/* Base Styles */
:root {
    --primary-color: #3498db;
    --secondary-color: #2ecc71;
    --accent-color: #f39c12;
    --dark-color: #34495e;
    --light-color: #ecf0f1;
    --text-color: #333;
    --light-text-color: #7f8c8d;
    --border-color: #e0e0e0;
    --shadow-color: rgba(0, 0, 0, 0.1);
    --success-color: #27ae60;
    --danger-color: #e74c3c;
    --info-color: #3498db;
    --warning-color: #f1c40f;
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: 'Microsoft YaHei', 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    line-height: 1.6;
    color: var(--text-color);
    background-color: var(--light-color);
}

.container {
    width: 90%;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 15px;
}

/* Typography */
h1, h2, h3, h4, h5, h6 {
    margin-bottom: 0.5em;
    font-weight: 700;
    line-height: 1.2;
}

h1 {
    font-size: 2.5rem;
}

h2 {
    font-size: 2rem;
}

h3 {
    font-size: 1.5rem;
}

h4 {
    font-size: 1.25rem;
}

p {
    margin-bottom: 1rem;
}

ul, ol {
    margin-bottom: 1rem;
    padding-left: 1.5rem;
}

a {
    color: var(--primary-color);
    text-decoration: none;
    transition: color 0.3s;
}

a:hover {
    color: darken(var(--primary-color), 10%);
}

/* Header Styles */
.header {
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    color: white;
    padding: 3rem 0;
    text-align: center;
    box-shadow: 0 2px 10px var(--shadow-color);
}

.header h1 {
    font-size: 2.8rem;
    margin-bottom: 0.5rem;
    text-shadow: 1px 1px 3px rgba(0, 0, 0, 0.2);
}

.header h2 {
    font-size: 1.8rem;
    font-weight: 400;
    margin-bottom: 2rem;
    text-shadow: 1px 1px 3px rgba(0, 0, 0, 0.2);
}

.presenter-info {
    margin-top: 1.5rem;
    font-size: 1.1rem;
}

.presenter-info p {
    margin-bottom: 0.5rem;
}

/* Navigation */
.main-nav {
    background-color: white;
    box-shadow: 0 2px 5px var(--shadow-color);
    position: sticky;
    top: 0;
    z-index: 1000;
}

.main-nav ul {
    display: flex;
    list-style: none;
    padding: 0;
    margin: 0;
    overflow-x: auto;
}

.main-nav li {
    flex: 0 0 auto;
}

.main-nav a {
    display: block;
    padding: 1rem 1.5rem;
    color: var(--dark-color);
    font-weight: 600;
    transition: all 0.3s;
    white-space: nowrap;
}

.main-nav a:hover {
    background-color: rgba(52, 152, 219, 0.1);
    color: var(--primary-color);
}

/* Main Content */
.main-content {
    padding: 3rem 0;
}

.section {
    margin-bottom: 4rem;
    background-color: white;
    border-radius: 8px;
    box-shadow: 0 2px 15px var(--shadow-color);
    overflow: hidden;
}

.section-title {
    padding: 1.5rem;
    border-bottom: 1px solid var(--border-color);
    background-color: rgba(52, 152, 219, 0.05);
    color: var(--primary-color);
}

.section-content {
    padding: 2rem;
}

/* Introduction Section */
.intro-text {
    font-size: 1.2rem;
    margin-bottom: 1.5rem;
}

/* Purpose Cards */
.purpose-cards {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 2rem;
    margin-top: 2rem;
}

.card {
    background-color: white;
    border-radius: 8px;
    padding: 1.5rem;
    box-shadow: 0 2px 10px var(--shadow-color);
    transition: transform 0.3s, box-shadow 0.3s;
    text-align: center;
}

.card:hover {
    transform: translateY(-5px);
    box-shadow: 0 5px 15px var(--shadow-color);
}

.card-icon {
    font-size: 2.5rem;
    color: var(--primary-color);
    margin-bottom: 1rem;
}

.card h3 {
    margin-bottom: 1rem;
    color: var(--dark-color);
}

/* Accordion */
.accordion-item {
    margin-bottom: 1rem;
    border: 1px solid var(--border-color);
    border-radius: 6px;
    overflow: hidden;
}

.accordion-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1rem 1.5rem;
    background-color: rgba(52, 152, 219, 0.05);
    cursor: pointer;
    transition: background-color 0.3s;
}

.accordion-header:hover {
    background-color: rgba(52, 152, 219, 0.1);
}

.accordion-header h3 {
    margin: 0;
    color: var(--dark-color);
}

.accordion-icon {
    font-size: 1.5rem;
    color: var(--primary-color);
}

.accordion-content {
    padding: 0 1.5rem;
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.3s ease-out;
    background-color: white;
}

.accordion-content.active {
    max-height: 500px;
    padding: 1.5rem;
}

/* Two Column Layout */
.two-column {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 2rem;
}

@media (max-width: 768px) {
    .two-column {
        grid-template-columns: 1fr;
    }
}

/* Feature List */
.feature-list {
    list-style: none;
    padding: 0;
}

.feature-list li {
    display: flex;
    align-items: center;
    margin-bottom: 1rem;
    padding: 1rem;
    background-color: rgba(52, 152, 219, 0.05);
    border-radius: 6px;
}

.feature-list li i {
    color: var(--primary-color);
    font-size: 1.5rem;
    margin-right: 1rem;
}

/* Tabs */
.tabs {
    margin-top: 1.5rem;
}

.tab-headers {
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
    margin-bottom: 1rem;
}

.tab-btn {
    background-color: rgba(52, 152, 219, 0.1);
    border: none;
    padding: 0.75rem 1.5rem;
    border-radius: 4px;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s;
}

.tab-btn.active, .tab-btn:hover {
    background-color: var(--primary-color);
    color: white;
}

.tab-content {
    display: none;
    padding: 1.5rem;
    background-color: rgba(52, 152, 219, 0.05);
    border-radius: 6px;
}

.tab-content.active {
    display: block;
}

/* Quality Standards */
.quality-standards {
    display: grid;
    gap: 1.5rem;
}

.standard-item {
    display: flex;
    align-items: center;
    background-color: white;
    border-radius: 8px;
    padding: 1rem;
    box-shadow: 0 2px 10px var(--shadow-color);
}

.standard-icon {
    font-size: 2rem;
    color: var(--primary-color);
    margin-right: 1.5rem;
}

.standard-text h4 {
    margin-bottom: 0.5rem;
    color: var(--dark-color);
}

.standard-text p {
    margin-bottom: 0;
    color: var(--light-text-color);
}

/* Review Process */
.review-process {
    display: flex;
    flex-direction: column;
    gap: 2rem;
    margin-top: 1.5rem;
}

.process-step {
    display: flex;
    align-items: center;
    background-color: white;
    border-radius: 8px;
    padding: 1.5rem;
    box-shadow: 0 2px 10px var(--shadow-color);
}

.step-number {
    display: flex;
    justify-content: center;
    align-items: center;
    width: 3rem;
    height: 3rem;
    background-color: var(--primary-color);
    color: white;
    border-radius: 50%;
    font-size: 1.5rem;
    font-weight: 700;
    margin-right: 1.5rem;
}

.step-content h4 {
    margin-bottom: 0.5rem;
    color: var(--dark-color);
}

.step-content p {
    margin-bottom: 0;
    color: var(--light-text-color);
}

/* Timeline */
.timeline {
    position: relative;
    margin: 2rem 0;
    padding-left: 3rem;
}

.timeline::before {
    content: "";
    position: absolute;
    top: 0;
    bottom: 0;
    left: 15px;
    width: 2px;
    background-color: var(--primary-color);
}

.timeline-item {
    position: relative;
    margin-bottom: 2rem;
}

.timeline-dot {
    position: absolute;
    left: -3rem;
    width: 20px;
    height: 20px;
    background-color: var(--primary-color);
    border-radius: 50%;
    top: 5px;
}

.timeline-date {
    font-weight: 700;
    color: var(--primary-color);
    margin-bottom: 0.5rem;
}

.timeline-content {
    background-color: white;
    border-radius: 6px;
    padding: 1rem;
    box-shadow: 0 2px 10px var(--shadow-color);
}

/* Implementation Steps */
.implementation-steps {
    display: grid;
    gap: 1.5rem;
}

.step {
    display: flex;
    align-items: center;
    background-color: white;
    border-radius: 8px;
    padding: 1rem;
    box-shadow: 0 2px 10px var(--shadow-color);
}

.step-icon {
    display: flex;
    justify-content: center;
    align-items: center;
    width: 3rem;
    height: 3rem;
    background-color: rgba(52, 152, 219, 0.1);
    color: var(--primary-color);
    border-radius: 50%;
    font-size: 1.2rem;
    margin-right: 1.5rem;
}

.step-content h4 {
    margin-bottom: 0.5rem;
}

.step-content p {
    margin-bottom: 0;
    color: var(--light-text-color);
}

/* Highlight Cards */
.highlight-cards {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 2rem;
}

.highlight-card {
    background-color: white;
    border-radius: 8px;
    padding: 1.5rem;
    box-shadow: 0 2px 10px var(--shadow-color);
    text-align: center;
    transition: transform 0.3s, box-shadow 0.3s;
}

.highlight-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 5px 15px var(--shadow-color);
}

.highlight-icon {
    font-size: 2.5rem;
    color: var(--primary-color);
    margin-bottom: 1rem;
}

.highlight-card h3 {
    margin-bottom: 1rem;
    color: var(--dark-color);
}

/* Conclusion Section */
.conclusion-text {
    font-size: 1.1rem;
    line-height: 1.8;
    margin-bottom: 1.5rem;
    text-align: center;
    color: var(--dark-color);
}

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

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

.footer-section h3 {
    margin-bottom: 1.5rem;
    position: relative;
    padding-bottom: 0.5rem;
}

.footer-section h3::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 50px;
    height: 2px;
    background-color: var(--primary-color);
}

.footer-section p {
    margin-bottom: 0.75rem;
}

.footer-section i {
    margin-right: 0.5rem;
    color: var(--primary-color);
}

.copyright {
    text-align: center;
    padding-top: 2rem;
    border-top: 1px solid rgba(255, 255, 255, 0.1);
    color: rgba(255, 255, 255, 0.7);
}

/* Responsive Adjustments */
@media (max-width: 992px) {
    .header h1 {
        font-size: 2.4rem;
    }
    
    .header h2 {
        font-size: 1.5rem;
    }
    
    .section-title {
        font-size: 1.8rem;
    }
}

@media (max-width: 768px) {
    .header h1 {
        font-size: 2rem;
    }
    
    .header h2 {
        font-size: 1.3rem;
    }
    
    .section-title {
        font-size: 1.6rem;
    }
    
    .purpose-cards, .highlight-cards {
        grid-template-columns: 1fr;
    }
    
    .main-nav ul {
        justify-content: flex-start;
    }
}

@media (max-width: 576px) {
    .header {
        padding: 2rem 0;
    }
    
    .header h1 {
        font-size: 1.8rem;
    }
    
    .header h2 {
        font-size: 1.1rem;
    }
    
    .section-title {
        font-size: 1.4rem;
        padding: 1rem;
    }
    
    .section-content {
        padding: 1.5rem;
    }
    
    .card, .highlight-card {
        padding: 1rem;
    }
}