:root {
    --primary-color: #2c7be5;
    --primary-dark: #1a5fc1;
    --primary-light: #e8f2ff;
    --secondary-color: #6c757d;
    --success-color: #27b345;
    --warning-color: #fd7e14;
    --danger-color: #d92525;
    --light-color: #f8f9fa;
    --dark-color: #333;
    --border-color: #e4e7ed;
    --card-shadow: 0 8px 25px rgba(0, 0, 0, 0.1);
    --hover-shadow: 0 15px 35px rgba(0, 0, 0, 0.15);
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Segoe UI', 'Microsoft YaHei', sans-serif;
}

body {
    color: white;
    line-height: 1.6;
    min-height: 100vh;
    padding: 20px;
    position: relative;
}

.background-overlay {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: linear-gradient(135deg, rgba(44, 123, 229, 0.2), rgba(26, 95, 193, 0.3));
    z-index: -1;
}

.app-container {
    max-width: 1400px;
    margin: 0 auto;
    position: relative;
    z-index: 1;
}

.header {
    text-align: center;
    margin-bottom: 60px;
    padding: 40px 0;
    position: relative;
}

.header::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 25%;
    right: 25%;
    height: 3px;
    background: linear-gradient(90deg, transparent, var(--primary-color), transparent);
}

.logo {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 20px;
    margin-bottom: 20px;
}

.logo i {
    color: var(--primary-color);
    font-size: 48px;
    filter: drop-shadow(0 0 10px rgba(44, 123, 229, 0.5));
}

.logo h1 {
    font-size: 42px;
    font-weight: 800;
    background: linear-gradient(90deg, #fff, var(--primary-light));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    text-shadow: 0 2px 10px rgba(0, 0, 0, 0.3);
}

.subtitle {
    color: rgba(255, 255, 255, 0.85);
    font-size: 18px;
    max-width: 600px;
    margin: 0 auto;
    font-weight: 300;
}

.main-content {
    animation: fadeIn 0.8s ease-out;
}

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(20px); }
    to { opacity: 1; transform: translateY(0); }
}

.welcome-section {
    background: rgba(255, 255, 255, 0.1);
    backdrop-filter: blur(10px);
    border-radius: 20px;
    padding: 40px;
    margin-bottom: 40px;
    border: 1px solid rgba(255, 255, 255, 0.2);
}

.welcome-section h2 {
    display: flex;
    align-items: center;
    gap: 15px;
    font-size: 28px;
    margin-bottom: 20px;
    color: white;
}

.welcome-section h2 i {
    color: var(--primary-color);
}

.welcome-text {
    font-size: 17px;
    line-height: 1.8;
    color: rgba(255, 255, 255, 0.9);
    max-width: 800px;
}

.cards-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
    gap: 30px;
    margin-bottom: 50px;
}

.feature-card {
    background: rgba(255, 255, 255, 0.95);
    border-radius: 20px;
    padding: 30px;
    transition: all 0.3s ease;
    border: 1px solid rgba(255, 255, 255, 0.3);
    box-shadow: var(--card-shadow);
    display: flex;
    flex-direction: column;
    height: 100%;
    color: var(--dark-color);
}

.feature-card:hover {
    transform: translateY(-10px);
    box-shadow: var(--hover-shadow);
    border-color: var(--primary-color);
}

#epp-calculator-card {
    border-top: 5px solid var(--primary-color);
}

#tools-card {
    border-top: 5px solid var(--warning-color);
}

#company-card {
    border-top: 5px solid var(--success-color);
}

#support-card {
    border-top: 5px solid #6f42c1;
}

.card-icon {
    font-size: 48px;
    margin-bottom: 20px;
}

#epp-calculator-card .card-icon i {
    color: var(--primary-color);
}

#tools-card .card-icon i {
    color: var(--warning-color);
}

#company-card .card-icon i {
    color: var(--success-color);
}

#support-card .card-icon i {
    color: #6f42c1;
}

.card-content {
    flex: 1;
}

.card-content h3 {
    font-size: 22px;
    margin-bottom: 15px;
    color: var(--dark-color);
}

.card-content p {
    color: var(--secondary-color);
    margin-bottom: 20px;
    line-height: 1.6;
}

.feature-list {
    list-style: none;
    margin-top: 15px;
}

.feature-list li {
    display: flex;
    align-items: center;
    gap: 10px;
    margin-bottom: 10px;
    color: var(--secondary-color);
    font-size: 14px;
}

.feature-list li i {
    color: var(--success-color);
    font-size: 16px;
}

.company-info {
    margin-top: 20px;
}

.info-item {
    display: flex;
    align-items: center;
    gap: 10px;
    margin-bottom: 10px;
    font-size: 14px;
}

.info-item i {
    color: var(--primary-color);
    width: 20px;
}

.card-actions {
    display: flex;
    gap: 15px;
    margin-top: 25px;
    flex-wrap: wrap;
}

.btn {
    padding: 12px 24px;
    border: none;
    border-radius: 10px;
    font-weight: 600;
    cursor: pointer;
    display: inline-flex;
    align-items: center;
    gap: 10px;
    transition: all 0.3s;
    font-size: 14px;
    text-decoration: none;
    flex: 1;
    justify-content: center;
    min-width: 120px;
}

.btn-primary {
    background: linear-gradient(135deg, var(--primary-color), var(--primary-dark));
    color: white;
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 5px 15px rgba(44, 123, 229, 0.4);
}

.btn-outline {
    background-color: transparent;
    color: var(--primary-color);
    border: 2px solid var(--primary-color);
}

.btn-outline:hover {
    background-color: rgba(44, 123, 229, 0.1);
}

.quick-access {
    background: rgba(255, 255, 255, 0.1);
    backdrop-filter: blur(10px);
    border-radius: 20px;
    padding: 30px;
    margin-bottom: 40px;
    border: 1px solid rgba(255, 255, 255, 0.2);
}

.quick-access h3 {
    display: flex;
    align-items: center;
    gap: 15px;
    font-size: 24px;
    margin-bottom: 25px;
    color: white;
}

.quick-access h3 i {
    color: var(--primary-color);
}

.quick-buttons {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 20px;
}

.quick-btn {
    background: rgba(255, 255, 255, 0.9);
    border: none;
    border-radius: 15px;
    padding: 25px 20px;
    text-align: center;
    cursor: pointer;
    transition: all 0.3s;
    text-decoration: none;
    color: var(--dark-color);
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 15px;
}

.quick-btn:hover {
    background: white;
    transform: translateY(-5px);
    box-shadow: var(--hover-shadow);
}

.quick-btn i {
    font-size: 36px;
    color: var(--primary-color);
}

.quick-btn span {
    font-weight: 600;
    font-size: 16px;
}

.footer {
    margin-top: 60px;
    padding-top: 40px;
    border-top: 1px solid rgba(255, 255, 255, 0.2);
}

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

.footer-section h4 {
    color: white;
    margin-bottom: 15px;
    font-size: 18px;
}

.footer-section p {
    color: rgba(255, 255, 255, 0.7);
    margin-bottom: 10px;
    font-size: 14px;
}

.footer-bottom {
    text-align: center;
    padding-top: 20px;
    border-top: 1px solid rgba(255, 255, 255, 0.1);
    color: rgba(255, 255, 255, 0.6);
    font-size: 14px;
}

/* 模态框样式 */
.modal {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(0, 0, 0, 0.8);
    z-index: 1000;
    align-items: center;
    justify-content: center;
    backdrop-filter: blur(5px);
}

.modal-content {
    background: white;
    border-radius: 20px;
    width: 90%;
    max-width: 500px;
    overflow: hidden;
    box-shadow: 0 25px 50px rgba(0, 0, 0, 0.3);
    animation: modalSlideIn 0.3s ease;
}

@keyframes modalSlideIn {
    from { transform: translateY(-50px); opacity: 0; }
    to { transform: translateY(0); opacity: 1; }
}

.modal-header {
    background: linear-gradient(90deg, var(--primary-color), var(--primary-dark));
    color: white;
    padding: 20px 30px;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.modal-header h3 {
    display: flex;
    align-items: center;
    gap: 10px;
}

.modal-close {
    background: none;
    border: none;
    color: white;
    font-size: 28px;
    cursor: pointer;
    line-height: 1;
}

.modal-body {
    padding: 30px;
    color: var(--dark-color);
    line-height: 1.6;
}

.modal-footer {
    padding: 20px 30px;
    background: var(--light-color);
    display: flex;
    justify-content: flex-end;
    gap: 15px;
}

/* 响应式设计 */
@media (max-width: 768px) {
    .logo h1 {
        font-size: 32px;
    }
    
    .cards-grid {
        grid-template-columns: 1fr;
    }
    
    .card-actions {
        flex-direction: column;
    }
    
    .quick-buttons {
        grid-template-columns: repeat(2, 1fr);
    }
}

@media (max-width: 480px) {
    .quick-buttons {
        grid-template-columns: 1fr;
    }
    
    .welcome-section,
    .quick-access {
        padding: 25px;
    }
    
    .header {
        margin-bottom: 30px;
    }
}