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

.sidebar {
    width: var(--sidebar-width);
    background-color: var(--color-surface);
    border-right: 1px solid var(--color-border);
    padding: clamp(1rem, 3vw, 3rem);
    display: flex;
    flex-direction: column;
    flex-shrink: 0;
}

.brand-logo {
    font-size: clamp(1.25rem, 2vw, 1.5rem);
    font-weight: 700;
    color: var(--color-primary);
    letter-spacing: -0.02em;
    margin-bottom: clamp(1.5rem, 3vw, 2.5rem);
    display: block;
}

.nav-menu {
    display: flex;
    flex-direction: column;
    gap: 0.25rem;
}

.nav-btn {
    width: 100%;
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 0.75rem;
    border-radius: 0.5rem;
    font-size: clamp(0.875rem, 1vw, 1rem);
    font-weight: 500;
    color: var(--color-text-muted);
    transition: all 0.2s ease;
}

.nav-btn:hover {
    color: var(--hover-on-surface, #ffffff);
    background-color: var(--hover-surface, #182059);
}

.nav-btn.active {
    background-color: var(--color-hover);
    color: var(--color-primary);
}

.sub-menu {
    margin-left: 0.75rem;
    margin-top: 0.25rem;
    padding-left: 0.75rem;
    border-left: 1px solid var(--color-border);
    display: flex;
    flex-direction: column;
    gap: 0.125rem;
}

.sub-nav-btn {
    width: 100%;
    text-align: left;
    padding: 0.5rem 0.75rem;
    border-radius: 0.375rem;
    font-size: clamp(0.8rem, 0.9vw, 0.875rem);
    color: var(--color-text-muted);
    transition: all 0.2s;
}

.sub-nav-btn:hover {
    color: var(--hover-on-surface, #ffffff);
    background-color: var(--hover-surface, #182059);
}

.sub-nav-btn.active-sub {
    background-color: var(--color-hover);
    color: var(--color-accent);
    font-weight: 600;
}

.main-content {
    flex: 1;
    display: flex;
    flex-direction: column;
    min-width: 0;
}

.mobile-header {
    display: none;
    align-items: center;
    justify-content: space-between;
    padding: 1rem 1.5rem;
    background-color: var(--color-surface);
    border-bottom: 1px solid var(--color-border);
}

.content-wrapper {
    padding: var(--page-padding);
    max-width: 1400px;
    width: 100%;
    margin: 0 auto;
}

.page-title {
    font-size: 1.8rem;
    font-weight: 700;
    color: var(--color-primary);
    margin-bottom: 0.5rem;
    letter-spacing: -0.02em;
    line-height: 1.1;
}

.page-subtitle {
    font-size: 0.9rem;
    color: var(--color-text-muted);
    margin-bottom: clamp(1.5rem, 4vw, 2.5rem);
}

.subject-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(min(100%, 280px), 1fr));
    gap: clamp(0.75rem, 2vw, 1.5rem);
}

.subject-card {
    background-color: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: 0.75rem;
    padding: clamp(1rem, 2vw, 1.5rem);
    display: flex;
    flex-direction: column;
    transition: background-color var(--transition-normal), border-color var(--transition-normal), color var(--transition-normal);
}

.subject-card:hover {
    background-color: var(--hover-surface, #182059);
    border-color: var(--hover-surface, #182059);
}

.subject-card:hover .card-title,
.subject-card:hover .card-meta,
.subject-card:hover .card-number {
    color: var(--hover-on-surface, #ffffff);
}

.card-header {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    margin-bottom: clamp(0.75rem, 1.5vw, 1rem);
}

.book-icon {
    color: var(--color-text-muted);
    transition: color 0.3s ease;
}

.subject-card:hover .book-icon {
    color: var(--hover-on-surface, #ffffff);
}

.card-number {
    font-family: monospace;
    font-size: 0.75rem;
    color: var(--color-text-muted);
}

.card-title {
    font-size: 1rem;
    font-weight: 600;
    color: var(--color-primary);
    margin-bottom: 0.25rem;
    line-height: 1.3;
}

.card-meta {
    font-size: 0.8rem;
    color: var(--color-text-muted);
    margin-top: auto;
}

@media (max-width: 380px) {
    :root {
        --page-padding: 0.75rem;
    }

    .subject-card {
        padding: 0.875rem;
    }

    .card-header {
        margin-bottom: 0.5rem;
    }
}

@media (max-width: 240px) {
    .subject-grid {
        grid-template-columns: 1fr;
    }
}

@media (min-width: 1920px) {
    .subject-grid {
        grid-template-columns: repeat(auto-fill, minmax(350px, 1fr));
    }
}

.view-section {
    display: none;
}

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

@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(4px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.nclex-tabs {
    display: flex;
    gap: 0.25rem;
    margin-bottom: clamp(1.5rem, 3vw, 2.5rem);
    border-bottom: 1px solid var(--color-border);
    overflow-x: auto;
    scrollbar-width: none; 
    -webkit-overflow-scrolling: touch;
}

.nclex-tabs::-webkit-scrollbar {
    display: none;
}

.nclex-tab {
    position: relative;
    padding: 0.75rem clamp(1rem, 2vw, 1.25rem);
    font-size: clamp(0.875rem, 1vw, 1rem);
    font-weight: 500;
    white-space: nowrap;
    color: var(--color-text-muted);
    transition: color 0.2s ease;
    flex-shrink: 0;
}

.nclex-tab:hover {
    color: var(--hover-on-surface, #ffffff);
    background-color: var(--hover-surface, #182059);
    border-color: var(--hover-surface, #182059);
}

.nclex-tab.active {
    color: var(--color-text-main);
}

.nclex-tab.active::after {
    content: "";
    position: absolute;
    bottom: 0;
    left: 0;
    right: 0;
    height: 2px;
    background-color: var(--color-primary);
}

.nclex-pane {
    display: none;
}

.nclex-pane.active-pane {
    display: block;
}

.nclex-category-list {
    display: flex;
    flex-direction: column;
    gap: clamp(1rem, 2vw, 1.5rem);
}

.nclex-category-card {
    border: 1px solid var(--color-border);
    border-radius: 0.5rem;
    padding: clamp(1.25rem, 2vw, 1.5rem);
    background-color: var(--color-surface);
}

.nclex-category-title {
    font-size: 1.05rem;
    font-weight: 700;
    margin-bottom: 1rem;
    color: var(--color-text-main);
}

.nclex-links-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(min(100%, 280px), 1fr));
    gap: 0.5rem;
}

.nclex-link-item {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 0.75rem;
    border: 1px solid var(--color-border);
    border-radius: 0.375rem;
    font-size: 0.85rem;
    color: var(--color-primary);
    transition: border-color var(--transition-fast);
}

.nclex-link-item:hover {
    background-color: var(--hover-surface, #182059);
    border-color: var(--hover-surface, #182059);
    color: var(--hover-on-surface, #ffffff);
}

.nclex-link-item .icon {
    width: 14px;
    height: 14px;
    color: var(--color-text-muted);
    transition: color 0.2s;
}

.nclex-link-item:hover .icon {
    color: var(--hover-on-surface, #ffffff);
}

.nclex-builder-card {
    max-width: 32rem;
    border: 1px solid var(--color-border);
    border-radius: 0.5rem;
    padding: clamp(1.5rem, 3vw, 2rem);
    background-color: var(--color-surface);
}

.nclex-form-group {
    margin-bottom: 1.5rem;
}

.nclex-label {
    display: block;
    font-size: 0.875rem;
    font-weight: 500;
    margin-bottom: 0.5rem;
}

.nclex-input {
    width: 100%;
    padding: 0.75rem 1rem;
    border: 1px solid var(--color-border);
    border-radius: 0.375rem;
    background-color: var(--color-background);
    font-size: 0.875rem;
    color: var(--color-text-main);
}

.nclex-toggle-row {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 1rem;
    border: 1px solid var(--color-border);
    border-radius: 0.375rem;
    margin-bottom: 1.5rem;
}

.nclex-toggle-btn {
    width: 2.5rem;
    height: 1.5rem;
    border-radius: 9999px;
    background-color: var(--color-primary);
    position: relative;
    transition: background-color 0.2s;
}

.nclex-toggle-knob {
    width: 1rem;
    height: 1rem;
    border-radius: 50%;
    background-color: white;
    position: absolute;
    top: 0.25rem;
    left: 0.25rem;
    transform: translateX(1rem);
    transition: transform 0.2s;
}

.nclex-submit-btn {
    display: block;
    width: 100%;
    text-align: center;
    padding: 0.75rem 1.5rem;
    background-color: var(--color-primary);
    color: white;
    font-size: 0.875rem;
    font-weight: 500;
    border-radius: 0.375rem;
    transition: background-color 0.2s;
}

.nclex-submit-btn:hover {
    background-color: var(--hover-surface, #182059);
    color: var(--hover-on-surface, #ffffff);
}