/* 基础重置 */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background: linear-gradient(135deg, #f5f7fa 0%, #e4e7f1 100%);
    color: #333;
    min-height: 100vh;
    padding: 20px;
    display: flex;
    justify-content: center;
    align-items: center;
}

/* 容器样式 */
.container {
    width: 100%;
    max-width: 500px;
    background: white;
    border-radius: 16px;
    padding: 30px;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.08);
    text-align: center;
}

/* 头部样式 */
.header {
    margin-bottom: 25px;
}

.logo {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 15px;
    margin-bottom: 10px;
}

.logo-icon {
    font-size: 2.5rem;
    background: #eef5ff;
    width: 70px;
    height: 70px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    color: #4a6cf7;
    box-shadow: 0 4px 10px rgba(74, 108, 247, 0.15);
}

h1 {
    font-size: 2.2rem;
    font-weight: 700;
    color: #2d3748;
}

.subtitle {
    font-size: 1.2rem;
    color: #718096;
    margin-top: 10px;
}

/* 上传区域 */
.upload-area {
    border: 2px dashed #cbd5e0;
    border-radius: 12px;
    padding: 35px 20px;
    margin: 25px 0;
    transition: all 0.3s ease;
    background: #f8fafc;
    cursor: pointer;
}

.upload-area:hover, .upload-area.dragover {
    border-color: #4a6cf7;
    background: #f0f7ff;
    transform: translateY(-3px);
}

.upload-icon {
    font-size: 3.5rem;
    color: #a0aec0;
    margin-bottom: 15px;
    transition: all 0.3s ease;
}

.upload-area:hover .upload-icon, .upload-area.dragover .upload-icon {
    color: #4a6cf7;
    transform: scale(1.1);
}

.upload-hint {
    color: #718096;
    font-size: 1.1rem;
    margin-bottom: 15px;
}

/* 文件信息 */
.file-info {
    font-size: 1rem;
    color: #718096;
    padding: 12px;
    background: #edf2f7;
    border-radius: 8px;
    margin-top: 15px;
    transition: all 0.3s ease;
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
}

.file-info.file-selected {
    background: #e6fffa;
    color: #319795;
    font-weight: 500;
}

/* 按钮组 */
.button-group {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: 12px;
    margin-top: 20px;
}

.btn {
    padding: 14px 24px;
    border: none;
    border-radius: 10px;
    cursor: pointer;
    font-size: 1rem;
    font-weight: 600;
    transition: all 0.3s ease;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    min-width: 140px;
}

.btn:hover {
    transform: translateY(-3px);
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
}

.btn:active {
    transform: translateY(0);
}

.btn.primary {
    background: #4a6cf7;
    color: white;
}

.btn.primary:hover {
    background: #3a56e0;
}

.btn.success {
    background: #38a169;
    color: white;
}

.btn.success:hover {
    background: #2f855a;
}

.btn.secondary {
    background: #718096;
    color: white;
}

.btn.secondary:hover {
    background: #4a5568;
}

.btn-icon {
    font-size: 1.2rem;
}

/* 响应式设计 */
@media (max-width: 600px) {
    .container {
        padding: 20px;
        margin: 15px;
    }
    
    .logo {
        flex-direction: column;
        text-align: center;
    }
    
    h1 {
        font-size: 1.8rem;
    }
    
    .subtitle {
        font-size: 1rem;
    }
    
    .upload-area {
        padding: 25px 15px;
    }
    
    .upload-icon {
        font-size: 2.8rem;
    }
    
    .upload-hint {
        font-size: 0.95rem;
    }
    
    .btn {
        padding: 12px 18px;
        font-size: 0.95rem;
        min-width: 120px;
    }
    
    .button-group {
        flex-direction: column;
        gap: 10px;
    }
    
    .button-group .btn {
        width: 100%;
    }
}

@media (max-width: 400px) {
    .container {
        padding: 15px;
    }
    
    h1 {
        font-size: 1.6rem;
    }
    
    .btn {
        padding: 10px 15px;
        font-size: 0.9rem;
    }
}