:root {
    --primary-color: #18edb3;
    --sidebar-width: 300px;
    --sidebar-collapsed-width: 80px;
    --header-height: 60px;
    --transition-speed: 0.3s;
    --bg-color: #fff;
    --text-color: #333;
    --sidebar-bg: #f8f9fa;
    --card-bg: #fff;
    --border-color: #e0e0e0;
    --hover-color: #f0f0f0;
    --active-color: #e0e0e0;
    --shadow-color: rgba(0, 0, 0, 0.1);
    --nav-button-bg: #f5f5f5;
}

[data-theme="dark"] {
    --text-color: #f0f0f0;
    --bg-color: #000000;
    --sidebar-bg: #111111;
    --card-bg: #1a1a1a;
    --border-color: #333333;
    --hover-color: #2a2a2a;
    --active-color: #333333;
    --shadow-color: rgba(0, 0, 0, 0.5);
    --nav-button-bg: #404040;
}

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

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

.container {
    display: flex;
    min-height: 100vh;
}

/* Theme Toggle */
.theme-toggle {
    position: fixed;
    top: 1rem;
    right: 1rem;
    background: none;
    border: none;
    cursor: pointer;
    font-size: 1.5rem;
    color: var(--text-color);
    z-index: 1001;
    padding: 0.5rem;
    border-radius: 50%;
    transition: background-color 0.3s ease;
}

.theme-toggle:hover {
    background-color: var(--hover-color);
}

/* Sidebar Styles */
.sidebar {
    width: 300px;
    background-color: var(--sidebar-bg);
    padding: 1rem;
    position: fixed;
    left: 0;
    top: 0;
    height: 100vh;
    overflow-y: auto;
    transition: width 0.3s ease;
    z-index: 1000;
}

.sidebar-header {
    display: flex;
    align-items: center;
    justify-content: center;
    margin-bottom: 1rem;
    padding-bottom: 1rem;
    border-bottom: 1px solid var(--border-color);
}

.logo-expanded {
    content: url('https://i.imgur.com/bFVYUtH.png');
    height: 40px;
    width: 120px;
    object-fit: contain;
    transition: opacity 0.3s ease;
    cursor: pointer;
    display: block;
}

[data-theme="dark"] .logo-expanded {
    content: url('https://i.imgur.com/aTKQMxl.png');
    height: 40px;
    width: 120px;
    object-fit: contain;
    display: block;
}

.logo-collapsed {
    content: url('https://i.imgur.com/aPz5jFB.png');
    height: 30px;
    width: 30px;
    object-fit: contain;
    display: none;
    cursor: pointer;
}

[data-theme="dark"] .logo-collapsed {
    content: url('https://i.imgur.com/LLHgjVa.png');
    height: 30px;
    width: 30px;
    object-fit: contain;
}

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

.nav-section:last-child {
    margin-bottom: 2rem;
}

.nav-section h3 {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    margin-bottom: 0.25rem;
    color: var(--text-color);
    padding: 0.25rem;
}

.nav-section .emoji {
    font-size: 1.2rem;
    width: 24px;
    text-align: center;
}

.nav-section .text {
    transition: opacity 0.3s ease;
}

.nav-section ul {
    list-style: none;
    padding: 0;
    margin: 0;
}

.nav-section li {
    margin-bottom: 0.25rem;
}

.nav-section a {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.25rem;
    color: var(--text-color);
    text-decoration: none;
    border-radius: 4px;
    transition: background-color 0.3s ease;
}

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

.nav-section a.active {
    background-color: var(--active-color);
    color: var(--text-color);
}

/* Main Content Styles */
.main-content {
    flex: 1;
    margin-left: var(--sidebar-width);
    transition: margin-left var(--transition-speed);
    padding: 2rem;
}

.sidebar.collapsed + .main-content {
    margin-left: var(--sidebar-collapsed-width);
}

.content-wrapper {
    max-width: 800px;
    margin: 0 auto;
}

section {
    margin-bottom: 3rem;
}

h1 {
    font-size: 2.5rem;
    margin-bottom: 1rem;
    color: var(--text-color);
}

h2 {
    font-size: 1.8rem;
    margin-bottom: 1rem;
    color: var(--text-color);
    border-bottom: 2px solid var(--primary-color);
    padding-bottom: 0.5rem;
}

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

/* Navigation Buttons */
.navigation-buttons {
    display: flex;
    justify-content: space-between;
    margin-top: 3rem;
    padding-top: 2rem;
    border-top: 1px solid var(--border-color);
}

.nav-button {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.8rem 1.5rem;
    background-color: var(--nav-button-bg);
    color: var(--text-color);
    text-decoration: none;
    border-radius: 4px;
    transition: all var(--transition-speed);
}

.nav-button:hover {
    background-color: var(--primary-color);
    color: var(--bg-color);
}

.nav-button.prev {
    margin-right: auto;
}

.nav-button.next {
    margin-left: auto;
}

/* Links */
a {
    color: var(--primary-color);
    text-decoration: none;
}

a:hover {
    text-decoration: underline;
}

/* Content Cards */
.content-card {
    background-color: var(--card-bg);
    border: 1px solid var(--border-color);
    border-radius: 8px;
    padding: 1.5rem;
    margin-bottom: 1.5rem;
}

.content-card h3 {
    color: var(--primary-color);
    margin-bottom: 1rem;
}

/* Responsive Design */
@media (max-width: 768px) {
    .sidebar {
        width: 80px;
    }

    .nav-section .text {
        display: none;
    }

    .logo-expanded {
        display: none;
    }

    .logo-collapsed {
        display: block;
    }

    .main-content {
        margin-left: 80px;
    }

    .nav-section h3 {
        justify-content: center;
    }

    .nav-section a {
        justify-content: center;
    }

    h1 {
        font-size: 2rem;
    }

    h2 {
        font-size: 1.5rem;
    }

    .navigation-buttons {
        flex-direction: column;
        gap: 1rem;
    }

    .nav-button {
        width: 100%;
        justify-content: center;
    }

    .theme-toggle {
        top: 0.5rem;
        right: 0.5rem;
    }
}