/* 重置样式 */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

/* 基础样式 */
body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'PingFang SC', 'Hiragino Sans GB', 'Microsoft YaHei', sans-serif;
    line-height: 1.6;
    color: #333;
    background-color: #f5f5f5;
}

/* 容器 */
.container {
    max-width: 800px;
    margin: 0 auto;
    padding: 20px;
    background-color: #fff;
    min-height: 100vh;
}

/* 头部 */
.header {
    text-align: center;
    margin-bottom: 40px;
    padding: 30px 0;
    border-bottom: 2px solid #e9ecef;
}

.header__title {
    font-size: 2.5rem;
    color: #2c3e50;
    margin-bottom: 10px;
    font-weight: 600;
}

.header__subtitle {
    font-size: 1.1rem;
    color: #6c757d;
    margin: 0;
}

/* 主要内容 */
.main {
    margin-bottom: 40px;
}

/* 表单样式 */
.form {
    max-width: 100%;
}

.form__group {
    margin-bottom: 24px;
}

.form__label {
    display: block;
    margin-bottom: 8px;
    font-weight: 500;
    color: #2c3e50;
    font-size: 0.95rem;
}

.form__input,
.form__textarea,
.form__select {
    width: 100%;
    padding: 12px 16px;
    border: 2px solid #e9ecef;
    border-radius: 8px;
    font-size: 1rem;
    transition: all 0.3s ease;
    background-color: #fff;
}

.form__input:focus,
.form__textarea:focus,
.form__select:focus {
    outline: none;
    border-color: #007bff;
    box-shadow: 0 0 0 3px rgba(0, 123, 255, 0.1);
}

.form__input:invalid:not(:focus):not(:placeholder-shown),
.form__textarea:invalid:not(:focus):not(:placeholder-shown),
.form__select:invalid:not(:focus) {
    border-color: #dc3545;
}

.form__input[readonly] {
    background-color: #f5f5f5;
    color: #666;
    cursor: not-allowed;
    border-color: #ddd;
}

/* 禁用的选项样式 */
.form__select option:disabled {
    color: #ccc !important;
    background-color: #f5f5f5 !important;
}

.form__textarea {
    resize: vertical;
    min-height: 100px;
}

.form__select {
    cursor: pointer;
}

.form__help {
    display: block;
    margin-top: 4px;
    font-size: 0.875rem;
    color: #6c757d;
}

.form__error {
    display: block;
    margin-top: 4px;
    font-size: 0.875rem;
    color: #dc3545;
    min-height: 20px;
}

/* 单选按钮组 */
.form__radio-group {
    display: flex;
    gap: 20px;
    margin-top: 8px;
    padding: 8px;
    border-radius: 6px;
    transition: all 0.3s ease;
}

.form__radio-group--error {
    background-color: #fff5f5;
    border: 1px solid #dc3545;
}

.form__radio {
    display: flex;
    align-items: center;
    cursor: pointer;
    font-size: 1rem;
}

.form__radio input[type="radio"] {
    margin-right: 8px;
    width: 18px;
    height: 18px;
    cursor: pointer;
}

.form__radio-text {
    color: #2c3e50;
}

/* 按钮样式 */
.form__actions {
    margin-top: 40px;
    text-align: center;
}

.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 14px 32px;
    border: none;
    border-radius: 8px;
    font-size: 1.1rem;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.3s ease;
    text-decoration: none;
    min-width: 160px;
    position: relative;
}

.btn--primary {
    background-color: #007bff;
    color: #fff;
}

.btn--primary:hover:not(:disabled) {
    background-color: #0056b3;
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(0, 123, 255, 0.3);
}

.btn--secondary {
    background-color: #6c757d;
    color: #fff;
}

.btn--secondary:hover:not(:disabled) {
    background-color: #545b62;
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(108, 117, 125, 0.3);
}

.btn:disabled {
    opacity: 0.6;
    cursor: not-allowed;
    transform: none;
    box-shadow: none;
}

.btn__loading {
    position: absolute;
    left: 50%;
    top: 50%;
    transform: translate(-50%, -50%);
}

.btn__icon {
    margin-right: 8px;
    font-size: 1rem;
}

/* 消息提示 */
.message {
    padding: 20px;
    border-radius: 8px;
    margin: 20px 0;
    text-align: center;
}

.message--success {
    background-color: #d4edda;
    border: 1px solid #c3e6cb;
    color: #155724;
}

.message--error {
    background-color: #f8d7da;
    border: 1px solid #f5c6cb;
    color: #721c24;
}

.message h3 {
    margin-bottom: 10px;
    font-size: 1.2rem;
}

.message p {
    margin: 0 0 20px 0;
    font-size: 1rem;
}

.message__actions {
    display: flex;
    gap: 15px;
    justify-content: center;
    margin-top: 20px;
}

/* 响应式设计 */
@media (max-width: 768px) {
    .container {
        padding: 15px;
        margin: 0;
        border-radius: 0;
    }
    
    .header {
        padding: 20px 0;
        margin-bottom: 30px;
    }
    
    .header__title {
        font-size: 2rem;
    }
    
    .header__subtitle {
        font-size: 1rem;
    }
    
    .form__group {
        margin-bottom: 20px;
    }
    
    .form__input,
    .form__textarea,
    .form__select {
        padding: 10px 14px;
        font-size: 16px; /* 防止iOS缩放 */
    }
    
    .form__radio-group {
        flex-direction: column;
        gap: 12px;
    }
    
    .btn {
        width: 100%;
        padding: 16px 24px;
        font-size: 1.1rem;
    }
    
    .message__actions {
        flex-direction: column;
        gap: 12px;
    }
    
    .message__actions .btn {
        width: 100%;
    }
    
    .form__actions {
        margin-top: 30px;
    }
}

@media (max-width: 480px) {
    .container {
        padding: 10px;
    }
    
    .header__title {
        font-size: 1.8rem;
    }
    
    .form__input,
    .form__textarea,
    .form__select {
        padding: 12px;
    }
}

/* 加载动画 */
@keyframes spin {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
}

.btn__loading::after {
    content: '';
    width: 16px;
    height: 16px;
    border: 2px solid #ffffff;
    border-top: 2px solid transparent;
    border-radius: 50%;
    animation: spin 1s linear infinite;
}

/* 表单验证状态 */
.form__input--valid,
.form__textarea--valid,
.form__select--valid {
    border-color: #28a745;
}

.form__input--invalid,
.form__textarea--invalid,
.form__select--invalid {
    border-color: #dc3545;
}

/* 焦点可访问性 */
.form__input:focus-visible,
.form__textarea:focus-visible,
.form__select:focus-visible,
.btn:focus-visible {
    outline: 2px solid #007bff;
    outline-offset: 2px;
}

/* 打印样式 */
@media print {
    .btn,
    .message {
        display: none;
    }
    
    .container {
        box-shadow: none;
        padding: 0;
    }
    
    .form__input,
    .form__textarea,
    .form__select {
        border: 1px solid #000;
        background: transparent;
    }
}