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

:root {
    --primary-gradient: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    --secondary-gradient: linear-gradient(135deg, #f093fb 0%, #f5576c 100%);
    --accent-gradient: linear-gradient(135deg, #4facfe 0%, #00f2fe 100%);
    --success-color: #10b981;
    --text-primary: #1f2937;
    --text-secondary: #6b7280;
    --bg-primary: #ffffff;
    --bg-secondary: #f9fafb;
    --border-color: #e5e7eb;
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1);
}

body {
    font-family: 'Noto Sans KR', sans-serif;
    line-height: 1.6;
    color: var(--text-primary);
    background: var(--bg-secondary);
    overflow-x: hidden;
}

.container {
    display: flex;
    min-height: 100vh;
    max-width: 1400px;
    margin: 0 auto;
    background: var(--bg-primary);
    box-shadow: var(--shadow-lg);
}

/* Navigation Sidebar */
.nav-sidebar {
    width: 320px;
    background: var(--primary-gradient);
    padding: 2rem 1.5rem;
    position: sticky;
    top: 0;
    height: 100vh;
    overflow-y: auto;
    z-index: 100;
}

.nav-header {
    margin-bottom: 2rem;
    text-align: center;
}

.nav-title {
    color: white;
    font-size: 1.5rem;
    font-weight: 700;
    margin-bottom: 0.5rem;
    text-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
}

.nav-subtitle {
    color: rgba(255, 255, 255, 0.8);
    font-size: 0.9rem;
    font-weight: 400;
}

/* Overall Progress */
.overall-progress {
    margin-bottom: 2rem;
    padding: 1.5rem;
    background: rgba(255, 255, 255, 0.1);
    backdrop-filter: blur(10px);
    border-radius: 16px;
    border: 1px solid rgba(255, 255, 255, 0.2);
}

.progress-label {
    color: white;
    font-size: 0.9rem;
    font-weight: 500;
    margin-bottom: 0.75rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.progress-percentage {
    font-weight: 700;
    font-size: 1rem;
}

.progress-bar-container {
    width: 100%;
    height: 8px;
    background: rgba(255, 255, 255, 0.2);
    border-radius: 4px;
    overflow: hidden;
}

.progress-bar {
    height: 100%;
    background: linear-gradient(90deg, #10b981, #34d399);
    border-radius: 4px;
    transition: width 0.6s cubic-bezier(0.4, 0, 0.2, 1);
    width: 0%;
}

/* Navigation Menu */
.nav-menu {
    list-style: none;
    space-y: 0.5rem;
}

.nav-item {
    margin-bottom: 0.5rem;
}

.nav-link {
    display: flex;
    align-items: center;
    padding: 1rem 1.25rem;
    color: rgba(255, 255, 255, 0.8);
    text-decoration: none;
    border-radius: 12px;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    background: rgba(255, 255, 255, 0.05);
    border: 1px solid rgba(255, 255, 255, 0.1);
    cursor: pointer;
    position: relative;
    overflow: hidden;
}

.nav-link::before {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.1), transparent);
    transition: left 0.5s;
}

.nav-link:hover::before {
    left: 100%;
}

.nav-link:hover {
    background: rgba(255, 255, 255, 0.15);
    transform: translateX(4px);
    border-color: rgba(255, 255, 255, 0.3);
}

.nav-link.active {
    background: rgba(255, 255, 255, 0.2);
    color: white;
    font-weight: 600;
    border-color: rgba(255, 255, 255, 0.4);
    transform: translateX(8px);
}

.nav-link.completed {
    background: rgba(16, 185, 129, 0.2);
    border-color: rgba(16, 185, 129, 0.4);
}

.nav-link.completed::after {
    content: '✓';
    margin-left: auto;
    color: #10b981;
    font-weight: bold;
    font-size: 1.1rem;
}

.nav-step {
    font-size: 0.75rem;
    font-weight: 500;
    background: rgba(255, 255, 255, 0.2);
    padding: 0.25rem 0.5rem;
    border-radius: 6px;
    margin-right: 0.75rem;
    min-width: 24px;
    text-align: center;
}

.nav-text {
    font-size: 0.9rem;
    font-weight: 500;
}

/* Main Content */
.main-content {
    flex: 1;
    padding: 2rem;
    overflow-y: auto;
    height: 100vh;
}

.content-header {
    text-align: center;
    margin-bottom: 3rem;
    padding: 2rem;
    background: var(--primary-gradient);
    border-radius: 20px;
    color: white;
    position: relative;
    overflow: hidden;
}

.content-header::before {
    content: '';
    position: absolute;
    top: -50%;
    left: -50%;
    width: 200%;
    height: 200%;
    background: radial-gradient(circle, rgba(255, 255, 255, 0.1) 0%, transparent 70%);
    animation: rotate 20s linear infinite;
}

@keyframes rotate {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
}

.content-title {
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: 1rem;
    position: relative;
    z-index: 1;
}

.content-subtitle {
    font-size: 1.1rem;
    opacity: 0.9;
    position: relative;
    z-index: 1;
}

/* Roadmap Sections */
.roadmap-section {
    margin-bottom: 3rem;
    opacity: 0.7;
    transition: all 0.6s cubic-bezier(0.4, 0, 0.2, 1);
    transform: translateY(20px);
}

.roadmap-section.active {
    opacity: 1;
    transform: translateY(0);
}

.section-card {
    background: var(--bg-primary);
    border-radius: 20px;
    padding: 2.5rem;
    box-shadow: var(--shadow-md);
    border: 1px solid var(--border-color);
    position: relative;
    overflow: hidden;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

.section-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 4px;
    background: var(--primary-gradient);
    transform: scaleX(0);
    transition: transform 0.6s cubic-bezier(0.4, 0, 0.2, 1);
}

.roadmap-section.active .section-card::before {
    transform: scaleX(1);
}

.section-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
}

.section-header {
    display: flex;
    align-items: center;
    margin-bottom: 2rem;
}

.section-number {
    width: 48px;
    height: 48px;
    background: var(--primary-gradient);
    color: white;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 700;
    font-size: 1.2rem;
    margin-right: 1.5rem;
    box-shadow: var(--shadow-md);
}

.section-title {
    font-size: 1.8rem;
    font-weight: 700;
    color: var(--text-primary);
    margin-bottom: 0.5rem;
}

.section-duration {
    color: var(--text-secondary);
    font-size: 0.9rem;
    font-weight: 500;
}

.section-description {
    color: var(--text-secondary);
    font-size: 1rem;
    line-height: 1.7;
    margin-bottom: 2rem;
}

.topics-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 1.5rem;
    margin-bottom: 2rem;
}

.topic-card {
    background: var(--bg-secondary);
    border-radius: 12px;
    padding: 1.5rem;
    border: 1px solid var(--border-color);
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

.topic-card:hover {
    background: white;
    border-color: #667eea;
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
}

.topic-title {
    font-size: 1.1rem;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 0.75rem;
    display: flex;
    align-items: center;
}

.topic-icon {
    margin-right: 0.5rem;
    font-size: 1.2rem;
}

.topic-description {
    color: var(--text-secondary);
    font-size: 0.9rem;
    line-height: 1.6;
}

.section-resources {
    border-top: 1px solid var(--border-color);
    padding-top: 2rem;
}

.resources-title {
    font-size: 1.2rem;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 1rem;
    display: flex;
    align-items: center;
}

.resources-list {
    display: flex;
    flex-wrap: wrap;
    gap: 0.75rem;
}

.resource-tag {
    background: var(--primary-gradient);
    color: white;
    padding: 0.5rem 1rem;
    border-radius: 20px;
    font-size: 0.85rem;
    font-weight: 500;
    text-decoration: none;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

.resource-tag:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
    opacity: 0.9;
}

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

    .nav-sidebar {
        width: 100%;
        height: auto;
        position: relative;
        padding: 1.5rem;
    }

    .main-content {
        height: auto;
        padding: 1.5rem;
    }

    .content-title {
        font-size: 2rem;
    }

    .section-title {
        font-size: 1.5rem;
    }

    .topics-grid {
        grid-template-columns: 1fr;
    }
}

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

.roadmap-section.active {
    animation: fadeInUp 0.6s cubic-bezier(0.4, 0, 0.2, 1);
}