/* css/main.css */
* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

body {
    font-family: var(--font-family);
    background-color: var(--clr-bg-primary);
    color: var(--clr-text-main);
    line-height: 1.6;
    transition: background-color var(--transition-speed), color var(--transition-speed);
    overflow-x: hidden;
}

/* Accessibility */
.sr-only {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    white-space: nowrap;
    border-width: 0;
}

/* Layout */
.app-container {
    display: flex;
    height: 100vh;
    overflow: hidden;
}

.sidebar {
    width: 250px;
    background-color: var(--clr-bg-secondary);
    border-right: 1px solid var(--clr-border);
    display: flex;
    flex-direction: column;
    padding: 1.5rem;
    transition: transform 0.3s ease;
}

.brand {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    margin-bottom: 2rem;
}

.brand h1 {
    font-size: 1.25rem;
    font-weight: 700;
}

.sidebar nav {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
    flex: 1;
}

.nav-btn {
    background: transparent;
    border: none;
    color: var(--clr-text-muted);
    text-align: left;
    padding: 0.75rem 1rem;
    border-radius: var(--border-radius);
    cursor: pointer;
    font-size: 1rem;
    font-weight: 500;
    display: flex;
    align-items: center;
    gap: 0.75rem;
    transition: background-color var(--transition-speed), color var(--transition-speed);
}

.nav-btn:hover {
    background-color: rgba(15, 52, 96, 0.1);
    color: var(--clr-primary);
}

.nav-btn.active {
    background-color: var(--clr-primary);
    color: #ffffff;
}

.main-content {
    flex: 1;
    overflow-y: auto;
    padding: 2rem;
}

.view-section {
    display: none;
    animation: fadeIn 0.3s ease-in-out;
}

.view-section.active {
    display: block;
}

/* Typography */
h1, h2, h3, h4 {
    color: var(--clr-text-main);
}

.text-muted {
    color: var(--clr-text-muted);
    font-size: 0.875rem;
}

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(10px); }
    to { opacity: 1; transform: translateY(0); }
}

/* Responsive Design */
@media (max-width: 768px) {
    .app-container {
        flex-direction: column;
    }
    .sidebar {
        width: 100%;
        height: auto;
        flex-direction: row;
        justify-content: space-between;
        padding: 1rem;
        border-right: none;
        border-bottom: 1px solid var(--clr-border);
    }
    .sidebar nav {
        display: none; /* In production, trigger a hamburger menu here */
    }
}