/* Reset and Base Styles */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Roboto', 'Helvetica', 'Arial', sans-serif;
    line-height: 1.6;
    color: #333;
    background-color: #ffffff;
}

/* Navigation */
.nav {
    background-color: #f8f9fa;
    border-bottom: 1px solid #e0e0e0;
    position: sticky;
    top: 0;
    z-index: 100;
}

.nav-container {
    max-width: 900px;
    margin: 0 auto;
    padding: 0 20px;
    display: flex;
    gap: 30px;
}

.nav-link {
    display: inline-block;
    padding: 16px 0;
    color: #666;
    text-decoration: none;
    font-size: 14px;
    font-weight: 500;
    border-bottom: 2px solid transparent;
    transition: color 0.2s, border-color 0.2s;
}

.nav-link:hover {
    color: #333;
}

.nav-link.active {
    color: #333;
    border-bottom-color: #333;
}

/* Container */
.container {
    max-width: 900px;
    margin: 0 auto;
    padding: 40px 20px;
}

/* Title Section */
.title-section {
    margin-bottom: 60px;
    padding-bottom: 40px;
    border-bottom: 1px solid #e0e0e0;
}

.title-section h1 {
    font-size: 42px;
    font-weight: 700;
    margin-bottom: 12px;
    color: #000;
    letter-spacing: -0.5px;
}

.subtitle {
    font-size: 20px;
    color: #666;
    margin-bottom: 8px;
    font-weight: 400;
}

.authors {
    font-size: 15px;
    color: #888;
    font-weight: 400;
}

/* Content Sections */
.content-section {
    margin-bottom: 50px;
}

.content-section h2 {
    font-size: 28px;
    font-weight: 600;
    margin-bottom: 20px;
    color: #000;
    letter-spacing: -0.3px;
}

.content-section p {
    font-size: 16px;
    line-height: 1.7;
    color: #333;
    margin-bottom: 16px;
}

/* Links Grid */
.links-grid {
    display: grid;
    grid-template-columns: 1fr;
    gap: 20px;
    margin-top: 20px;
}

.link-card {
    display: block;
    padding: 24px;
    background-color: #f8f9fa;
    border: 1px solid #e0e0e0;
    border-radius: 8px;
    text-decoration: none;
    transition: background-color 0.2s, border-color 0.2s;
}

.link-card:hover {
    background-color: #f0f0f0;
    border-color: #ccc;
}

.link-card h3 {
    font-size: 18px;
    font-weight: 600;
    color: #000;
    margin-bottom: 8px;
}

.link-card p {
    font-size: 14px;
    color: #666;
    margin: 0;
}

/* Goals List */
.goals-list {
    background-color: #f8f9fa;
    padding: 24px;
    border-radius: 8px;
    border: 1px solid #e0e0e0;
}

.goal-item strong {
    display: block;
    font-size: 16px;
    margin-bottom: 12px;
    color: #000;
}

.goal-item ul {
    list-style-position: inside;
    padding-left: 0;
}

.goal-item li {
    font-size: 15px;
    color: #333;
    margin-bottom: 8px;
    line-height: 1.6;
}

/* Schedule */
.schedule {
    display: flex;
    flex-direction: column;
    gap: 16px;
}

.schedule-item {
    display: block;
    padding: 20px;
    background-color: #f8f9fa;
    border-radius: 8px;
    border: 1px solid #e0e0e0;
}

.week {
    font-weight: 600;
    font-size: 15px;
    color: #000;
    min-width: 80px;
    flex-shrink: 0;
}

.task {
    font-size: 15px;
    color: #333;
    line-height: 1.6;
}

/* Footer */
footer {
    margin-top: 80px;
    padding: 30px 0;
    border-top: 1px solid #e0e0e0;
    background-color: #f8f9fa;
}

footer p {
    text-align: center;
    font-size: 14px;
    color: #888;
}

/* Responsive Design */
@media (max-width: 768px) {
    .title-section h1 {
        font-size: 32px;
    }
    
    .subtitle {
        font-size: 18px;
    }
    
    .content-section h2 {
        font-size: 24px;
    }
    
    .schedule-item {
        flex-direction: column;
        gap: 8px;
    }
    
    .week {
        min-width: auto;
    }
}