:root {
    --primary-color: #4361ee;
    --primary-hover: #3a56d4;
    --secondary-color: #f8f9fa;
    --text-color: #2b2d42;
    --text-light: #6c757d;
    --success-color: #4cc9f0;
    --error-color: #f72585;
    --border-radius: 16px;
    --box-shadow: 0 15px 35px rgba(0, 0, 0, 0.1);
    --transition: all 0.3s cubic-bezier(0.25, 0.8, 0.25, 1);
    --gradient: linear-gradient(135deg, #4361ee 0%, #4cc9f0 100%);
}

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

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
    background: linear-gradient(135deg, #f8f9fa 0%, #e9ecef 100%);
    color: var(--text-color);
    line-height: 1.6;
    margin: 0;
    padding: 0;
    min-height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
}

.container {
    background-color: white;
    border-radius: var(--border-radius);
    box-shadow: var(--box-shadow);
    width: 90%;
    max-width: 500px;
    padding: 2.5rem;
    margin: 2rem 0;
    position: relative;
    overflow: hidden;
}

.container::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 5px;
    background: var(--gradient);
}

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

.header h1 {
    font-size: 2.2rem;
    font-weight: 700;
    margin-bottom: 0.5rem;
    background: var(--gradient);
    -webkit-background-clip: text;
    background-clip: text;
    color: transparent;
    letter-spacing: -0.5px;
}

.subtitle {
    color: var(--text-light);
    font-size: 0.95rem;
    font-weight: 400;
}

.tabs {
    display: flex;
    margin-bottom: 1.5rem;
    border-bottom: 1px solid rgba(0, 0, 0, 0.05);
    position: relative;
}

.tabs::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 100%;
    height: 1px;
    background: rgba(0, 0, 0, 0.05);
}

.tab-btn {
    padding: 0.75rem 1.5rem;
    background: none;
    border: none;
    cursor: pointer;
    font-size: 0.95rem;
    font-weight: 500;
    color: var(--text-light);
    transition: var(--transition);
    position: relative;
    display: flex;
    align-items: center;
    gap: 0.5rem;
    border-radius: 8px 8px 0 0;
}

.tab-btn:hover {
    color: var(--primary-color);
}

.tab-btn.active {
    color: var(--primary-color);
    font-weight: 600;
}

.tab-btn.active::after {
    content: '';
    position: absolute;
    bottom: -1px;
    left: 0;
    width: 100%;
    height: 3px;
    background: var(--gradient);
    border-radius: 3px 3px 0 0;
    z-index: 1;
}

.tab-content {
    display: none;
    animation: fadeIn 0.4s cubic-bezier(0.39, 0.575, 0.565, 1) both;
}

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(10px); }
    to { opacity: 1; transform: translateY(0); }
}

.upload-area {
    border: 2px dashed rgba(67, 97, 238, 0.3);
    border-radius: var(--border-radius);
    padding: 2.5rem 1.5rem;
    text-align: center;
    cursor: pointer;
    transition: var(--transition);
    margin-bottom: 1.5rem;
    background-color: rgba(67, 97, 238, 0.02);
    position: relative;
    overflow: hidden;
}

.upload-area:hover {
    border-color: var(--primary-color);
    background-color: rgba(67, 97, 238, 0.05);
    transform: translateY(-2px);
}

.upload-icon {
    font-size: 3.5rem;
    margin-bottom: 1rem;
    color: var(--primary-color);
    transition: var(--transition);
}

.upload-text {
    font-size: 1.15rem;
    margin-bottom: 1rem;
    color: var(--text-color);
    font-weight: 500;
}

.upload-hint {
    font-size: 0.85rem;
    color: var(--text-light);
    margin-top: 1rem;
    opacity: 0.8;
}

.btn {
    padding: 0.85rem 1.75rem;
    border-radius: 50px;
    cursor: pointer;
    font-size: 0.95rem;
    font-weight: 500;
    transition: var(--transition);
    border: none;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.05);
}

.primary-btn {
    background: var(--gradient);
    color: white;
    position: relative;
    overflow: hidden;
}

.primary-btn::after {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: linear-gradient(rgba(255,255,255,0.3), rgba(255,255,255,0));
    opacity: 0;
    transition: var(--transition);
}

.primary-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 12px rgba(67, 97, 238, 0.2);
}

.primary-btn:hover::after {
    opacity: 1;
}

.secondary-btn {
    background-color: white;
    color: var(--text-color);
    border: 1px solid rgba(0, 0, 0, 0.1);
}

.secondary-btn:hover {
    background-color: #f8f9fa;
    transform: translateY(-2px);
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.05);
}

.result-box {
    background-color: rgba(76, 201, 240, 0.08);
    border: 1px solid rgba(76, 201, 240, 0.2);
    border-radius: var(--border-radius);
    padding: 2.5rem;
    text-align: center;
    animation: fadeIn 0.5s ease;
    position: relative;
    overflow: hidden;
}

.result-box::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 5px;
    background: var(--gradient);
}

.success-icon {
    width: 70px;
    height: 70px;
    background: var(--gradient);
    color: white;
    border-radius: 50%;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    font-size: 2rem;
    font-weight: bold;
    margin-bottom: 1.5rem;
    box-shadow: 0 4px 12px rgba(67, 97, 238, 0.2);
}

.result-box h3 {
    color: var(--text-color);
    margin-bottom: 1.5rem;
    font-size: 1.4rem;
    font-weight: 600;
}

.pickup-code {
    background-color: white;
    border-radius: 8px;
    padding: 1rem;
    margin: 1.5rem 0;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    border: 1px solid rgba(0, 0, 0, 0.05);
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.03);
}

.pickup-code label {
    color: var(--text-light);
    font-size: 0.9rem;
}

.code {
    font-family: 'Courier New', monospace;
    font-size: 1.3rem;
    font-weight: 700;
    color: var(--primary-color);
    letter-spacing: 1px;
}

.result-message {
    color: var(--text-light);
    font-size: 0.9rem;
    margin-bottom: 1.5rem;
    opacity: 0.8;
}

.action-buttons {
    display: flex;
    gap: 1rem;
    justify-content: center;
}

.download-form {
    margin-bottom: 1.5rem;
}

.input-group {
    position: relative;
    margin-bottom: 1.5rem;
}

.input-group .icon {
    position: absolute;
    left: 1.25rem;
    top: 50%;
    transform: translateY(-50%);
    color: var(--text-light);
    font-size: 1.1rem;
}

#codeInput {
    width: 100%;
    padding: 0.85rem 1.25rem 0.85rem 3rem;
    border: 1px solid rgba(0, 0, 0, 0.1);
    border-radius: 50px;
    font-size: 0.95rem;
    transition: var(--transition);
    background-color: rgba(0, 0, 0, 0.02);
}

#codeInput:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(67, 97, 238, 0.2);
    background-color: white;
}

.error-message {
    color: var(--error-color);
    text-align: center;
    margin-top: 1rem;
    font-size: 0.9rem;
    font-weight: 500;
    min-height: 1.5rem;
    padding: 0.5rem 1rem;
    border-radius: 50px;
    background-color: rgba(247, 37, 133, 0.05);
    display: inline-block;
}

.footer {
    text-align: center;
    margin-top: 2rem;
    color: var(--text-light);
    font-size: 0.85rem;
    opacity: 0.7;
}

.footer a {
    color: var(--primary-color);
    text-decoration: none;
    font-weight: 500;
    transition: var(--transition);
}

.footer a:hover {
    text-decoration: underline;
    opacity: 1;
}

/* 进度条样式 */
.progress-bar {
    width: 100%;
    height: 6px;
    background-color: rgba(0, 0, 0, 0.05);
    border-radius: 3px;
    margin: 1.5rem 0;
    overflow: hidden;
}

.progress {
    height: 100%;
    background: var(--gradient);
    border-radius: 3px;
    transition: width 0.3s ease;
    width: 0%;
}

/* 响应式设计 */
@media (max-width: 576px) {
    .container {
        padding: 1.75rem;
    }
    
    .header h1 {
        font-size: 1.8rem;
    }
    
    .action-buttons {
        flex-direction: column;
        gap: 0.75rem;
    }
    
    .btn {
        width: 100%;
    }
    
    .upload-area {
        padding: 2rem 1rem;
    }
    
    .result-box {
        padding: 2rem 1.5rem;
    }
}

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
    background: #e6f2ff; /* 淡蓝色背景 */
    color: var(--text-color);
    line-height: 1.6;
    margin: 0;
    padding: 0;
    min-height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
}