/* 全局样式 */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    --primary-color: #007AFF;
    --primary-hover: #0056CC;
    --success-color: #34C759;
    --error-color: #FF3B30;
    --warning-color: #FF9500;
    --background: #F2F2F7;
    --surface: #FFFFFF;
    --text-primary: #000000;
    --text-secondary: #6D6D70;
    --border: #C6C6C8;
    --shadow: rgba(0, 0, 0, 0.1);
    --border-radius: 12px;
    --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    min-height: 100vh;
    color: var(--text-primary);
    line-height: 1.6;
}

.container {
    max-width: 600px;
    margin: 0 auto;
    padding: 20px;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

/* 头部样式 */
header {
    text-align: center;
    margin-bottom: 40px;
    padding: 40px 0;
}

header h1 {
    font-size: 2.5rem;
    font-weight: 700;
    color: white;
    margin-bottom: 10px;
    text-shadow: 0 2px 4px rgba(0, 0, 0, 0.3);
}

.subtitle {
    font-size: 1.1rem;
    color: rgba(255, 255, 255, 0.9);
    font-weight: 400;
}

/* 主要内容 */
main {
    flex: 1;
    display: flex;
    flex-direction: column;
    gap: 30px;
}

.form-container {
    background: var(--surface);
    border-radius: var(--border-radius);
    padding: 30px;
    box-shadow: 0 10px 30px var(--shadow);
    backdrop-filter: blur(10px);
    border: 1px solid rgba(255, 255, 255, 0.2);
}

.form-group {
    margin-bottom: 25px;
}

label {
    display: block;
    margin-bottom: 8px;
    font-weight: 600;
    color: var(--text-primary);
    font-size: 0.95rem;
}

select, input[type="email"] {
    width: 100%;
    padding: 16px;
    border: 2px solid var(--border);
    border-radius: 10px;
    font-size: 16px;
    background: var(--surface);
    color: var(--text-primary);
    transition: var(--transition);
    outline: none;
}

select:focus, input[type="email"]:focus {
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(0, 122, 255, 0.1);
}

select {
    cursor: pointer;
    appearance: none;
    background-image: url("data:image/svg+xml;charset=UTF-8,%3csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24' fill='none' stroke='currentColor' stroke-width='2' stroke-linecap='round' stroke-linejoin='round'%3e%3cpolyline points='6,9 12,15 18,9'%3e%3c/polyline%3e%3c/svg%3e");
    background-repeat: no-repeat;
    background-position: right 12px center;
    background-size: 20px;
    padding-right: 50px;
}

.help-text {
    display: block;
    margin-top: 5px;
    font-size: 0.85rem;
    color: var(--text-secondary);
}

.submit-btn {
    width: 100%;
    padding: 18px;
    background: var(--primary-color);
    color: white;
    border: none;
    border-radius: 10px;
    font-size: 1.1rem;
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition);
    position: relative;
    overflow: hidden;
}

.submit-btn:hover:not(:disabled) {
    background: var(--primary-hover);
    transform: translateY(-2px);
    box-shadow: 0 10px 25px rgba(0, 122, 255, 0.3);
}

.submit-btn:disabled {
    opacity: 0.7;
    cursor: not-allowed;
    transform: none;
}

.btn-loading {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 10px;
}

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

@keyframes spin {
    to {
        transform: rotate(360deg);
    }
}

/* 消息样式 */
.message {
    padding: 16px 20px;
    border-radius: 10px;
    font-weight: 500;
    text-align: center;
    margin-top: 20px;
    opacity: 0;
    transform: translateY(10px);
    transition: var(--transition);
}

.message.show {
    opacity: 1;
    transform: translateY(0);
}

.message.success {
    background: rgba(52, 199, 89, 0.1);
    color: var(--success-color);
    border: 1px solid rgba(52, 199, 89, 0.3);
}

.message.error {
    background: rgba(255, 59, 48, 0.1);
    color: var(--error-color);
    border: 1px solid rgba(255, 59, 48, 0.3);
}

/* 底部须知 */
footer {
    margin-top: 40px;
}

.notice {
    background: rgba(255, 255, 255, 0.95);
    border-radius: var(--border-radius);
    padding: 25px;
    backdrop-filter: blur(10px);
}

.notice h3 {
    color: var(--warning-color);
    margin-bottom: 15px;
    font-size: 1.1rem;
}

.notice ul {
    list-style: none;
    color: var(--text-secondary);
}

.notice li {
    padding: 5px 0;
    position: relative;
    padding-left: 20px;
}

.notice li::before {
    content: '•';
    color: var(--warning-color);
    position: absolute;
    left: 0;
    font-weight: bold;
}

/* 响应式设计 */
@media (max-width: 768px) {
    .container {
        padding: 15px;
    }
    
    header h1 {
        font-size: 2rem;
    }
    
    .form-container {
        padding: 20px;
    }
    
    select, input[type="email"] {
        padding: 14px;
        font-size: 16px; /* 防止iOS缩放 */
    }
    
    .submit-btn {
        padding: 16px;
    }
}

@media (max-width: 480px) {
    header h1 {
        font-size: 1.8rem;
    }
    
    .subtitle {
        font-size: 1rem;
    }
}

/* 暗色模式支持 */
@media (prefers-color-scheme: dark) {
    :root {
        --background: #1C1C1E;
        --surface: #2C2C2E;
        --text-primary: #FFFFFF;
        --text-secondary: #8E8E93;
        --border: #38383A;
    }
}