/* App Shell */
.app {
    display: flex;
    flex-direction: column;
    min-height: 100dvh;
}

.app-header {
    position: sticky;
    top: 0;
    z-index: 100;
    height: var(--header-height);
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 0 var(--space-md);
    background: var(--color-surface);
    border-bottom: 1px solid var(--color-border);
}

.app-header__title {
    font-size: var(--font-size-lg);
    font-weight: var(--font-weight-bold);
    color: var(--color-primary);
}

.app-main {
    flex: 1;
    padding: var(--space-md);
    padding-bottom: calc(var(--nav-height) + var(--space-md));
    width: 100%;
    max-width: var(--max-width);
    margin: 0 auto;
}

/* Bottom Navigation */
.app-nav {
    position: fixed;
    bottom: 0;
    left: 0;
    right: 0;
    z-index: 100;
    height: var(--nav-height);
    display: flex;
    align-items: center;
    justify-content: space-around;
    background: var(--color-surface);
    border-top: 1px solid var(--color-border);
    padding-bottom: env(safe-area-inset-bottom);
}

.app-nav__item {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: var(--space-xs);
    padding: var(--space-sm);
    color: var(--color-text-muted);
    transition: color var(--transition);
}

.app-nav__item.is-active,
.app-nav__item:hover {
    color: var(--color-primary);
}

.app-nav__label {
    font-size: 0.625rem;
    font-weight: var(--font-weight-medium);
}

/* Page sections */
.page-section {
    margin-bottom: var(--space-xl);
}

.page-section__title {
    font-size: var(--font-size-lg);
    margin-bottom: var(--space-md);
}

/* Tablet landscape */
@media (min-width: 768px) and (orientation: landscape) {
    .app-main {
        max-width: var(--max-width-tablet);
        padding: var(--space-lg);
    }
}

/* Desktop */
@media (min-width: 1024px) {
    .app-nav {
        position: static;
        border-top: none;
        border-right: 1px solid var(--color-border);
        flex-direction: column;
        justify-content: flex-start;
        width: 80px;
        height: auto;
        padding: var(--space-lg) 0;
        gap: var(--space-sm);
    }

    .app {
        flex-direction: row;
    }

    .app-main {
        padding-bottom: var(--space-md);
        max-width: 600px;
    }

    .app-header {
        display: none;
    }
}