/* === Material Design 配色系统 === */
:root {
  /* Primary colors */
  --md-primary-50: #e3f2fd;
  --md-primary-100: #bbdefb;
  --md-primary-200: #90caf9;
  --md-primary-300: #64b5f6;
  --md-primary-400: #42a5f5;
  --md-primary-500: #2196f3;
  --md-primary-600: #1e88e5;
  --md-primary-700: #1976d2;
  --md-primary-800: #1565c0;
  --md-primary-900: #0d47a1;
  
  /* Secondary colors */
  --md-secondary-50: #fce4ec;
  --md-secondary-100: #f8bbd9;
  --md-secondary-200: #f48fb1;
  --md-secondary-300: #f06292;
  --md-secondary-400: #ec407a;
  --md-secondary-500: #e91e63;
  --md-secondary-600: #d81b60;
  --md-secondary-700: #c2185b;
  --md-secondary-800: #ad1457;
  --md-secondary-900: #880e4f;
  
  /* Background colors */
  --md-surface: #ffffff;
  --md-background: #fafafa;
  --md-card: #ffffff;
  
  /* Text colors */
  --md-text-primary: rgba(0, 0, 0, 0.87);
  --md-text-secondary: rgba(0, 0, 0, 0.6);
  --md-text-hint: rgba(0, 0, 0, 0.38);
  
  /* Divider colors */
  --md-divider: rgba(0, 0, 0, 0.12);
  
  /* Status colors */
  --md-success: #4caf50;
  --md-warning: #ff9800;
  --md-error: #f44336;
  --md-info: #2196f3;
  
  /* Material Design elevation shadows */
  --md-shadow-1: 0px 2px 1px -1px rgba(0,0,0,0.2),0px 1px 1px 0px rgba(0,0,0,0.14),0px 1px 3px 0px rgba(0,0,0,0.12);
  --md-shadow-2: 0px 3px 1px -2px rgba(0,0,0,0.2),0px 2px 2px 0px rgba(0,0,0,0.14),0px 1px 5px 0px rgba(0,0,0,0.12);
  --md-shadow-3: 0px 3px 3px -2px rgba(0,0,0,0.2),0px 3px 4px 0px rgba(0,0,0,0.14),0px 1px 8px 0px rgba(0,0,0,0.12);
  --md-shadow-4: 0px 2px 4px -1px rgba(0,0,0,0.2),0px 4px 5px 0px rgba(0,0,0,0.14),0px 1px 10px 0px rgba(0,0,0,0.12);
  --md-shadow-5: 0px 8px 10px -5px rgba(0,0,0,0.2),0px 16px 24px 2px rgba(0,0,0,0.14),0px 6px 30px 5px rgba(0,0,0,0.12);
  
  /* Material Design typography */
  --md-font-family: 'Roboto', 'Segoe UI', 'Helvetica Neue', sans-serif;
  --md-font-size-xs: 0.75rem;
  --md-font-size-sm: 0.875rem;
  --md-font-size-base: 1rem;
  --md-font-size-lg: 1.125rem;
  --md-font-size-xl: 1.25rem;
  --md-font-size-2xl: 1.5rem;
  --md-font-size-3xl: 2rem;
}

/* === Material Design 基础样式 === */

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

body {
    font-family: var(--md-font-family);
    line-height: 1.6;
    color: var(--md-text-primary);
    background-color: var(--md-background);
    color-scheme: light;
}

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

/* === Material Design 头部 === */

header {
    background-color: var(--md-primary-700);
    color: white;
    padding: 2.5rem 0 1.5rem;
    text-align: center;
    box-shadow: var(--md-shadow-4);
    position: relative;
    overflow: hidden;
}

header::before {
    content: '';
    position: absolute;
    top: -50%;
    left: -50%;
    width: 200%;
    height: 200%;
    background: radial-gradient(circle, rgba(255,255,255,0.1) 0%, transparent 70%);
    transform: rotate(30deg);
}

header h1 {
    font-size: var(--md-font-size-3xl);
    margin-bottom: 0.5rem;
    font-weight: 500;
    position: relative;
    z-index: 1;
}

.subtitle {
    font-size: var(--md-font-size-lg);
    opacity: 0.9;
    margin-bottom: 1rem;
    position: relative;
    z-index: 1;
}

/* === Material Design 推荐模块 === */

#ai-recommender {
    background: var(--md-surface);
    padding: 2.5rem 0;
    margin-bottom: 2rem;
    border-radius: 16px;
    box-shadow: var(--md-shadow-3);
    margin-top: -1.5rem;
    position: relative;
    z-index: 1;
    overflow: hidden;
}

#ai-recommender::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 4px;
    background: linear-gradient(90deg, var(--md-primary-500), var(--md-secondary-500));
}

#ai-recommender h2 {
    text-align: center;
    margin-bottom: 2rem;
    font-size: var(--md-font-size-2xl);
    color: var(--md-text-primary);
    font-weight: 500;
    position: relative;
}

.recommend-options {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 1.5rem;
    margin-bottom: 1.5rem;
    padding: 1.5rem;
    background: var(--md-background);
    border-radius: 12px;
    margin: 0 1rem;
}

.recommend-btn {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    padding: 1rem;
    background: var(--md-surface);
    border: none;
    border-radius: 12px;
    color: var(--md-text-primary);
    font-size: var(--md-font-size-base);
    font-weight: 500;
    cursor: pointer;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    box-shadow: var(--md-shadow-1);
    position: relative;
    overflow: hidden;
    min-height: 80px;
    text-align: center;
}

.recommend-btn:hover {
    transform: translateY(-2px);
    box-shadow: var(--md-shadow-3);
    color: var(--md-text-primary);
}

.recommend-btn:active {
    transform: translateY(0);
    box-shadow: var(--md-shadow-2);
}

.recommend-btn::after {
    content: '';
    position: absolute;
    top: 50%;
    left: 50%;
    width: 0;
    height: 0;
    background: rgba(255, 255, 255, 0.3);
    border-radius: 50%;
    transform: translate(-50%, -50%);
    transition: width 0.6s, height 0.6s;
}

.recommend-btn:active::after {
    width: 300px;
    height: 300px;
}

.recommend-btn.sweet {
    background: linear-gradient(135deg, var(--md-secondary-100), var(--md-secondary-300));
    color: var(--md-text-primary);
}

.recommend-btn.fresh {
    background: linear-gradient(135deg, #e8f5e9, #c8e6c9);
    color: var(--md-text-primary);
}

.recommend-btn.quick {
    background: linear-gradient(135deg, #fff8e1, #ffecb3);
    color: var(--md-text-primary);
}

.recommend-btn.random {
    background: linear-gradient(135deg, #f3e5f5, #e1bee7);
    color: var(--md-text-primary);
}

.recommend-btn.time-based {
    background: linear-gradient(135deg, #e3f2fd, #bbdefb);
    color: var(--md-text-primary);
}

.emoji {
    font-size: var(--md-font-size-xl);
    line-height: 1;
}

#recommend-result-container {
    text-align: center;
    margin-top: 1rem;
    padding: 0 1rem;
}

.loading {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 1rem;
    color: var(--md-text-secondary);
}

.spinner {
    width: 20px;
    height: 20px;
    border: 3px solid var(--md-divider);
    border-top: 3px solid var(--md-primary-500);
    border-radius: 50%;
    animation: spin 1s linear infinite;
}

@keyframes spin {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
}

.recommendation {
    font-size: var(--md-font-size-lg);
    color: var(--md-text-primary);
    min-height: 60px;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 0.5rem;
}

.recommendation a {
    color: var(--md-primary-700);
    text-decoration: none;
    font-weight: 500;
    transition: color 0.3s ease;
}

.recommendation a:hover {
    color: var(--md-primary-900);
    text-decoration: underline;
}

.recommendation.empty {
    color: var(--md-text-hint);
    font-style: italic;
}

.error {
    color: var(--md-error);
    background: #ffebee;
    border: 1px solid var(--md-error);
    padding: 1rem;
    border-radius: 8px;
    display: none; /* 默认隐藏 */
    margin: 0 1rem;
}

/* === Material Design 菜谱搜索模块 === */

#recipe-search {
    padding: 2rem 0;
}

#recipe-search h2 {
    text-align: center;
    margin-bottom: 2rem;
    color: var(--md-text-primary);
    font-size: var(--md-font-size-2xl);
    font-weight: 500;
}

.search-controls {
    display: flex;
    align-items: center;
    gap: 1rem;
    margin-bottom: 2rem;
    position: relative;
    background: var(--md-surface);
    padding: 1rem;
    border-radius: 12px;
    box-shadow: var(--md-shadow-1);
}

#search-box {
    flex: 1;
    padding: 1rem 1.5rem;
    border: none;
    border-radius: 8px;
    font-size: var(--md-font-size-base);
    transition: all 0.3s ease;
    background: var(--md-background);
    border: 1px solid var(--md-divider);
}

#search-box:focus {
    outline: none;
    border-color: var(--md-primary-500);
    box-shadow: 0 0 0 2px rgba(33, 150, 243, 0.2);
}

#clear-search {
    background: var(--md-error);
    color: white;
    border: none;
    border-radius: 50%;
    width: 36px;
    height: 36px;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    font-size: 1.2rem;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

#clear-search:hover {
    background: #d32f2f;
    transform: scale(1.1);
    box-shadow: var(--md-shadow-2);
}

.filter-controls {
    display: flex;
    gap: 2rem;
    margin-bottom: 2rem;
    align-items: center;
    background: var(--md-surface);
    padding: 1rem;
    border-radius: 12px;
    box-shadow: var(--md-shadow-1);
}

.filter-group {
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.filter-label {
    font-weight: 500;
    color: var(--md-text-primary);
    font-size: var(--md-font-size-sm);
}

.filter-select {
    padding: 0.75rem 1rem;
    border: 1px solid var(--md-divider);
    border-radius: 8px;
    font-size: var(--md-font-size-base);
    background: var(--md-surface);
    cursor: pointer;
    transition: border-color 0.3s ease;
    min-width: 120px;
}

.filter-select:focus {
    outline: none;
    border-color: var(--md-primary-500);
    box-shadow: 0 0 0 2px rgba(33, 150, 243, 0.2);
}

/* === Material Design 菜谱网格 === */

.recipe-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
    gap: 1.5rem;
    margin-top: 2rem;
}

.recipe-card {
    background: var(--md-surface);
    border-radius: 16px;
    overflow: hidden;
    box-shadow: var(--md-shadow-2);
    transition: transform 0.3s cubic-bezier(0.4, 0, 0.2, 1), box-shadow 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    cursor: pointer;
    border: none;
}

.recipe-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--md-shadow-4);
}

.recipe-card:focus {
    outline: none;
    box-shadow: 0 0 0 2px var(--md-primary-500);
}

.recipe-card img {
    width: 100%;
    height: 180px;
    object-fit: cover;
    transition: transform 0.3s ease;
}

.recipe-card:hover img {
    transform: scale(1.05);
}

.recipe-card-content {
    padding: 1.5rem;
}

.recipe-card h3 {
    font-size: var(--md-font-size-lg);
    font-weight: 500;
    color: var(--md-text-primary);
    margin-bottom: 0.5rem;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

/* === Material Design 模态框 === */

.modal {
    display: none;
    position: fixed;
    z-index: 1000;
    left: 0;
    top: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0,0,0,0.5);
    backdrop-filter: blur(5px);
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 1rem;
}

.modal-content {
    background: var(--md-surface);
    border-radius: 16px;
    overflow: hidden;
    max-width: 600px;
    max-height: 90vh;
    display: flex;
    flex-direction: column;
    box-shadow: var(--md-shadow-5);
    width: 100%;
    max-width: 90vw;
}

.modal-header {
    padding: 1.5rem;
    border-bottom: 1px solid var(--md-divider);
    background: var(--md-primary-600);
    color: white;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.modal-header h2 {
    font-size: var(--md-font-size-xl);
    margin: 0;
    font-weight: 500;
}

.close-btn {
    background: none;
    border: none;
    color: white;
    font-size: var(--md-font-size-xl);
    cursor: pointer;
    width: 40px;
    height: 40px;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: 50%;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

.close-btn:hover {
    background: rgba(255,255,255,0.2);
    transform: scale(1.1);
}

.modal-body {
    flex: 1;
    overflow-y: auto;
    padding: 1.5rem;
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
}

.recipe-image-container {
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--md-background);
    border-radius: 8px;
    overflow: hidden;
    height: 200px;
}

.recipe-image-container img {
    max-width: 100%;
    max-height: 180px;
    object-fit: contain;
    border-radius: 4px;
}

.recipe-details {
    flex: 1;
}

.section {
    margin-bottom: 1.5rem;
}

.section h3 {
    font-size: var(--md-font-size-lg);
    font-weight: 500;
    color: var(--md-text-primary);
    margin-bottom: 1rem;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.section-icon {
    font-size: var(--md-font-size-lg);
}

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

.section ul, .section ol {
    margin-bottom: 0.5rem;
}

.section li, .section ol li {
    padding: 0.5rem 0;
    border-left: 3px solid var(--md-divider);
    padding-left: 0.75rem;
    margin-bottom: 0.25rem;
    font-size: var(--md-font-size-base);
    line-height: 1.5;
    transition: background-color 0.3s ease;
}

.modal-footer {
    padding: 1rem;
    border-top: 1px solid var(--md-divider);
    background: var(--md-background);
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.recipe-ingredients li:hover, .recipe-steps ol li:hover {
    background-color: var(--md-background);
    border-left-color: var(--md-primary-500);
}

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

.difficulty-tag {
    background: var(--md-error);
    padding: 0.25rem 0.75rem;
    border-radius: 12px;
    font-weight: 500;
    font-size: var(--md-font-size-sm);
    color: white;
    display: inline-block;
}

.category-tag {
    background: var(--md-primary-500);
    padding: 0.25rem 0.75rem;
    border-radius: 12px;
    font-weight: 500;
    font-size: var(--md-font-size-sm);
    color: white;
    display: inline-block;
}

/* === Material Design 响应式设计 === */

@media (max-width: 768px) {
    .container {
        padding: 0 15px;
    }
    
    header h1 {
        font-size: var(--md-font-size-2xl);
    }
    
    #ai-recommender h2 {
        font-size: var(--md-font-size-xl);
    }
    
    .recommend-options {
        grid-template-columns: repeat(2, 1fr);
        padding: 1rem;
        margin: 0 0.5rem;
    }
    
    .recipe-grid {
        grid-template-columns: 1fr;
        gap: 1rem;
    }
    
    .modal-body {
        padding: 1rem;
        flex-direction: column;
        gap: 1rem;
    }
    
    .recipe-image-container {
        width: 100%;
        height: 150px;
    }
    
    .filter-controls {
        flex-direction: column;
        align-items: stretch;
        gap: 1rem;
    }
    
    .filter-group {
        flex-direction: column;
        align-items: flex-start;
        gap: 0.5rem;
    }
}

/* === 工具类 === */

.clearfix::after {
    content: "";
    display: table;
    clear: both;
}

.hidden {
    display: none !important;
}

.visible {
    display: block !important;
}

/* === 动画 === */

.fade-in {
    animation: fadeIn 0.3s ease-in;
}

@keyframes fadeIn {
    from { opacity: 0; }
    to { opacity: 1; }
}

.slide-up {
    animation: slideUp 0.3s ease-out;
}

@keyframes slideUp {
    from {
        transform: translateY(20px);
        opacity: 0;
    }
    to {
        transform: translateY(0);
        opacity: 1;
    }
}

/* === 页面布局优化 === */

body {
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

main {
    flex: 1;
}

/* === 滚动条样式 === */

::-webkit-scrollbar {
    width: 8px;
    height: 8px;
}

::-webkit-scrollbar-track {
    background: #f1f1f1;
    border-radius: 4px;
}

::-webkit-scrollbar-thumb {
    background: #c1c1c1;
    border-radius: 4px;
}

::-webkit-scrollbar-thumb:hover {
    background: #a8a8a8;
}

/* === 访问性 === */

@media (prefers-reduced-motion: reduce) {
    *, *::before, *::after {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
    }
}

.js-enabled #recipe-grid {
    opacity: 1;
}

.no-js #recipe-grid {
    opacity: 0.5;
}

/* === 错误状态 === */

.error-state {
    border: 2px solid #e74c3c;
    background: #fdf2f2;
    padding: 1rem;
    border-radius: 8px;
    margin: 0.5rem 0;
}

/* === 加载状态 === */

.loading-state {
    opacity: 0.6;
}

/* === 标签云样式 === */

.tag-cloud {
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
    margin: 1rem 0;
}

.tag {
    background: #e8f4fd;
    padding: 0.25rem 0.75rem;
    border-radius: 12px;
    font-size: 0.8rem;
    font-weight: 500;
    color: #2c3e50;
    border: 1px solid #d1e8ff;
}

.tag:hover {
    background: #d1e8ff;
    color: #2c3e50;
    transform: translateY(-1px);
}

/* === 暗色主题支持 === */

@media (prefers-color-scheme: dark) {
    body {
        background-color: #1a1a1a;
        color: #e0e0e0;
    }
    
    .container {
        background: #2a2a2a;
        border-radius: 12px;
        margin-top: 2rem;
    }
    
    .recipe-card {
        background: #333;
        border-color: #555;
    }
    
    .recipe-card:hover {
        background: #444;
        border-color: #666;
    }
    
    .recipe-card h3 {
        color: #e0e0e0;
    }
    
    .button {
        background: #555;
        color: #fff;
    }
    
    .button:hover {
        background: #666;
    }
}