:root {
    /* Aviation-themed color palette */
    --sky-blue: #4A90E2;
    --cloud-white: #F8FAFE;
    --horizon-blue: #6BB6FF;
    --aircraft-silver: #C0C8D1;
    --sunset-orange: #FF8C42;
    --deep-blue: #2C5282;
    --font-serif: 'Georgia', 'Times New Roman', serif;
    --font-sans-serif: 'Helvetica Neue', 'Arial', sans-serif;
    --header-height: 70px;
}

body {
    color: #333;
    font-family: var(--font-sans-serif);
    margin: 0;
    padding: 0;
    overflow-x: hidden;
    /* Enhanced aviation-themed sky background with smooth transitions */
    background: 
        /* Multi-layer sky gradient for smooth transitions */
        linear-gradient(180deg, 
            rgba(248, 250, 254, 0.95) 0%,    /* Light cloud white (matches header) */
            rgba(176, 224, 230, 0.8) 15%,    /* Powder blue */
            rgba(135, 206, 235, 0.7) 35%,    /* Sky blue */
            rgba(224, 246, 255, 0.8) 55%,    /* Light blue */
            rgba(255, 248, 220, 0.9) 75%,    /* Cornsilk (horizon) */
            rgba(74, 144, 226, 0.3) 85%,     /* Transition to footer */
            rgba(44, 82, 130, 0.6) 100%      /* Deep blue (matches footer) */
        );
    background-size: 100% 100%;
    background-repeat: no-repeat;
    padding-top: var(--header-height);
}

.search-container {
    padding: 2rem;
    max-width: 1600px;
    margin: 0 auto;
}

/* Aviation-themed paper sheets with cloud-like edges */
.paper-sheet {
    background: linear-gradient(135deg, var(--cloud-white) 0%, #ffffff 100%);
    padding: 2rem;
    margin-bottom: 2rem;
    position: relative;
    box-shadow: 0 10px 30px rgba(74, 144, 226, 0.15);
    border-radius: 12px;
    border: 1px solid rgba(74, 144, 226, 0.1);
    transition: all 0.3s ease-in-out;
}

/* Cloud-like decorative elements */
.paper-sheet::before {
    content: '🔍';
    position: absolute;
    top: -8px;
    right: 20px;
    font-size: 1.2rem;
    opacity: 0.6;
    animation: search-pulse 3s ease-in-out infinite;
}

@keyframes search-pulse {
    0%, 100% { transform: scale(1); opacity: 0.6; }
    50% { transform: scale(1.1); opacity: 0.8; }
}

.paper-sheet:hover {
    transform: translateY(-5px);
    box-shadow: 0 20px 40px rgba(74, 144, 226, 0.2);
    border-color: var(--sky-blue);
}

/* 搜索表单样式 */
.search-form-container {
    text-align: center;
    margin-bottom: 2rem;
}

.search-title {
    font-family: var(--font-serif);
    font-size: 2.5rem;
    font-weight: bold;
    margin: 0 0 1rem 0;
    color: var(--deep-blue);
    text-shadow: 0 0 1px rgba(0,0,0,0.1);
}

.search-subtitle {
    color: rgba(44, 82, 130, 0.8);
    font-size: 1.1rem;
    margin-bottom: 2rem;
}

.search-form {
    display: grid;
    grid-template-columns: 200px 400px auto;
    gap: 15px;
    align-items: center;
    margin-bottom: 1rem;
    justify-content: center;
}

.form-select, .form-control {
    padding: 12px 15px;
    border: 2px solid rgba(74, 144, 226, 0.2);
    border-radius: 25px;
    font-size: 1rem;
    background: white;
    transition: all 0.3s ease;
    -webkit-appearance: none;
    appearance: none;
}

.form-select {
    background-image: url('data:image/svg+xml,<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 16 16"><path fill="none" stroke="%23343a40" stroke-linecap="round" stroke-linejoin="round" stroke-width="2" d="M2 5l6 6 6-6"/></svg>');
    background-repeat: no-repeat;
    background-position: right 0.75rem center;
    background-size: 16px 12px;
}

.form-select:focus, .form-control:focus {
    border-color: var(--sky-blue);
    box-shadow: 0 0 0 3px rgba(74, 144, 226, 0.1);
    outline: none;
}

.search-btn {
    background: linear-gradient(135deg, var(--sky-blue), var(--horizon-blue));
    color: white;
    border: none;
    padding: 12px 25px;
    border-radius: 25px;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
    display: flex;
    align-items: center;
    gap: 8px;
    box-shadow: 0 4px 15px rgba(74, 144, 226, 0.3);
}

.search-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(74, 144, 226, 0.4);
}

.search-description {
    color: rgba(44, 82, 130, 0.7);
    font-size: 0.9rem;
    margin-top: 1rem;
    text-align: center;
}

/* 搜索结果样式 */
.results-header {
    text-align: center;
    margin-bottom: 2rem;
}

.results-title {
    font-family: var(--font-serif);
    font-size: 2rem;
    font-weight: bold;
    color: var(--deep-blue);
    margin-bottom: 1rem;
}

.results-stats {
    color: rgba(44, 82, 130, 0.8);
    font-size: 1rem;
}

/* 图片网格样式 */
.gallery-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 2rem;
    margin-bottom: 2rem;
}

.gallery-card {
    background: linear-gradient(135deg, var(--cloud-white) 0%, #ffffff 100%);
    border-radius: 15px;
    overflow: hidden;
    position: relative;
    box-shadow: 0 8px 25px rgba(74, 144, 226, 0.15);
    border: 1px solid rgba(74, 144, 226, 0.1);
    transition: all 0.3s ease;
}

.gallery-card:hover {
    transform: translateY(-8px);
    box-shadow: 0 15px 35px rgba(74, 144, 226, 0.25);
    border-color: var(--sky-blue);
}

.card-image-container {
    position: relative;
    overflow: hidden;
    height: 200px;
}

.gallery-image {
    width: 100%;
    height: 100%;
    object-fit: cover;
    transition: transform 0.3s ease;
}

.gallery-card:hover .gallery-image {
    transform: scale(1.05);
}

.image-id-badge {
    position: absolute;
    top: 10px;
    right: 10px;
    background: linear-gradient(135deg, var(--sky-blue), var(--horizon-blue));
    color: white;
    padding: 6px 12px;
    border-radius: 15px;
    font-size: 0.8rem;
    font-weight: 600;
    z-index: 10;
    box-shadow: 0 3px 8px rgba(0, 0, 0, 0.3);
    transition: all 0.3s ease;
}

.gallery-card:hover .image-id-badge {
    transform: scale(1.1);
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.4);
}

.card-content {
    padding: 1.5rem;
}

.card-title {
    font-size: 1.1rem;
    font-weight: 600;
    color: var(--deep-blue);
    margin-bottom: 0.8rem;
    line-height: 1.3;
    display: -webkit-box;
    -webkit-line-clamp: 2;
    -webkit-box-orient: vertical;
    overflow: hidden;
}

.card-meta {
    display: flex;
    align-items: center;
    gap: 8px;
    margin-bottom: 1rem;
    color: rgba(44, 82, 130, 0.7);
    font-size: 0.9rem;
}

.photographer-link {
    color: var(--sky-blue);
    text-decoration: none;
    font-weight: 500;
    transition: color 0.2s ease;
}

.photographer-link:hover {
    color: var(--horizon-blue);
    text-decoration: underline;
}

.card-stats {
    display: flex;
    justify-content: space-between;
    align-items: center;
    font-size: 0.85rem;
    color: rgba(44, 82, 130, 0.6);
    margin-top: 0.5rem;
    flex-wrap: nowrap;
    gap: 10px;
}

.date {
    flex: 0 0 auto;
    text-align: left;
    line-height: 1.2;
    white-space: nowrap;
    min-width: 0;
}

.stats-group {
    display: flex;
    gap: 12px;
    flex-shrink: 0;
    align-items: center;
}

.stat-item {
    display: flex;
    align-items: center;
    gap: 4px;
    white-space: nowrap;
}

/* 加载指示器 */
.loading-indicator {
    display: none;
    text-align: center;
    padding: 2rem;
}

.loading-spinner {
    width: 40px;
    height: 40px;
    border: 4px solid rgba(74, 144, 226, 0.1);
    border-left: 4px solid var(--sky-blue);
    border-radius: 50%;
    animation: spin 1s linear infinite;
    margin: 0 auto 1rem;
}

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

/* 无结果状态 */
.no-results {
    text-align: center;
    padding: 3rem;
    color: rgba(44, 82, 130, 0.7);
}

.no-results-icon {
    font-size: 4rem;
    color: rgba(74, 144, 226, 0.3);
    margin-bottom: 1rem;
}

.no-results h3 {
    font-size: 1.5rem;
    color: var(--deep-blue);
    margin-bottom: 0.5rem;
}

/* 响应式设计 */
@media (max-width: 1200px) {
    .gallery-grid {
        grid-template-columns: repeat(3, 1fr);
    }
}

@media (max-width: 900px) {
    .gallery-grid {
        grid-template-columns: repeat(2, 1fr);
    }
}

@media (max-width: 768px) {
    .search-container {
        padding: 1rem;
    }

    .search-form {
        grid-template-columns: 1fr;
        gap: 10px;
        justify-content: stretch;
    }

    .form-select, .form-control {
        width: 100%;
        box-sizing: border-box;
    }

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

    .gallery-grid {
        grid-template-columns: repeat(2, 1fr);
        gap: 1.5rem;
    }

    .paper-sheet {
        padding: 1.5rem;
    }

    .card-image-container {
        height: 180px;
    }

    .stats-group {
        gap: 8px;
    }

    .card-stats {
        gap: 8px;
    }
}

@media (max-width: 1024px) and (min-width: 769px) {
    .search-form {
        grid-template-columns: 180px 350px auto;
        justify-content: center;
    }
}

@media (max-width: 480px) {
    .gallery-grid {
        grid-template-columns: 1fr;
    }

    .search-title {
        font-size: 1.8rem;
    }

    .stats-group {
        gap: 6px;
    }

    .card-stats {
        gap: 6px;
        font-size: 0.8rem;
    }

    .stat-item {
        font-size: 0.8rem;
        gap: 3px;
    }
}