:root {
    --bg-color: #f8fafc;
    --sidebar-bg: #ffffff;
    --text-primary: #0f172a;
    --text-secondary: #64748b;
    --accent-color: #3b82f6;
    --accent-hover: #2563eb;
    --border-color: #e2e8f0;
    --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.05);
    --shadow-md: 0 4px 6px -1px rgb(0 0 0 / 0.1), 0 2px 4px -2px rgb(0 0 0 / 0.1);
}

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

body {
    font-family: 'Inter', sans-serif;
    background-color: var(--bg-color);
    color: var(--text-primary);
    line-height: 1.5;
}

.layout {
    display: flex;
    height: 100vh;
    overflow: hidden;
}

/* Sidebar Styles */
.sidebar {
    width: 280px;
    background-color: var(--sidebar-bg);
    border-right: 1px solid var(--border-color);
    display: flex;
    flex-direction: column;
    z-index: 20;
    transition: transform 0.3s ease;
}

.sidebar-header {
    padding: 1.5rem;
    border-bottom: 1px solid var(--border-color);
}

.sidebar-header h2 {
    font-size: 1.25rem;
    font-weight: 600;
    color: var(--text-primary);
}

.sidebar-nav {
    flex: 1;
    overflow-y: auto;
    padding: 1rem 0;
}

.sidebar-nav ul {
    list-style: none;
}

.sidebar-nav li {
    margin: 0.25rem 1rem;
}

.sidebar-nav a {
    display: block;
    padding: 0.75rem 1rem;
    color: var(--text-secondary);
    text-decoration: none;
    border-radius: 0.5rem;
    transition: all 0.2s ease;
    font-size: 0.95rem;
    font-weight: 500;
}

.sidebar-nav a:hover {
    background-color: var(--bg-color);
    color: var(--text-primary);
}

.sidebar-nav a.active {
    background-color: #eff6ff;
    color: var(--accent-color);
    font-weight: 600;
}

.empty-state {
    padding: 1rem;
    color: var(--text-secondary);
    font-size: 0.9rem;
    text-align: center;
    font-style: italic;
}

/* Main Content Styles */
.main-content {
    flex: 1;
    display: flex;
    flex-direction: column;
    background-color: var(--bg-color);
    position: relative;
    height: 100%;
}

.newsletter-frame {
    width: 100%;
    height: 100%;
    border: none;
    background-color: #ffffff;
}

/* Welcome State */
.welcome-state {
    display: flex;
    align-items: center;
    justify-content: center;
    height: 100%;
    padding: 2rem;
}

.welcome-card {
    background: #ffffff;
    padding: 3rem;
    border-radius: 1rem;
    box-shadow: var(--shadow-md);
    text-align: center;
    max-width: 400px;
}

.welcome-card svg {
    width: 48px;
    height: 48px;
    color: var(--accent-color);
    margin-bottom: 1rem;
}

.welcome-card h1 {
    font-size: 1.5rem;
    margin-bottom: 0.5rem;
}

.welcome-card p {
    color: var(--text-secondary);
}

.welcome-card code {
    background-color: var(--bg-color);
    padding: 0.2rem 0.4rem;
    border-radius: 0.25rem;
    font-family: monospace;
    font-size: 0.9rem;
}

/* Mobile Menu Button */
.mobile-menu-btn {
    display: none;
    position: fixed;
    bottom: 1.5rem;
    right: 1.5rem;
    width: 3.5rem;
    height: 3.5rem;
    border-radius: 50%;
    background-color: var(--accent-color);
    color: white;
    border: none;
    box-shadow: var(--shadow-md);
    z-index: 30;
    cursor: pointer;
    align-items: center;
    justify-content: center;
    transition: background-color 0.2s;
}

.mobile-menu-btn:hover {
    background-color: var(--accent-hover);
}

.mobile-menu-btn svg {
    width: 24px;
    height: 24px;
}

/* Overlay */
.overlay {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background-color: rgba(0, 0, 0, 0.5);
    z-index: 10;
    opacity: 0;
    transition: opacity 0.3s ease;
}

/* Responsive Styles */
@media (max-width: 768px) {
    .sidebar {
        position: fixed;
        top: 0;
        bottom: 0;
        left: 0;
        transform: translateX(-100%);
    }

    .sidebar.open {
        transform: translateX(0);
    }

    .mobile-menu-btn {
        display: flex;
    }

    .overlay.active {
        display: block;
        opacity: 1;
    }
}