/* Reset and base styles */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    --primary-color: #3498db;
    --secondary-color: #2ecc71;
    --accent-color: #f39c12;
    --dark-color: #2c3e50;
    --light-color: #ecf0f1;
    --danger-color: #e74c3c;
    --text-color: #333;
    --shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
    --transition: all 0.3s ease;
}

body {
    font-family: 'Segoe UI', 'Roboto', 'Helvetica Neue', Arial, sans-serif;
    line-height: 1.6;
    color: var(--text-color);
    background-color: #f8f9fa;
}

a {
    text-decoration: none;
    color: var(--primary-color);
    transition: var(--transition);
}

a:hover {
    color: var(--dark-color);
}

.container {
    width: 100%;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 15px;
}

/* Header */
.header {
    background-color: #fff;
    box-shadow: var(--shadow);
    position: sticky;
    top: 0;
    z-index: 100;
}

.header-container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1rem 0;
}

.logo {
    font-size: 1.5rem;
    font-weight: bold;
    color: var(--dark-color);
}

.logo span {
    color: var(--primary-color);
}

.nav-menu {
    display: flex;
    list-style: none;
}

.nav-menu li {
    margin-left: 1.5rem;
}

.nav-menu a {
    color: var(--dark-color);
    font-weight: 500;
}

.nav-menu a:hover {
    color: var(--primary-color);
}

/* Hero section */
.hero {
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    color: white;
    padding: 4rem 0;
    text-align: center;
}

.hero h1 {
    font-size: 2.5rem;
    margin-bottom: 1rem;
}

.hero p {
    font-size: 1.2rem;
    max-width: 700px;
    margin: 0 auto 2rem;
}

.btn {
    display: inline-block;
    background-color: var(--accent-color);
    color: white;
    padding: 0.8rem 2rem;
    border-radius: 4px;
    font-weight: 500;
    transition: var(--transition);
}

.btn:hover {
    background-color: #e67e22;
    color: white;
    transform: translateY(-3px);
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.2);
}

/* Tools grid */
.tools-section {
    padding: 4rem 0;
}

.section-title {
    text-align: center;
    margin-bottom: 3rem;
    position: relative;
}

.section-title h2 {
    font-size: 2rem;
    color: var(--dark-color);
}

.section-title::after {
    content: '';
    display: block;
    width: 80px;
    height: 4px;
    background: var(--primary-color);
    margin: 1rem auto 0;
}

.tools-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
    gap: 2rem;
}

.tool-card {
    background-color: white;
    border-radius: 8px;
    overflow: hidden;
    box-shadow: var(--shadow);
    transition: var(--transition);
}

.tool-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 10px 20px rgba(0, 0, 0, 0.1);
}

.tool-icon {
    height: 160px;
    background-color: var(--light-color);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 3rem;
    color: var(--primary-color);
}

.tool-content {
    padding: 1.5rem;
}

.tool-content h3 {
    margin-bottom: 0.5rem;
    color: var(--dark-color);
}

.tool-content p {
    color: #666;
    margin-bottom: 1rem;
}

/* Tool pages */
.tool-container {
    background-color: white;
    border-radius: 8px;
    box-shadow: var(--shadow);
    padding: 2rem;
    margin: 2rem 0;
}

.tool-header {
    margin-bottom: 2rem;
    padding-bottom: 1rem;
    border-bottom: 1px solid #eee;
}

.tool-header h2 {
    color: var(--dark-color);
    margin-bottom: 0.5rem;
}

.form-group {
    margin-bottom: 1.5rem;
}

.form-group label {
    display: block;
    margin-bottom: 0.5rem;
    font-weight: 500;
}

.form-control {
    width: 100%;
    padding: 0.8rem 1rem;
    border: 1px solid #ddd;
    border-radius: 4px;
    font-size: 1rem;
}

.form-control:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(52, 152, 219, 0.2);
}

.result-container {
    background-color: var(--light-color);
    padding: 1.5rem;
    border-radius: 4px;
    margin-top: 2rem;
}

/* Footer */
.footer {
    background-color: var(--dark-color);
    color: white;
    padding: 3rem 0;
}

.footer-container {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 2rem;
}

.footer-col h3 {
    margin-bottom: 1.5rem;
    font-size: 1.2rem;
}

.footer-col ul {
    list-style: none;
}

.footer-col ul li {
    margin-bottom: 0.8rem;
}

.footer-col a {
    color: #bbb;
}

.footer-col a:hover {
    color: white;
}

.footer-bottom {
    text-align: center;
    padding-top: 2rem;
    margin-top: 2rem;
    border-top: 1px solid rgba(255, 255, 255, 0.1);
    color: #bbb;
}

/* Responsive */
@media (max-width: 768px) {
    .header-container {
        flex-direction: column;
    }

    .nav-menu {
        margin-top: 1rem;
    }

    .nav-menu li {
        margin: 0 0.75rem;
    }

    .hero h1 {
        font-size: 2rem;
    }

    .hero p {
        font-size: 1rem;
    }
}

/* Tool-specific styles */
.calculator-wrapper {
    max-width: 600px;
    margin: 0 auto;
}

.tax-calculator .form-row {
    display: flex;
    flex-wrap: wrap;
    margin: 0 -10px;
}

.tax-calculator .form-col {
    flex: 1 0 250px;
    padding: 0 10px;
    margin-bottom: 1rem;
}

.vehicle-info-table {
    width: 100%;
    border-collapse: collapse;
    margin-top: 1rem;
}

.vehicle-info-table th,
.vehicle-info-table td {
    padding: 0.75rem;
    text-align: left;
    border-bottom: 1px solid #eee;
}

.vehicle-info-table th {
    background-color: var(--light-color);
    font-weight: 500;
}

.input-group {
    display: flex;
}

.input-group .form-control {
    border-top-right-radius: 0;
    border-bottom-right-radius: 0;
}

.input-group-append {
    display: flex;
}

.input-group-text {
    padding: 0.8rem 1rem;
    background-color: var(--light-color);
    border: 1px solid #ddd;
    border-left: none;
    border-top-right-radius: 4px;
    border-bottom-right-radius: 4px;
}

/* 应用场景区块样式 */
.use-cases-section .section-title h2 {
    font-size: 2rem;
    margin-bottom: 2rem;
}

.use-cases-section .bg-white {
    border: 1px solid #eee;
    transition: box-shadow 0.2s;
}

.use-cases-section .bg-white:hover {
    box-shadow: 0 2px 16px rgba(0, 0, 0, 0.06);
}

/* FAQ区块样式 */
.faq-section .section-title h2 {
    font-size: 2rem;
    margin-bottom: 2rem;
}

.faq-section .accordion-button {
    font-size: 1rem;
    font-weight: 500;
}

.faq-section .accordion-item {
    border: 1px solid #eee;
    border-radius: 0.5rem;
    margin-bottom: 1rem;
    background: #fff;
}

.faq-section .accordion-body {
    font-size: 0.98rem;
    color: #555;
}

/* 关于我们区块样式 */
.about-section {
    background: #f8f9fa;
}

.about-section .section-title h2 {
    font-size: 2rem;
    margin-bottom: 1.5rem;
}

.about-section p {
    font-size: 1.08rem;
    color: #444;
    line-height: 1.8;
    margin-bottom: 0;
}