/* Layout Structure */
#app {
    display: flex;
    flex-direction: column;
    min-height: 100vh;
    max-width: 1920px;
    margin: 0 auto;
}

/* Header */
#app-header {
    display: flex;
    align-items: center;
    gap: var(--spacing-lg);
    padding: 0 var(--spacing-xl);
    height: 56px;
    background-color: var(--bg-secondary);
    border-bottom: 1px solid var(--border-color);
    box-shadow: var(--shadow-xs);
    position: sticky;
    top: 0;
    z-index: 100;
    flex-shrink: 0;
}

.app-logo {
    font-size: var(--font-size-lg);
    font-weight: 800;
    color: var(--accent-primary);
    white-space: nowrap;
    letter-spacing: -0.5px;
    margin-right: var(--spacing-md);
}

#main-nav {
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
    margin-left: auto;
    flex-wrap: wrap;
}

/* Main content area */
#app-main {
    flex: 1;
    display: flex;
    flex-direction: column;
    padding: 0 var(--spacing-xl) var(--spacing-xl);
    overflow-y: auto;
}

/* Content */
#content {
    flex: 1;
    width: 100%;
}

/* Responsive */
@media (max-width: 1200px) {
    #app-header {
        padding: 0 var(--spacing-lg);
    }

    #app-main {
        padding: 0 var(--spacing-lg) var(--spacing-lg);
    }
}

@media (max-width: 900px) {
    #app-header {
        flex-wrap: wrap;
        height: auto;
        padding: var(--spacing-sm) var(--spacing-md);
        gap: var(--spacing-sm);
    }

    #main-nav {
        flex-wrap: wrap;
        margin-left: 0;
        width: 100%;
    }

    #app-main {
        padding: var(--spacing-md);
    }
}