.5rem;
}

.vision-content li {
    margin-bottom: 1rem;
    color: var(--text-secondary);
}

.source-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 1rem;
    margin: 1.5rem 0;
}

.source-card {
    background: var(--bg-secondary);
    padding: 1rem;
    border-radius: var(--radius-md);
    border: 1px solid var(--border-color);
}

.source-card h4 {
    font-size: 1rem;
    font-weight: 600;
    margin-bottom: 0.75rem;
    color: var(--text-primary);
}

.algorithm-features {
    background: var(--bg-secondary);
    padding: 1.5rem;
    border-radius: var(--radius-md);
    margin-top: 1.5rem;
}

.algorithm-features ul {
    margin-top: 1rem;
    padding-left: 1.5rem;
}

.algorithm-features li {
    margin-bottom: 0.5rem;
    color: var(--text-secondary);
}

.team-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 1.5rem;
}

.team-member {
    text-align: center;
    padding: 1.5rem;
    background: var(--bg-secondary);
    border-radius: var(--radius-md);
    border: 1px solid var(--border-color);
}

.member-avatar {
    font-size: 2.5rem;
    margin-bottom: 1rem;
}

.team-member h3 {
    font-size: 1.125rem;
    font-weight: 600;
    margin-bottom: 1rem;
    color: var(--text-primary);
}

.contact-content {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 2rem;
}

.contact-item {
    display: flex;
    align-items: center;
    gap: 1rem;
    margin-bottom: 1.5rem;
}

.contact-icon {
    font-size: 1.5rem;
    width: 40px;
    height: 40px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--primary-color);
    color: white;
    border-radius: 50%;
}

.contact-item h4 {
    font-size: 1rem;
    font-weight: 600;
    margin-bottom: 0.25rem;
    color: var(--text-primary);
}

.contact-item p {
    color: var(--text-secondary);
}

.social-links {
    display: flex;
    gap: 1rem;
    flex-wrap: wrap;
}

.social-link {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.75rem 1rem;
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    text-decoration: none;
    color: var(--text-primary);
    transition: all 0.3s ease;
}

.social-link:hover {
    background: var(--primary-color);
    color: white;
    border-color: var(--primary-color);
}

.support-options {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 1.5rem;
    margin-top: 1.5rem;
}

.support-option {
    text-align: center;
    padding: 1.5rem;
    background: var(--bg-secondary);
    border-radius: var(--radius-md);
    border: 1px solid var(--border-color);
}

.support-option h3 {
    font-size: 1.125rem;
    font-weight: 600;
    margin-bottom: 1rem;
    color: var(--text-primary);
}

.support-option p {
    margin-bottom: 1.5rem;
    color: var(--text-secondary);
}

.partners-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
    gap: 1rem;
    margin-top: 1.5rem;
}

.partner-logo {
    background: var(--bg-secondary);
    padding: 1rem;
    text-align: center;
    border-radius: var(--radius-md);
    border: 1px solid var(--border-color);
    font-weight: 500;
    color: var(--text-secondary);
}

/* 页脚样式 */
.footer {
    background: var(--text-primary);
    color: white;
    padding: 3rem 0 1rem;
}

.footer-content {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 1rem;
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 2rem;
    margin-bottom: 1.5rem;
}

.footer-section h3,
.footer-section h4 {
    margin-bottom: 0.75rem;
    color: white;
}

.footer-section p {
    color: #9ca3af;
    margin-bottom: 0.75rem;
    line-height: 1.5;
}

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

.footer-section li {
    margin-bottom: 0.5rem;
    line-height: 1.4;
}

/* 功能导航部分居中对齐 */
.footer-section:nth-child(2) {
    text-align: center;
}

.footer-section:nth-child(2) ul {
    text-align: center;
}

.footer-section a {
    color: #9ca3af;
    text-decoration: none;
    transition: color 0.3s ease;
}

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

.footer-bottom {
    border-top: 1px solid #374151;
    padding-top: 1rem;
    text-align: center;
    color: #9ca3af;
}

/* 响应式设计 */
@media (max-width: 768px) {
    .hamburger {
        display: flex;
    }
    
    .nav-menu {
        position: fixed;
        left: -100%;
        top: 70px;
        flex-direction: column;
        background-color: var(--bg-primary);
        width: 100%;
        text-align: center;
        transition: 0.3s;
        box-shadow: var(--shadow-md);
        padding: 2rem 0;
    }
    
    .nav-menu.active {
        left: 0;
    }
    
    .hero-title {
        font-size: 2rem;
    }
    
    .hero-subtitle {
        font-size: 1rem;
    }
    
    .hero-buttons {
        flex-direction: column;
        align-items: center;
    }
    
    .pet-illustration {
        flex-direction: column;
        align-items: center;
    }
    
    .features-grid {
        grid-template-columns: 1fr;
    }
    
    .stats-container {
        flex-direction: column;
        text-align: center;
    }
    
    .calculator-title,
    .guide-title,
    .faq-title,
    .about-title {
        font-size: 2rem;
    }
    
    .age-comparison {
        flex-direction: column;
        text-align: center;
        gap: 1rem;
    }
    
    .age-arrow {
        transform: rotate(90deg);
    }
    
    .story-content {
        grid-template-columns: 1fr;
    }
    
    .contact-content {
        grid-template-columns: 1fr;
    }
    
    .support-options {
        grid-template-columns: 1fr;
    }
    
    .mission-grid {
        grid-template-columns: repeat(2, 1fr);
        gap: 0.75rem;
    }
    
    .mission-card {
        padding: 0.75rem;
    }
    
    .mission-icon {
        font-size: 1.5rem;
        margin-bottom: 0.5rem;
    }
    
    .mission-card h3 {
        font-size: 1rem;
        margin-bottom: 0.5rem;
    }
    
    .source-grid {
        grid-template-columns: repeat(2, 1fr);
        gap: 0.75rem;
    }
    
    .source-card {
        padding: 0.75rem;
    }
    
    .source-card h4 {
        font-size: 0.875rem;
        margin-bottom: 0.5rem;
    }
    
    .footer-content {
        grid-template-columns: 1fr;
        text-align: center;
        gap: 1.5rem;
    }
}

@media (max-width: 480px) {
    .nav-container {
        padding: 0 0.5rem;
    }
    
    .hero {
        padding: 2rem 0;
    }
    
    .hero-title {
        font-size: 1.75rem;
    }
    
    .calculator-form,
    .guide-section,
    .about-section {
        padding: 1rem;
    }
    
    .pet-type-selector {
        flex-direction: column;
    }
    
    .age-input-group {
        flex-direction: column;
    }
    
    .share-buttons {
        flex-direction: column;
    }
    
    .history-item {
        flex-direction: row;
        align-items: center;
        gap: 0.75rem;
        padding: 0.75rem;
        min-height: 60px;
    }
    
    .history-pet-info {
        display: flex;
        align-items: center;
        gap: 0.75rem;
        flex: 1;
    }
    
    .history-icon {
        font-size: 1.25rem;
        width: 35px;
        height: 35px;
        flex-shrink: 0;
    }
    
    .history-details {
        flex: 1;
        min-width: 0;
    }
    
    .history-age {
        font-size: 0.875rem;
        margin-bottom: 0.125rem;
    }
    
    .history-time {
        font-size: 0.75rem;
    }
    
    .history-redo {
        background: var(--primary-color);
        color: white;
        border: none;
        padding: 0.375rem 0.75rem;
        border-radius: var(--radius-sm);
        font-size: 0.75rem;
        font-weight: 500;
        cursor: pointer;
        transition: background-color 0.3s ease;
        flex-shrink: 0;
        white-space: nowrap;
    }
    
    .history-redo:hover {
        background: var(--primary-dark);
    }
    
    .faq-categories {
        flex-direction: column;
    }
    
    .category-btn {
        text-align: center;
    }
    
    .breed-info-grid {
        grid-template-columns: 1fr;
        gap: 0.5rem;
    }
    
    .breed-card {
        padding: 0.5rem;
    }
    
    .breed-icon {
        font-size: 1.25rem;
        margin-bottom: 0.25rem;
    }
    
    .breed-card h3 {
        font-size: 0.875rem;
        margin-bottom: 0.25rem;
    }
    
    .breed-card p {
        font-size: 0.625rem;
        margin-bottom: 0.125rem;
    }
    
    .health-tips-grid {
        grid-template-columns: 1fr;
        gap: 0.5rem;
    }
    
    /* 移动端取消特殊布局 */
    .health-tips-grid .tip-card:nth-child(4),
    .health-tips-grid .tip-card:nth-child(5) {
        grid-column: span 1;
    }
    
    .tip-card {
        padding: 0.5rem;
    }
    
    .tip-card h3 {
        font-size: 0.75rem;
        margin-bottom: 0.25rem;
    }
    
    .tip-card li {
        font-size: 0.625rem;
        padding: 0.125rem 0;
    }
    
    .mission-grid {
        grid-template-columns: 1fr;
        gap: 0.5rem;
    }
    
    .mission-card {
        padding: 0.5rem;
    }
    
    .mission-icon {
        font-size: 1.25rem;
        margin-bottom: 0.25rem;
    }
    
    .mission-card h3 {
        font-size: 0.875rem;
        margin-bottom: 0.25rem;
    }
    
    .source-grid {
        grid-template-columns: 1fr;
        gap: 0.5rem;
    }
    
    .source-card {
        padding: 0.5rem;
    }
    
    .source-card h4 {
        font-size: 0.75rem;
        margin-bottom: 0.25rem;
    }
}

/* 计算步骤样式 */
.steps {
    padding: 4rem 0;
    background: var(--bg-primary);
}

.steps-container {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 2rem;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 1rem;
}

.step-card {
    background: var(--bg-secondary);
    padding: 2rem;
    border-radius: var(--radius-lg);
    text-align: center;
    box-shadow: var(--shadow-md);
    transition: transform 0.3s ease;
    position: relative;
}

.step-card:hover {
    transform: translateY(-5px);
}

.step-number {
    position: absolute;
    top: -15px;
    left: 50%;
    transform: translateX(-50%);
    background: var(--primary-color);
    color: white;
    width: 30px;
    height: 30px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 700;
    font-size: 1.125rem;
}

.step-icon {
    font-size: 3rem;
    margin-bottom: 1rem;
}

.step-card h3 {
    font-size: 1.25rem;
    font-weight: 600;
    margin-bottom: 1rem;
    color: var(--text-primary);
}

/* 解决的问题样式 */
.problems {
    padding: 4rem 0;
    background: var(--bg-primary);
}

.problems-grid {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 1rem;
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 2rem;
}

.problem-card {
    background: var(--bg-secondary);
    padding: 2rem;
    border-radius: var(--radius-lg);
    border-left: 4px solid var(--primary-color);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.problem-card:hover {
    transform: translateY(-3px);
    box-shadow: var(--shadow-lg);
}

.problem-icon {
    font-size: 2.5rem;
    margin-bottom: 1rem;
}

.problem-card h3 {
    font-size: 1.25rem;
    font-weight: 600;
    margin-bottom: 0.75rem;
    color: var(--text-primary);
}

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

/* 用户反馈样式 */
.testimonials {
    padding: 4rem 0;
    background: var(--bg-primary);
}

.testimonials-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 2rem;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 1rem;
}

.testimonial-card {
    background: var(--bg-secondary);
    padding: 2rem;
    border-radius: var(--radius-lg);
    text-align: center;
    box-shadow: var(--shadow-md);
    transition: transform 0.3s ease;
}

.testimonial-card:hover {
    transform: translateY(-5px);
}

.testimonial-avatar {
    font-size: 3rem;
    margin-bottom: 1rem;
}

.testimonial-content p {
    font-size: 1rem;
    line-height: 1.6;
    color: var(--text-secondary);
    margin-bottom: 1rem;
    font-style: italic;
}

.testimonial-author {
    margin-bottom: 0.5rem;
}

.testimonial-author strong {
    color: var(--text-primary);
    font-weight: 600;
    display: block;
    margin-bottom: 0.25rem;
}

.testimonial-author span {
    color: var(--text-secondary);
    font-size: 0.875rem;
}

.testimonial-rating {
    color: var(--accent-color);
    font-size: 1rem;
}

/* 响应式设计补充 */
@media (max-width: 768px) {
    .steps-container,
    .testimonials-grid {
        grid-template-columns: 1fr;
        gap: 1.5rem;
    }
    
    .step-card,
    .testimonial-card {
        padding: 1.5rem;
    }
    
    .step-icon,
    .testimonial-avatar {
        font-size: 2rem;
    }
    
    .breed-info-grid {
        grid-template-columns: repeat(2, 1fr);
        gap: 0.75rem;
    }
    
    .breed-card {
        padding: 0.75rem;
    }
    
    .breed-icon {
        font-size: 1.5rem;
        margin-bottom: 0.5rem;
    }
    
    .breed-card h3 {
        font-size: 1rem;
        margin-bottom: 0.5rem;
    }
    
    .breed-card p {
        font-size: 0.75rem;
        margin-bottom: 0.125rem;
    }
    
    .health-tips-grid {
        grid-template-columns: repeat(2, 1fr);
        gap: 0.75rem;
    }
    
    /* 平板端取消特殊布局 */
    .health-tips-grid .tip-card:nth-child(4),
    .health-tips-grid .tip-card:nth-child(5) {
        grid-column: span 1;
    }
    
    .tip-card {
        padding: 0.75rem;
    }
    
    .tip-card h3 {
        font-size: 0.875rem;
        margin-bottom: 0.5rem;
    }
    
    .tip-card li {
        font-size: 0.75rem;
        padding: 0.125rem 0;
    }
}

/* 移动端响应式 */
@media (max-width: 768px) {
    .language-switcher {
        gap: 0.25rem;
    }
    
    .lang-btn {
        padding: 0.375rem 0.75rem;
        font-size: 0.75rem;
    }
    
    .nav-container {
        padding: 0 1rem;
    }
    
    .nav-menu {
        position: fixed;
        left: -100%;
        top: 70px;
        flex-direction: column;
        background-color: var(--bg-primary);
        width: 100%;
        text-align: center;
        transition: 0.3s;
        box-shadow: 0 10px 27px rgba(0, 0, 0, 0.05);
        padding: 2rem 0;
    }
    
    .nav-menu.active {
        left: 0;
    }
    
    .nav-menu li {
        margin: 1rem 0;
    }
    
    .hamburger {
        display: flex;
    }
    
    .hamburger.active .bar:nth-child(2) {
        opacity: 0;
    }
    
    .hamburger.active .bar:nth-child(1) {
        transform: translateY(8px) rotate(45deg);
    }
    
    .hamburger.active .bar:nth-child(3) {
        transform: translateY(-8px) rotate(-45deg);
    }
}