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

/* 根变量定义 */
:root {
    --primary-color: #667eea;
    --secondary-color: #764ba2;
    --accent-color: #f093fb;
    --text-color: #333;
    --light-text: #666;
    --bg-color: #f8fafc;
    --white: #ffffff;
    --border-color: #e2e8f0;
    --shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 10px 25px rgba(0, 0, 0, 0.15);
    --border-radius: 12px;
    --transition: all 0.3s ease;
}

/* 基础样式 */
body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    line-height: 1.6;
    color: var(--text-color);
    background: var(--bg-color);
    font-size: 16px;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

/* 头部横幅样式 */
.hero-section {
    position: relative;
    height: 60vh;
    min-height: 400px;
    background: url('../images/tech-bg.jpg') center/cover;
    display: flex;
    align-items: center;
    justify-content: center;
    text-align: center;
    overflow: hidden;
}

.hero-overlay {
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: linear-gradient(135deg, 
        rgba(102, 126, 234, 0.9), 
        rgba(118, 75, 162, 0.8));
    z-index: 1;
}

.hero-content {
    position: relative;
    z-index: 2;
    color: var(--white);
    max-width: 800px;
    padding: 40px 20px;
}

.hero-title {
    font-size: 3.5rem;
    font-weight: 700;
    margin-bottom: 1rem;
    text-shadow: 2px 2px 4px rgba(0, 0, 0, 0.3);
    animation: fadeInUp 1s ease-out;
}

.hero-title i {
    margin-right: 15px;
    color: var(--accent-color);
}

.hero-subtitle {
    font-size: 1.4rem;
    font-weight: 300;
    opacity: 0.95;
    animation: fadeInUp 1s ease-out 0.3s both;
}

/* 动画定义 */
@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(30px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* 主要内容区域 */
.main-content {
    padding: 80px 0;
    background: var(--bg-color);
}

/* 活动信息区域 */
.event-info {
    margin-bottom: 60px;
}

.info-card {
    background: var(--white);
    border-radius: var(--border-radius);
    padding: 40px;
    box-shadow: var(--shadow);
    border: 1px solid var(--border-color);
}

.info-card h2 {
    font-size: 2rem;
    font-weight: 600;
    color: var(--primary-color);
    margin-bottom: 30px;
    display: flex;
    align-items: center;
    gap: 10px;
}

.info-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 30px;
    margin-bottom: 40px;
}

.info-item {
    display: flex;
    align-items: center;
    gap: 15px;
    padding: 20px;
    background: linear-gradient(135deg, #f8faff, #f1f5f9);
    border-radius: var(--border-radius);
    border-left: 4px solid var(--primary-color);
    transition: var(--transition);
}

.info-item:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow);
}

.info-item i {
    font-size: 1.8rem;
    color: var(--primary-color);
    flex-shrink: 0;
}

.info-item h3 {
    font-size: 1.1rem;
    font-weight: 600;
    margin-bottom: 5px;
    color: var(--text-color);
}

.info-item p {
    color: var(--light-text);
    font-size: 1rem;
}

/* 活动描述 */
.event-description h3 {
    font-size: 1.3rem;
    font-weight: 600;
    color: var(--secondary-color);
    margin-bottom: 20px;
    display: flex;
    align-items: center;
    gap: 10px;
}

.event-description p {
    color: var(--light-text);
    line-height: 1.7;
    margin-bottom: 15px;
}

.event-description ul {
    list-style: none;
    margin-top: 20px;
}

.event-description li {
    padding: 8px 0;
    color: var(--light-text);
    font-size: 1rem;
}

/* 报名表单区域 */
.registration-section {
    margin-bottom: 60px;
}

.form-card {
    background: var(--white);
    border-radius: var(--border-radius);
    padding: 40px;
    box-shadow: var(--shadow);
    border: 1px solid var(--border-color);
}

.form-card h2 {
    font-size: 2rem;
    font-weight: 600;
    color: var(--primary-color);
    margin-bottom: 15px;
    display: flex;
    align-items: center;
    gap: 10px;
}

.form-description {
    color: var(--light-text);
    margin-bottom: 30px;
    font-size: 1rem;
}

/* 表单样式 */
.registration-form {
    max-width: 600px;
}

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

.form-group label {
    display: block;
    font-weight: 500;
    color: var(--text-color);
    margin-bottom: 8px;
    font-size: 1rem;
    display: flex;
    align-items: center;
    gap: 8px;
}

.form-group label i {
    color: var(--primary-color);
    font-size: 1.1rem;
}

.required {
    color: #e53e3e;
    font-weight: 600;
}

.form-group input,
.form-group textarea {
    width: 100%;
    padding: 14px 16px;
    border: 2px solid var(--border-color);
    border-radius: 8px;
    font-size: 1rem;
    font-family: inherit;
    transition: var(--transition);
    background: var(--white);
}

.form-group input:focus,
.form-group textarea:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(102, 126, 234, 0.1);
}

.form-group textarea {
    resize: vertical;
    min-height: 120px;
}

/* 提交按钮 */
.submit-btn {
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    color: var(--white);
    border: none;
    padding: 16px 32px;
    font-size: 1.1rem;
    font-weight: 600;
    border-radius: 8px;
    cursor: pointer;
    transition: var(--transition);
    display: flex;
    align-items: center;
    gap: 10px;
    min-width: 160px;
    justify-content: center;
}

.submit-btn:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

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

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

/* 页脚样式 */
.footer {
    background: var(--text-color);
    color: var(--white);
    padding: 30px 0;
    text-align: center;
    margin-top: auto;
}

.footer p {
    margin: 5px 0;
}

.admin-link {
    color: var(--accent-color);
    text-decoration: none;
    transition: var(--transition);
    display: inline-flex;
    align-items: center;
    gap: 5px;
}

.admin-link:hover {
    color: var(--white);
}

/* 模态框样式 */
.modal {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.5);
    z-index: 1000;
    animation: fadeIn 0.3s ease;
}

.modal-content {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    background: var(--white);
    border-radius: var(--border-radius);
    padding: 0;
    box-shadow: var(--shadow-lg);
    max-width: 500px;
    width: 90%;
    animation: slideIn 0.3s ease;
}

@keyframes fadeIn {
    from { opacity: 0; }
    to { opacity: 1; }
}

@keyframes slideIn {
    from {
        opacity: 0;
        transform: translate(-50%, -60%);
    }
    to {
        opacity: 1;
        transform: translate(-50%, -50%);
    }
}

.modal-header {
    padding: 30px 30px 20px;
    text-align: center;
    border-bottom: 1px solid var(--border-color);
}

.success-icon {
    font-size: 3rem;
    color: #28a745;
    margin-bottom: 15px;
}

.modal-header h3 {
    font-size: 1.5rem;
    font-weight: 600;
    color: var(--text-color);
}

.modal-body {
    padding: 20px 30px;
    text-align: center;
    color: var(--light-text);
}

.modal-body p {
    margin-bottom: 10px;
    line-height: 1.6;
}

.modal-footer {
    padding: 20px 30px 30px;
    text-align: center;
}

.modal-btn {
    background: var(--primary-color);
    color: var(--white);
    border: none;
    padding: 12px 24px;
    border-radius: 6px;
    font-size: 1rem;
    font-weight: 500;
    cursor: pointer;
    transition: var(--transition);
    min-width: 100px;
}

.modal-btn:hover {
    background: var(--secondary-color);
}

/* 响应式设计 */
@media (max-width: 768px) {
    .hero-title {
        font-size: 2.5rem;
    }
    
    .hero-subtitle {
        font-size: 1.2rem;
    }
    
    .hero-content {
        padding: 20px;
    }
    
    .info-card,
    .form-card {
        padding: 25px;
        margin: 0 10px;
    }
    
    .info-grid {
        grid-template-columns: 1fr;
        gap: 20px;
    }
    
    .container {
        padding: 0 15px;
    }
    
    .main-content {
        padding: 40px 0;
    }
}

@media (max-width: 480px) {
    .hero-title {
        font-size: 2rem;
    }
    
    .hero-subtitle {
        font-size: 1rem;
    }
    
    .info-card h2,
    .form-card h2 {
        font-size: 1.5rem;
    }
    
    .info-card,
    .form-card {
        padding: 20px;
    }
    
    .modal-content {
        width: 95%;
    }
}