/* ============================================
   LAYOUT SYSTEM
   ============================================ */

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

.app__sidebar {
    position: fixed;
    top: 0;
    left: 0;
    width: var(--sidebar-width);
    height: 100vh;
    background: var(--sidebar-bg);
    z-index: var(--z-sticky);
    transition: width var(--transition-base);
    overflow: hidden;
    display: flex;
    flex-direction: column;
}

.app__sidebar--collapsed {
    width: var(--sidebar-collapsed-width);
}

.app__main {
    flex: 1;
    margin-left: var(--sidebar-width);
    transition: margin-left var(--transition-base);
    display: flex;
    flex-direction: column;
    min-height: 100vh;
}

.app__sidebar--collapsed ~ .app__main {
    margin-left: var(--sidebar-collapsed-width);
}

.app__header {
    position: sticky;
    top: 0;
    height: var(--header-height);
    background: var(--color-surface);
    border-bottom: 1px solid var(--color-border);
    display: flex;
    align-items: center;
    padding: 0 var(--space-6);
    z-index: var(--z-sticky);
}

.app__content {
    flex: 1;
    padding: var(--space-6);
    overflow-y: auto;
    max-width: var(--max-content-width);
    width: 100%;
    margin: 0 auto;
}

/* --- Guest Layout (Login/Register) --- */
.guest {
    display: flex;
    min-height: 100vh;
    align-items: center;
    justify-content: center;
    background: var(--color-bg);
    padding: var(--space-4);
}

.guest__card {
    width: 100%;
    max-width: 440px;
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-xl);
    padding: var(--space-8);
    box-shadow: var(--shadow-lg);
}

.guest__logo {
    text-align: center;
    margin-bottom: var(--space-8);
}

.guest__logo-text {
    font-size: var(--text-2xl);
    font-weight: var(--font-black);
    color: var(--color-primary);
    letter-spacing: -0.03em;
    text-transform: uppercase;
}

.guest__title {
    font-size: var(--text-xl);
    font-weight: var(--font-bold);
    text-align: center;
    margin-bottom: var(--space-2);
}

.guest__subtitle {
    font-size: var(--text-sm);
    color: var(--color-text-secondary);
    text-align: center;
    margin-bottom: var(--space-6);
}

/* --- Page Header --- */
.page-header {
    display: flex;
    flex-direction: column;
    gap: var(--space-3);
    padding-bottom: var(--space-5);
    margin-bottom: var(--space-5);
    border-bottom: 1px solid var(--color-border);
}

.page-header__row {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: var(--space-4);
}

.page-header__title {
    font-size: var(--text-xl);
    font-weight: var(--font-black);
    text-transform: uppercase;
    letter-spacing: -0.02em;
    display: flex;
    align-items: center;
    gap: var(--space-2);
}

.page-header__actions {
    display: flex;
    align-items: center;
    gap: var(--space-2);
    flex-shrink: 0;
}

/* --- Grid System --- */
.grid {
    display: grid;
    gap: var(--space-4);
}

.grid--2 { grid-template-columns: repeat(2, 1fr); }
.grid--3 { grid-template-columns: repeat(3, 1fr); }
.grid--4 { grid-template-columns: repeat(4, 1fr); }

/* --- Mobile Drawer --- */
.app__drawer {
    display: none;
    position: fixed;
    bottom: 0;
    left: 0;
    right: 0;
    height: var(--drawer-height);
    background: var(--color-surface);
    border-top: 1px solid var(--color-border);
    z-index: var(--z-sticky);
    padding: 0 var(--space-2);
}

/* --- Responsive --- */
@media (max-width: 1024px) {
    .app__sidebar {
        transform: translateX(-100%);
        z-index: var(--z-overlay);
    }

    .app__sidebar--open {
        transform: translateX(0);
    }

    .app__main {
        margin-left: 0;
    }

    .app__sidebar--collapsed ~ .app__main {
        margin-left: 0;
    }

    .app__drawer {
        display: flex;
        align-items: center;
        justify-content: space-around;
    }

    .app__content {
        padding: var(--space-4);
        padding-bottom: calc(var(--drawer-height) + var(--space-4));
    }

    .page-header__row {
        flex-direction: column;
        align-items: flex-start;
    }

    .grid--2,
    .grid--3,
    .grid--4 {
        grid-template-columns: 1fr;
    }
}

@media (min-width: 640px) and (max-width: 1024px) {
    .grid--2 { grid-template-columns: repeat(2, 1fr); }
    .grid--3 { grid-template-columns: repeat(2, 1fr); }
    .grid--4 { grid-template-columns: repeat(2, 1fr); }
}

/* --- Overlay (mobile sidebar) --- */
.overlay {
    display: none;
    position: fixed;
    inset: 0;
    background: rgba(0, 0, 0, 0.5);
    z-index: calc(var(--z-overlay) - 1);
    backdrop-filter: blur(2px);
}

.overlay--active {
    display: block;
}