:root {
    --bg-primary: #1c1d25;
    --bg-secondary: #2e2f3e;
    --bg-card: #252632;
    --text-primary: #e4e5ea;
    --text-secondary: #a8a9b4;
    --accent: #d4a574;
    --accent-hover: #e8b989;
    --border: #3a3b4a;
    --success: #8b9d83;
    --success-bg: rgba(139, 157, 131, 0.1);
    --code-bg: #1a1b24;
}

/* Enable smooth scrolling globally */
html {
    scroll-behavior: smooth;
    scroll-padding-top: 80px; /* Offset for fixed headers or better positioning */
}

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

body {
    font-family: 'Crimson Pro', serif;
    background: var(--bg-primary);
    color: var(--text-primary);
    line-height: 1.7;
    font-size: 17px;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 40px 30px;
}

header {
    margin-bottom: 50px;
    border-bottom: 1px solid var(--border);
    padding-bottom: 30px;
}

.header-content {
    display: flex;
    align-items: center;
    gap: 20px;
    margin-bottom: 20px;
}

.logo {
    width: 80px;
    height: 80px;
    background: var(--bg-card);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-family: 'IBM Plex Mono', monospace;
    font-size: 2rem;
    color: var(--accent);
    border: 3px solid var(--accent);
}

h1 {
    font-size: 2.5rem;
    font-weight: 600;
    color: var(--text-primary);
    line-height: 1.2;
}

.subtitle {
    font-size: 1.2rem;
    color: var(--text-secondary);
    font-weight: 300;
    font-style: italic;
    margin-top: 8px;
}

.intro-box {
    background: var(--bg-secondary);
    padding: 30px;
    border-radius: 4px;
    border-left: 4px solid var(--accent);
    margin-bottom: 40px;
}

.intro-box p {
    color: var(--text-primary);
    margin-bottom: 12px;
}

.intro-box p:last-child {
    margin-bottom: 0;
}

.lesson-container {
    display: grid;
    grid-template-columns: 250px 1fr;
    gap: 40px;
    align-items: start;
}

.sidebar {
    position: sticky;
    top: 20px;
}

.lesson-contents {
    background: var(--bg-card);
    border-radius: 4px;
    padding: 20px;
    border: 1px solid var(--border);
}

.lesson-contents h3 {
    font-size: 1rem;
    color: var(--text-secondary);
    margin-bottom: 16px;
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.lesson-link {
    display: block;
    padding: 10px 12px;
    color: var(--text-secondary);
    text-decoration: none;
    border-radius: 4px;
    transition: all 0.3s ease;
    font-size: 0.95rem;
    margin-bottom: 4px;
}

.lesson-link:hover {
    background: var(--bg-secondary);
    color: var(--text-primary);
}

.lesson-link.active {
    background: var(--bg-secondary);
    color: var(--accent);
    border-left: 3px solid var(--accent);
    padding-left: 9px;
}

.main-content {
    min-height: 100vh;
}

.project-section {
    background: var(--bg-card);
    border-radius: 4px;
    padding: 40px;
    margin-bottom: 30px;
    border: 1px solid var(--border);
}

.project-header {
    display: flex;
    align-items: center;
    gap: 16px;
    margin-bottom: 24px;
    padding-bottom: 20px;
    border-bottom: 1px solid var(--border);
}

.project-icon {
    width: 60px;
    height: 60px;
    background: var(--bg-primary);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-family: 'IBM Plex Mono', monospace;
    font-size: 1.2rem;
    color: var(--accent);
    border: 2px solid var(--accent);
    flex-shrink: 0;
}

.project-title-group h2 {
    font-size: 1.8rem;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 6px;
}

.project-course {
    font-size: 0.95rem;
    color: var(--text-secondary);
    font-family: 'IBM Plex Mono', monospace;
}

.section-title {
    font-size: 1.3rem;
    font-weight: 600;
    color: var(--text-primary);
    margin-top: 32px;
    margin-bottom: 16px;
}

.section-content {
    color: var(--text-secondary);
    margin-bottom: 20px;
}

.section-content p {
    margin-bottom: 12px;
}

.assignment-section {
    background: var(--bg-secondary);
    padding: 28px;
    border-radius: 4px;
    margin-top: 32px;
}

.assignment-section h3 {
    font-size: 1.2rem;
    color: var(--text-primary);
    margin-bottom: 20px;
}

.assignment-list {
    color: var(--text-secondary);
}

.assignment-item {
    margin-bottom: 20px;
    padding-left: 28px;
    position: relative;
}

.assignment-item::before {
    content: attr(data-number);
    position: absolute;
    left: 0;
    color: var(--accent);
    font-weight: 600;
}

.tech-tags {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
    margin-top: 16px;
}

.tech-tag {
    background: var(--bg-primary);
    color: var(--accent);
    padding: 6px 14px;
    border-radius: 20px;
    font-size: 0.85rem;
    font-family: 'IBM Plex Mono', monospace;
    border: 1px solid var(--border);
}

.resources-box {
    background: var(--bg-secondary);
    padding: 24px;
    border-radius: 4px;
    margin-top: 24px;
    border-left: 4px solid var(--success);
}

.resources-box h4 {
    font-size: 1.1rem;
    color: var(--text-primary);
    margin-bottom: 12px;
}

.resource-link-item {
    display: block;
    color: var(--accent);
    text-decoration: none;
    padding: 8px 0;
    transition: all 0.2s ease;
}

.resource-link-item:hover {
    color: var(--accent-hover);
    padding-left: 8px;
}

.submission-section {
    background: var(--bg-primary);
    padding: 28px;
    border-radius: 4px;
    margin-top: 32px;
    border: 1px solid var(--border);
}

.submission-section h3 {
    font-size: 1.2rem;
    color: var(--text-primary);
    margin-bottom: 16px;
}

.submission-form {
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.form-group {
    display: flex;
    gap: 12px;
}

.form-input {
    flex: 1;
    background: var(--bg-card);
    border: 1px solid var(--border);
    color: var(--text-primary);
    padding: 12px 16px;
    border-radius: 4px;
    font-family: 'Crimson Pro', serif;
    font-size: 1rem;
    transition: all 0.2s ease;
}

.form-input:focus {
    outline: none;
    border-color: var(--accent);
    background: var(--bg-secondary);
}

.form-input::placeholder {
    color: var(--text-secondary);
}

.btn {
    background: var(--accent);
    color: var(--bg-primary);
    border: none;
    padding: 12px 24px;
    border-radius: 4px;
    font-family: 'IBM Plex Mono', monospace;
    font-size: 0.9rem;
    cursor: pointer;
    transition: all 0.2s ease;
    font-weight: 500;
}

.btn:hover {
    background: var(--accent-hover);
    transform: translateY(-1px);
}

.btn:active {
    transform: translateY(0);
}

.delete-btn {
    background: transparent;
    color: var(--text-secondary);
    border: 1px solid var(--border);
    padding: 12px 24px;
    border-radius: 4px;
    font-size: 0.9rem;
    cursor: pointer;
    transition: all 0.2s ease;
    font-family: 'IBM Plex Mono', monospace;
    font-weight: 500;
}

.delete-btn:hover {
    background: var(--bg-card);
    color: var(--text-primary);
    border-color: var(--text-secondary);
}

.view-repo-btn {
    background: var(--success);
    color: var(--bg-primary);
}

.view-repo-btn:hover {
    background: var(--success);
    opacity: 0.9;
}

code {
    background: var(--code-bg);
    padding: 3px 8px;
    border-radius: 3px;
    font-family: 'IBM Plex Mono', monospace;
    font-size: 0.9em;
    color: var(--accent);
    border: 1px solid var(--border);
}

.info-box {
    background: var(--bg-secondary);
    border-left: 4px solid var(--accent);
    padding: 20px 24px;
    border-radius: 4px;
    margin: 24px 0;
}

.info-box p {
    color: var(--text-secondary);
    margin-bottom: 8px;
}

.info-box p:last-child {
    margin-bottom: 0;
}

.info-box strong {
    color: var(--text-primary);
}

@keyframes fadeIn {
    from { opacity: 0; }
    to { opacity: 1; }
}

@keyframes slideIn {
    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.project-section {
    animation: slideIn 0.4s ease-out;
}

@media (max-width: 1024px) {
    .lesson-container {
        grid-template-columns: 1fr;
    }

    .sidebar {
        position: static;
    }

    .lesson-contents {
        margin-bottom: 30px;
    }
}

@media (max-width: 768px) {
    body {
        font-size: 16px;
    }

    .container {
        padding: 30px 20px;
    }

    h1 {
        font-size: 2rem;
    }

    .project-section {
        padding: 24px;
    }

    .form-group {
        flex-direction: column;
    }
}

.hidden {
    display: none;
}

.success-message {
    background: var(--success-bg);
    color: var(--success);
    padding: 12px 16px;
    border-radius: 4px;
    margin-top: 12px;
    font-size: 0.9rem;
    border-left: 3px solid var(--success);
}