/* 전체 스타일 */
:root {
    --primary-color: #0d47a1;
    --secondary-color: #1565c0;
    --accent-color: #2196f3;
    --light-color: #e3f2fd;
    --dark-color: #1a237e;
    --text-color: #333;
    --light-text: #fff;
    --background-color: #f9f9f9;
    --card-background: #fff;
    --border-radius: 8px;
    --box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
    --transition: all 0.3s ease;
}

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

body {
    font-family: 'Roboto', Arial, sans-serif;
    line-height: 1.6;
    color: var(--text-color);
    background-color: var(--background-color);
}

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

/* 헤더 스타일 */
header {
    background: linear-gradient(135deg, var(--dark-color), var(--primary-color));
    color: var(--light-text);
    padding: 3rem 0;
    text-align: center;
}

header h1 {
    font-size: 2.5rem;
    margin-bottom: 0.5rem;
    text-shadow: 0 2px 4px rgba(0, 0, 0, 0.2);
}

header .subtitle {
    font-size: 1.2rem;
    opacity: 0.9;
}

/* 네비게이션 스타일 */
nav {
    background-color: var(--primary-color);
    position: sticky;
    top: 0;
    z-index: 100;
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
}

nav ul {
    display: flex;
    list-style: none;
    justify-content: center;
    flex-wrap: wrap;
}

nav li {
    margin: 0;
}

nav a {
    color: var(--light-text);
    text-decoration: none;
    padding: 1rem 1.2rem;
    display: block;
    transition: var(--transition);
}

nav a:hover {
    background-color: var(--secondary-color);
}

/* 메인 콘텐츠 스타일 */
main {
    padding: 2rem 0;
}

section {
    margin-bottom: 3rem;
}

h2 {
    color: var(--primary-color);
    border-bottom: 2px solid var(--primary-color);
    padding-bottom: 0.5rem;
    margin-bottom: 1.5rem;
    font-size: 1.8rem;
}

h3 {
    color: var(--secondary-color);
    margin: 1rem 0 0.5rem;
    font-size: 1.4rem;
}

p {
    margin-bottom: 1rem;
}

/* 개요 섹션 스타일 */
.flex-container {
    display: flex;
    gap: 2rem;
    margin-top: 1.5rem;
}

.text-content {
    flex: 1;
}

.image-content {
    flex: 1;
    text-align: center;
}

.responsive-img {
    max-width: 100%;
    height: auto;
    border-radius: var(--border-radius);
    box-shadow: var(--box-shadow);
}

.caption {
    margin-top: 0.5rem;
    font-style: italic;
    color: #666;
    font-size: 0.9rem;
}

/* 작동 원리 섹션 스타일 */
.animation-container {
    text-align: center;
    margin-bottom: 2rem;
}

.principle-steps {
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
}

.step {
    display: flex;
    gap: 1rem;
    background-color: var(--card-background);
    border-radius: var(--border-radius);
    padding: 1.5rem;
    box-shadow: var(--box-shadow);
    transition: var(--transition);
}

.step:hover {
    transform: translateY(-5px);
    box-shadow: 0 8px 15px rgba(0, 0, 0, 0.1);
}

.step-number {
    background-color: var(--primary-color);
    color: var(--light-text);
    width: 40px;
    height: 40px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: bold;
    font-size: 1.2rem;
    flex-shrink: 0;
}

.step-content {
    flex: 1;
}

/* 구성 요소 섹션 스타일 */
.components-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(250px, 1fr));
    gap: 1.5rem;
    margin-top: 1.5rem;
}

.component-card {
    background-color: var(--card-background);
    border-radius: var(--border-radius);
    padding: 1.5rem;
    box-shadow: var(--box-shadow);
    transition: var(--transition);
    text-align: center;
}

.component-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 8px 15px rgba(0, 0, 0, 0.1);
}

.component-icon {
    font-size: 2rem;
    color: var(--primary-color);
    margin-bottom: 1rem;
}

/* 장점 섹션 스타일 */
.advantages-list, .disadvantages-list {
    display: flex;
    flex-direction: column;
    gap: 1rem;
}

.advantage-item, .disadvantage-item {
    display: flex;
    gap: 1rem;
    background-color: var(--card-background);
    border-radius: var(--border-radius);
    padding: 1.5rem;
    box-shadow: var(--box-shadow);
    transition: var(--transition);
}

.advantage-item:hover, .disadvantage-item:hover {
    transform: translateY(-3px);
    box-shadow: 0 6px 12px rgba(0, 0, 0, 0.1);
}

.advantage-icon, .disadvantage-icon {
    font-size: 1.5rem;
    color: var(--primary-color);
    flex-shrink: 0;
    width: 40px;
    text-align: center;
}

.advantage-content, .disadvantage-content {
    flex: 1;
}

/* 기술적 사양 섹션 스타일 */
.specs-table {
    margin-top: 1.5rem;
    overflow-x: auto;
}

table {
    width: 100%;
    border-collapse: collapse;
    margin-bottom: 1rem;
}

th, td {
    padding: 0.75rem;
    text-align: left;
    border-bottom: 1px solid #ddd;
}

th {
    background-color: var(--light-color);
    color: var(--primary-color);
    font-weight: bold;
}

tr:hover {
    background-color: rgba(0, 0, 0, 0.02);
}

/* 역사적 발전 섹션 스타일 */
.timeline {
    position: relative;
    max-width: 1200px;
    margin: 2rem auto;
}

.timeline::after {
    content: '';
    position: absolute;
    width: 6px;
    background-color: var(--primary-color);
    top: 0;
    bottom: 0;
    left: 50px;
    margin-left: -3px;
}

.timeline-item {
    padding: 10px 40px;
    position: relative;
    background-color: inherit;
    width: 100%;
    margin-bottom: 2rem;
}

.timeline-date {
    font-weight: bold;
    color: var(--primary-color);
    width: 100px;
    text-align: right;
    position: absolute;
    left: -60px;
}

.timeline-content {
    padding: 1.5rem;
    background-color: var(--card-background);
    position: relative;
    border-radius: var(--border-radius);
    box-shadow: var(--box-shadow);
    margin-left: 30px;
}

.timeline-content::after {
    content: '';
    position: absolute;
    width: 25px;
    height: 25px;
    right: 100%;
    top: 15px;
    background-color: var(--light-text);
    border: 4px solid var(--primary-color);
    border-radius: 50%;
    z-index: 1;
}

/* 비교 분석 섹션 스타일 */
.comparison-table {
    overflow-x: auto;
    margin-top: 1.5rem;
}

/* 결론 섹션 스타일 */
#conclusion p {
    margin-bottom: 1rem;
    line-height: 1.8;
}

/* 푸터 스타일 */
footer {
    background-color: var(--dark-color);
    color: var(--light-text);
    text-align: center;
    padding: 2rem 0;
    margin-top: 3rem;
}

footer p {
    margin-bottom: 0.5rem;
}

/* 반응형 디자인 */
@media (max-width: 992px) {
    .flex-container {
        flex-direction: column;
    }
    
    .timeline::after {
        left: 31px;
    }
    
    .timeline-date {
        width: auto;
        text-align: left;
        position: relative;
        left: 0;
        margin-bottom: 0.5rem;
    }
    
    .timeline-content {
        margin-left: 20px;
    }
}

@media (max-width: 768px) {
    nav ul {
        flex-direction: column;
    }
    
    nav a {
        padding: 0.75rem 1rem;
        text-align: center;
    }
    
    .components-grid {
        grid-template-columns: 1fr;
    }
    
    header h1 {
        font-size: 2rem;
    }
    
    .step {
        flex-direction: column;
    }
    
    .step-number {
        margin-bottom: 1rem;
    }
}

@media (max-width: 576px) {
    .advantage-item, .disadvantage-item {
        flex-direction: column;
    }
    
    .advantage-icon, .disadvantage-icon {
        margin-bottom: 1rem;
        width: 100%;
    }
}