/* Base Styles */
:root {
    --primary-color: #1a73e8;
    --secondary-color: #4285f4;
    --text-color: #202124;
    --text-secondary: #5f6368;
    --bg-color: #ffffff;
    --bg-secondary: #f8f9fa;
    --border-color: #dadce0;
    --accent-color: #34a853;
    --warning-color: #fbbc04;
    --error-color: #ea4335;
}

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

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
    background-color: var(--bg-color);
    color: var(--text-color);
    line-height: 1.6;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 24px;
}

/* Typography */
h1, h2, h3 {
    margin-bottom: 1rem;
    color: var(--text-color);
    font-weight: 600;
}

h1 {
    font-size: 3.5rem;
    text-align: center;
    margin-bottom: 1.5rem;
    line-height: 1.2;
}

h2 {
    font-size: 2.5rem;
    text-align: center;
    margin: 3rem 0 2rem;
    color: var(--primary-color);
}

h3 {
    font-size: 1.5rem;
    margin-bottom: 1rem;
}

p {
    color: var(--text-secondary);
    margin-bottom: 1rem;
}

/* Sections */
section {
    padding: 5rem 0;
    border-bottom: 1px solid var(--border-color);
}

/* Hero Section */
#hero {
    min-height: 80vh;
    display: flex;
    align-items: center;
    justify-content: center;
    text-align: center;
    background-color: var(--bg-secondary);
    padding: 4rem 0;
}

.hero-buttons {
    display: flex;
    gap: 1rem;
    justify-content: center;
    margin-top: 2rem;
}

.cta-button {
    display: inline-block;
    padding: 0.75rem 1.5rem;
    background-color: var(--primary-color);
    color: white;
    text-decoration: none;
    border-radius: 4px;
    font-weight: 500;
    transition: all 0.2s ease;
}

.cta-button.secondary {
    background-color: white;
    color: var(--primary-color);
    border: 1px solid var(--primary-color);
}

.cta-button:hover {
    background-color: var(--secondary-color);
    transform: translateY(-1px);
    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
}

.cta-button.secondary:hover {
    background-color: var(--bg-secondary);
}

/* Features Grid */
.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
    margin-top: 2rem;
}

.feature-card {
    background-color: var(--bg-secondary);
    padding: 2rem;
    border-radius: 8px;
    text-align: left;
    transition: transform 0.2s ease;
    border: 1px solid var(--border-color);
}

.feature-card:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 6px rgba(0,0,0,0.05);
}

.feature-card i {
    font-size: 1.5rem;
    color: var(--primary-color);
    margin-bottom: 1rem;
}

/* Architecture Diagram */
.architecture-diagram {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 1rem;
    margin: 2rem 0;
    max-width: 800px;
    margin: 2rem auto;
}

.layer {
    background-color: var(--bg-secondary);
    padding: 1rem 2rem;
    border-radius: 4px;
    width: 100%;
    text-align: center;
    border: 1px solid var(--border-color);
}

.connector {
    width: 2px;
    height: 20px;
    background-color: var(--border-color);
}

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

.math-card {
    background-color: var(--bg-secondary);
    padding: 2rem;
    border-radius: 8px;
    text-align: left;
    border: 1px solid var(--border-color);
}

.math-card i {
    font-size: 1.5rem;
    color: var(--primary-color);
    margin-bottom: 1rem;
}

/* Changelog */
.changelog-list {
    list-style: none;
    margin: 2rem 0;
}

.changelog-list li {
    margin-bottom: 0.75rem;
    padding-left: 1.5rem;
    position: relative;
    color: var(--text-secondary);
}

.changelog-list li::before {
    content: "•";
    color: var(--primary-color);
    position: absolute;
    left: 0;
}

/* Code Block */
.code-block {
    background-color: var(--bg-secondary);
    padding: 2rem;
    border-radius: 8px;
    margin: 2rem 0;
    overflow-x: auto;
    border: 1px solid var(--border-color);
}

.code-block pre {
    margin: 0;
    font-family: 'JetBrains Mono', monospace;
}

.code-block code {
    color: var(--text-color);
}

/* Requirements */
.requirements {
    margin: 2rem 0;
}

.requirements ul {
    list-style: none;
    margin-top: 1rem;
}

.requirements li {
    margin-bottom: 0.75rem;
    padding-left: 1.5rem;
    position: relative;
    color: var(--text-secondary);
}

.requirements li::before {
    content: "•";
    color: var(--primary-color);
    position: absolute;
    left: 0;
}

/* Warning */
.warning {
    background-color: var(--warning-color);
    color: var(--text-color);
    padding: 1rem;
    border-radius: 4px;
    margin: 2rem 0;
    display: flex;
    align-items: center;
    gap: 1rem;
}

/* Learning Goals */
.goals-list {
    list-style: none;
    margin: 2rem 0;
}

.goals-list li {
    margin-bottom: 0.75rem;
    padding-left: 1.5rem;
    position: relative;
    color: var(--text-secondary);
}

.goals-list li::before {
    content: "•";
    color: var(--primary-color);
    position: absolute;
    left: 0;
}

/* Subsystems Table */
.subsystems-table {
    margin: 2rem 0;
    overflow-x: auto;
}

table {
    width: 100%;
    border-collapse: collapse;
    background-color: var(--bg-secondary);
    border: 1px solid var(--border-color);
}

th, td {
    padding: 1rem;
    text-align: left;
    border: 1px solid var(--border-color);
}

th {
    background-color: var(--bg-secondary);
    color: var(--text-color);
    font-weight: 600;
}

/* Planned Features */
.planned-features {
    margin: 2rem 0;
}

.planned-features ul {
    list-style: none;
    margin-top: 1rem;
}

.planned-features li {
    margin-bottom: 0.75rem;
    padding-left: 1.5rem;
    position: relative;
    color: var(--text-secondary);
}

.planned-features li::before {
    content: "•";
    color: var(--primary-color);
    position: absolute;
    left: 0;
}

/* Footer */
footer {
    background-color: var(--bg-secondary);
    padding: 4rem 0;
    text-align: center;
    border-top: 1px solid var(--border-color);
}

.github-button {
    display: inline-block;
    padding: 0.75rem 1.5rem;
    background-color: var(--primary-color);
    color: white;
    text-decoration: none;
    border-radius: 4px;
    margin: 2rem 0;
    transition: all 0.2s ease;
}

.github-button:hover {
    background-color: var(--secondary-color);
    transform: translateY(-1px);
    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
}

.references {
    margin-top: 2rem;
}

.references ul {
    list-style: none;
    margin-top: 1rem;
}

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

.references a:hover {
    text-decoration: underline;
}

/* Responsive Design */
@media (max-width: 768px) {
    h1 {
        font-size: 2.5rem;
    }

    h2 {
        font-size: 2rem;
    }

    .hero-buttons {
        flex-direction: column;
        align-items: center;
    }

    .layer {
        width: 100%;
    }

    .features-grid,
    .math-grid {
        grid-template-columns: 1fr;
    }
}

/* Focus States */
a:focus,
button:focus {
    outline: 2px solid var(--primary-color);
    outline-offset: 2px;
}

/* Print Styles */
@media print {
    body {
        background-color: white;
        color: black;
    }

    .cta-button,
    .github-button {
        border: 1px solid black;
        color: black;
        text-decoration: none;
    }

    .code-block {
        border: 1px solid #ccc;
    }
}