* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    -webkit-tap-highlight-color: transparent;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
    background-color: #f5f5f7;
    color: #333;
    line-height: 1.6;
}

.container {
    max-width: 600px;
    margin: 0 auto;
    padding: 20px;
}

header {
    text-align: center;
    margin-bottom: 30px;
}

h1 {
    font-size: 1.5rem;
    color: #1d1d1f;
}

.upload-area {
    text-align: center;
    margin-bottom: 30px;
}

.btn {
    background-color: #007aff;
    color: white;
    border: none;
    padding: 12px 24px;
    font-size: 1rem;
    border-radius: 8px;
    cursor: pointer;
    transition: background-color 0.2s;
    font-weight: 500;
}

.btn:active {
    background-color: #0056b3;
}

.preview-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 10px;
}

.preview-item {
    position: relative;
    aspect-ratio: 1 / 1;
    border-radius: 8px;
    overflow: hidden;
    background-color: #ddd;
    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
}

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

/* 适配超小屏幕 */
@media (max-width: 320px) {
    .preview-grid {
        grid-template-columns: repeat(2, 1fr);
    }
}