* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
}

:root {
    --primary-color: #3498db;
    --secondary-color: #2c3e50;
    --bg-color: #F5F5F5;
    --card-color: #FFFFFF;
    --text-primary: #333333;
    --text-secondary: #666666;
    --text-light: #999999;
    --border-color: #000000;
    --divider-color: #E5E5E5;
    font-size: clamp(0.875rem, 2vw, 1rem); /* 14-16px */
}

body {
    background-color: var(--bg-color);
    color: var(--text-primary);
    min-height: 100vh;
}

/* 顶部导航 */
.header {
    background: var(--primary-color);
    color: white;
    padding: clamp(0.75rem, 2vw, 0.9375rem);
    display: flex;
    align-items: center;
    position: sticky;
    top: 0;
    z-index: 100;
}

.back-btn {
    color: white;
    font-size: clamp(1.25rem, 3vw, 1.5rem);
    background: none;
    border: none;
    cursor: pointer;
    padding: 0.25rem;
}

.header-title {
    font-size: clamp(1.5rem, 3vw, 2rem);
    font-weight: 500;
    text-align: center;
    flex: 1;
}

/* 主要内容区 */
.container {
    padding: clamp(1rem, 3vw, 1.25rem);
    max-width: 50rem;
    margin: 0 auto;
}

/* 页面标题 */
.page-header {
    text-align: center;
    margin-bottom: clamp(2rem, 5vw, 3rem);
}

.page-title {
    font-size: clamp(1.5rem, 4vw, 2rem);
    font-weight: 600;
    margin-bottom: 0.75rem;
    color: var(--text-primary);
}

.page-subtitle {
    color: var(--text-secondary);
    font-size: clamp(1rem, 2.5vw, 1.125rem);
    max-width: 40rem;
    margin: 0 auto;
    line-height: 1.6;
}

/* 表单卡片 */
.form-card {
    background: var(--card-color);
    border-radius: 1rem;
    padding: clamp(1.5rem, 4vw, 2.5rem);
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.08);
    border: 0.0625rem solid var(--border-color);
    margin-bottom: 2rem;
}

.form-title {
    font-size: clamp(1.125rem, 3vw, 1.5rem);
    font-weight: 600;
    margin-bottom: 1.5rem;
    padding-bottom: 0.75rem;
    border-bottom: 0.125rem solid var(--primary-color);
    color: var(--text-primary);
}

/* 表单样式 */
.form-group {
    margin-bottom: 1.75rem;
}

.form-label {
    display: block;
    margin-bottom: 0.625rem;
    font-weight: 500;
    color: var(--text-primary);
    font-size: clamp(0.95rem, 2.5vw, 1.05rem);
}

.required::after {
    content: " *";
    color: #FA5151;
}

.form-input,
.form-select {
    width: 100%;
    padding: 0.875rem 1.25rem;
    border: 0.0625rem solid var(--border-color);
    border-radius: 0.625rem;
    font-size: clamp(0.95rem, 2.5vw, 1.05rem);
    color: var(--text-primary);
    transition: all 0.2s;
    background-color: white;
}

.form-input:focus,
.form-select:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 0.1875rem rgba(7, 193, 96, 0.15);
}

.form-select {
    appearance: none;
    background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='16' height='16' viewBox='0 0 24 24' fill='none' stroke='%23666' stroke-width='2' stroke-linecap='round' stroke-linejoin='round'%3E%3Cpath d='M6 9l6 6 6-6'/%3E%3C/svg%3E");
    background-repeat: no-repeat;
    background-position: right 1.25rem center;
    background-size: 1rem;
}

.form-row {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 1.25rem;
    margin-bottom: 1.75rem;
}

.form-hint {
    font-size: clamp(0.85rem, 2.2vw, 0.95rem);
    color: var(--text-light);
    margin-top: 0.375rem;
    line-height: 1.5;
}

/* 专用发票额外字段 */
.special-invoice-fields {
    background: rgba(250, 173, 20, 0.05);
    border: 1px solid rgba(250, 173, 20, 0.2);
    border-radius: 0.75rem;
    padding: 1.75rem;
    margin-top: 1.5rem;
    margin-bottom: 2rem;
    animation: fadeIn 0.3s ease;
}

.special-title {
    font-size: 1.125rem;
    font-weight: 600;
    color: var(--warning-color);
    margin-bottom: 1.25rem;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.special-title::before {
    content: "⚠️";
    font-size: 1.25rem;
}

/* 操作按钮 */
.actions-section {
    display: flex;
    justify-content: center;
    gap: 1.25rem;
    margin-top: 3rem;
}

.btn {
    padding: clamp(0.875rem, 2.5vw, 1.125rem) clamp(2rem, 5vw, 3rem);
    border-radius: 0.75rem;
    font-size: clamp(1rem, 2.5vw, 1.125rem);
    font-weight: 500;
    cursor: pointer;
    border: none;
    transition: all 0.3s;
    min-width: 10rem;
}

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

.btn-primary:hover {
    background: #06b057;
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(7, 193, 96, 0.25);
}

.btn-secondary {
    background: white;
    color: var(--primary-color);
    border: 0.125rem solid var(--primary-color);
}

.btn-secondary:hover {
    background: #f8f9fa;
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(7, 193, 96, 0.1);
}

/* 保存成功提示 */
.success-message {
    background: rgba(82, 196, 26, 0.1);
    border: 1px solid rgba(82, 196, 26, 0.3);
    border-radius: 0.75rem;
    padding: 1.5rem;
    margin-top: 2rem;
    text-align: center;
    display: none;
    animation: fadeIn 0.5s ease;
}

.success-message.show {
    display: block;
}

.success-icon {
    font-size: 2.5rem;
    margin-bottom: 1rem;
    color: var(--success-color);
}

.success-text {
    color: var(--success-color);
    font-weight: 500;
    font-size: 1.125rem;
    margin-bottom: 0.5rem;
}

.success-subtext {
    color: var(--text-secondary);
    font-size: 0.95rem;
}

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

/* 响应式调整 */
@media (max-width: 48rem) {
    .container {
        padding: 1rem;
    }
    
    .form-card {
        padding: 1.5rem;
    }
    
    .form-row {
        grid-template-columns: 1fr;
    }
    
    .actions-section {
        flex-direction: column;
        align-items: stretch;
    }
    
    .btn {
        width: 100%;
        min-width: auto;
    }
    
    .special-invoice-fields {
        padding: 1.25rem;
    }
}

@media (max-width: 30rem) {
    .page-header {
        margin-bottom: 1.5rem;
    }
    
    .form-card {
        padding: 1.25rem;
    }
}