:root {
    --primary-color: #4a6fa5;
    --secondary-color: #6c757d;
    --success-color: #28a745;
    --danger-color: #dc3545;
    --light-color: #f8f9fa;
    --dark-color: #343a40;
    --border-radius: 8px;
    --box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
    --transition: all 0.3s ease;
}

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

html {
    scroll-behavior: smooth;
    font-size: 16px;
}

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    line-height: 1.6;
    color: #333;
    background-color: #f5f7fa;
    padding: 0;
    margin: 0;
}

.visually-hidden {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    white-space: nowrap;
    border: 0;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 2rem 1rem;
}

header {
    text-align: center;
    margin-bottom: 2rem;
}

h1 {
    font-size: 2.5rem;
    color: var(--primary-color);
    margin-bottom: 0.5rem;
}

h2 {
    font-size: 1.8rem;
    color: var(--primary-color);
    margin-bottom: 1rem;
}

.language-switcher {
    display: flex;
    justify-content: center;
    gap: 0.5rem;
    margin-top: 1rem;
}

.language-switcher button {
    padding: 0.5rem 1rem;
    background-color: var(--light-color);
    border: 1px solid var(--secondary-color);
    border-radius: var(--border-radius);
    cursor: pointer;
    transition: var(--transition);
}

.language-switcher button[aria-pressed="true"] {
    background-color: var(--primary-color);
    color: white;
    border-color: var(--primary-color);
}

.gallery-section {
    background-color: white;
    padding: 2rem;
    border-radius: var(--border-radius);
    box-shadow: var(--box-shadow);
    margin-bottom: 2rem;
}

.image-gallery {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
    gap: 1rem;
    margin-top: 1rem;
}

.image-item {
    position: relative;
    border-radius: var(--border-radius);
    overflow: hidden;
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
    transition: var(--transition);
    aspect-ratio: 1/1;
}

.image-item:hover {
    transform: translateY(-5px);
    box-shadow: 0 6px 12px rgba(0, 0, 0, 0.15);
}

.image-item img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    display: block;
}

.remove-btn {
    position: absolute;
    top: 0.5rem;
    right: 0.5rem;
    background-color: var(--danger-color);
    color: white;
    border: none;
    width: 24px;
    height: 24px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    opacity: 0;
    transition: var(--transition);
}

.image-item:hover .remove-btn {
    opacity: 1;
}

.compact-upload-area {
    margin-top: 1rem;
}

.upload-container {
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.upload-area {
    border: 2px dashed var(--secondary-color);
    border-radius: var(--border-radius);
    padding: 0.75rem 1rem;
    text-align: center;
    cursor: pointer;
    transition: var(--transition);
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    min-width: 120px;
}

.upload-area:hover {
    border-color: var(--primary-color);
    background-color: rgba(74, 111, 165, 0.05);
}

.upload-area svg {
    margin: 0;
    width: 18px;
    height: 18px;
}

#uploadText {
    font-size: 0.9rem;
    white-space: nowrap;
}

.small-btn {
    padding: 0.5rem 0.75rem;
    font-size: 0.85rem;
}

.random-section {
    background-color: white;
    padding: 2rem;
    border-radius: var(--border-radius);
    box-shadow: var(--box-shadow);
    text-align: center;
}

.random-controls {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    align-items: center;
    gap: 1rem;
    margin-top: 1.5rem;
}

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

.input-group label {
    font-weight: 500;
}

.input-group input {
    padding: 0.5rem;
    border: 1px solid #ddd;
    border-radius: var(--border-radius);
    width: 60px;
    text-align: center;
}

.toggle-group {
    display: flex;
    align-items: center;
}

.toggle-label {
    position: relative;
    display: inline-flex;
    align-items: center;
    cursor: pointer;
    gap: 0.5rem;
}

.toggle-label input {
    opacity: 0;
    width: 0;
    height: 0;
}

.toggle-slider {
    position: relative;
    width: 50px;
    height: 24px;
    background-color: #ccc;
    border-radius: 24px;
    transition: .4s;
}

.toggle-slider:before {
    content: "";
    position: absolute;
    height: 16px;
    width: 16px;
    left: 4px;
    bottom: 4px;
    background-color: white;
    border-radius: 50%;
    transition: .4s;
}

.toggle-label input:checked + .toggle-slider {
    background-color: var(--primary-color);
}

.toggle-label input:checked + .toggle-slider:before {
    transform: translateX(26px);
}

#skipAnimationText {
    font-size: 0.9rem;
    white-space: nowrap;
}

button {
    padding: 0.75rem 1.5rem;
    border: none;
    border-radius: var(--border-radius);
    font-weight: 500;
    cursor: pointer;
    transition: var(--transition);
}

button:disabled {
    opacity: 0.6;
    cursor: not-allowed;
}

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

.primary-btn:hover:not(:disabled) {
    background-color: #3a5a8f;
    transform: translateY(-2px);
}

.secondary-btn {
    background-color: var(--light-color);
    color: var(--dark-color);
    border: 1px solid #ddd;
}

.secondary-btn:hover:not(:disabled) {
    background-color: #e9ecef;
}

footer {
    text-align: center;
    margin-top: 3rem;
    color: var(--secondary-color);
    font-size: 0.9rem;
}

/* 动画效果 */
@keyframes selectedPulse {
    0% { 
        transform: scale(1);
        box-shadow: 0 0 0 0 rgba(74, 111, 165, 0.7);
    }
    50% {
        transform: scale(1.05);
        box-shadow: 0 0 0 10px rgba(74, 111, 165, 0);
    }
    100% {
        transform: scale(1);
        box-shadow: 0 0 0 0 rgba(74, 111, 165, 0);
    }
}

@keyframes selectedJump {
    0%, 100% { 
        transform: translateY(0) scale(1);
    }
    25% {
        transform: translateY(-15px) scale(1.05);
    }
    50% {
        transform: translateY(0) scale(1.1);
    }
    75% {
        transform: translateY(-7px) scale(1.05);
    }
}

@keyframes selectedGlow {
    0% {
        filter: brightness(100%);
        border-color: var(--primary-color);
    }
    50% {
        filter: brightness(120%);
        border-color: #6a8fd4;
    }
    100% {
        filter: brightness(100%);
        border-color: var(--primary-color);
    }
}

.image-item.selected {
    animation: selectedPulse 1s ease-out, selectedGlow 1.5s ease-in-out;
    border: 3px solid var(--primary-color);
    z-index: 10;
    position: relative;
}

.image-item.highlight {
    animation: pulse 0.5s ease infinite alternate;
    border: 2px dashed var(--primary-color);
    opacity: 0.8;
}

.image-item.jump {
    animation: selectedJump 0.8s ease infinite;
    box-shadow: 0 10px 20px rgba(0,0,0,0.2);
    z-index: 5;
}

.image-item.selected-final {
    border: 3px solid var(--primary-color);
    box-shadow: 0 0 25px rgba(74, 111, 165, 0.7);
    transform: scale(1.08);
    transition: all 0.5s cubic-bezier(0.175, 0.885, 0.32, 1.275);
    z-index: 20;
}

.image-item.selected-final:hover {
    transform: scale(1.1);
    box-shadow: 0 0 30px rgba(74, 111, 165, 0.9);
}

.confetti {
    position: fixed;
    width: 8px;
    height: 8px;
    border-radius: 50%;
    pointer-events: none;
    z-index: 1000;
    transform-origin: center;
}

@media (max-width: 768px) {
    .container {
        padding: 1rem;
    }
    
    h1 {
        font-size: 2rem;
    }
    
    .random-controls {
        flex-direction: column;
    }
    
    .image-gallery {
        grid-template-columns: repeat(auto-fill, minmax(150px, 1fr));
    }
}

@media print {
    .upload-area, .language-switcher, .upload-controls, .random-section {
        display: none;
    }
    
    .image-gallery {
        grid-template-columns: repeat(4, 1fr);
    }
}

.empty-message {
    white-space: nowrap;
    text-align: center;
    color: var(--secondary-color);
    padding: 1rem;
}

/* 基础图片库布局 */
.image-gallery {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(30vw, 1fr));
    gap: 0.5rem;
    margin-top: 1rem;
}

/* 手机端样式 (最大480px宽度) */
@media (max-width: 480px) {
    .image-gallery {
        grid-template-columns: repeat(3, 1fr); /* 强制3列 */
        gap: 0.4rem;
    }
    
    .image-item {
        aspect-ratio: 1/1; /* 保持正方形 */
    }
    
    .remove-btn {
        width: 18px;
        height: 18px;
        font-size: 12px;
        top: 2px;
        right: 2px;
    }
}

/* 小屏幕平板 (481-768px) */
@media (min-width: 481px) and (max-width: 768px) {
    .image-gallery {
        grid-template-columns: repeat(auto-fill, minmax(25vw, 1fr));
        gap: 0.6rem;
    }
}

/* 桌面端 (769px以上) */
@media (min-width: 769px) {
    .image-gallery {
        grid-template-columns: repeat(auto-fill, minmax(150px, 1fr));
        gap: 0.8rem;
    }
}