/* ============================
   Main Layout & Screens
   ============================ */

/* ---------- Layout ---------- */
.app-container {
    display: grid;
    grid-template-areas:
        "header header"
        "sidebar main";
    grid-template-columns: var(--sidebar-width) 1fr;
    grid-template-rows: var(--header-height) calc(100vh - var(--header-height));
    height: 100vh;
    overflow: hidden;
}

/* ---------- Header ---------- */
.header {
    grid-area: header;
    background-color: var(--color-white);
    border-bottom: 1px solid var(--color-gray-200);
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 0 var(--spacing-xl);
    box-shadow: var(--shadow-sm);
    z-index: 100;
    position: sticky;
    top: 0;
}

.header-left {
    display: flex;
    align-items: center;
    gap: var(--spacing-lg);
}

.logo {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    font-size: var(--font-size-xl);
    font-weight: var(--font-weight-bold);
    color: var(--color-primary);
}

.logo-icon {
    width: 36px;
    height: 36px;
    background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-accent) 100%);
    border-radius: var(--radius-md);
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--color-white);
    font-weight: var(--font-weight-bold);
}

.header-right {
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
}

.user-profile {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    padding: 8px 16px;
    border-radius: var(--radius-md);
    cursor: pointer;
    transition: background-color var(--transition-fast);
}

.user-profile:hover {
    background-color: var(--color-gray-100);
}

.user-avatar {
    width: 36px;
    height: 36px;
    border-radius: var(--radius-full);
    background: linear-gradient(135deg, var(--color-accent) 0%, var(--color-primary) 100%);
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--color-white);
    font-weight: var(--font-weight-semibold);
    font-size: var(--font-size-sm);
}

.user-name {
    font-size: var(--font-size-sm);
    font-weight: var(--font-weight-medium);
    color: var(--color-gray-800);
}

.logout-btn {
    padding: 8px 16px;
    background-color: var(--color-gray-100);
    border-radius: var(--radius-md);
    font-size: var(--font-size-sm);
    font-weight: var(--font-weight-medium);
    color: var(--color-gray-700);
    transition: all var(--transition-fast);
}

.logout-btn:hover {
    background-color: var(--color-gray-200);
}

/* ---------- Sidebar ---------- */
.sidebar {
    grid-area: sidebar;
    background-color: var(--color-white);
    border-right: 1px solid var(--color-gray-200);
    padding: var(--spacing-lg) 0;
    overflow-y: auto;
    overflow-x: hidden;
    height: 100%;
}

.nav-menu {
    list-style: none;
}

.nav-item {
    margin-bottom: var(--spacing-xs);
}

.nav-link {
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
    padding: 12px var(--spacing-xl);
    color: var(--color-gray-700);
    font-size: var(--font-size-sm);
    font-weight: var(--font-weight-medium);
    transition: all var(--transition-fast);
    position: relative;
}

.nav-link::before {
    content: '';
    position: absolute;
    left: 0;
    top: 0;
    bottom: 0;
    width: 4px;
    background-color: var(--color-accent);
    transform: scaleY(0);
    transition: transform var(--transition-base);
}

.nav-link:hover {
    background-color: var(--color-gray-100);
    color: var(--color-primary);
}

.nav-link.active {
    background-color: rgba(79, 163, 255, 0.1);
    color: var(--color-primary);
    font-weight: var(--font-weight-semibold);
}

.nav-link.active::before {
    transform: scaleY(1);
}

.nav-icon {
    font-size: var(--font-size-lg);
    width: 24px;
    text-align: center;
}

/* ---------- Main Content ---------- */
.main-content {
    grid-area: main;
    padding: var(--layout-gap);
    overflow-y: auto;
    overflow-x: hidden;
    max-width: var(--max-content-width);
    height: 100%;
}

.page-header {
    margin-bottom: var(--layout-gap);
}

.page-title {
    font-size: var(--font-size-3xl);
    font-weight: var(--font-weight-bold);
    color: var(--color-primary);
    margin-bottom: var(--spacing-xs);
}

.page-subtitle {
    font-size: var(--font-size-base);
    color: var(--color-gray-600);
}

.page-actions {
    display: flex;
    gap: var(--spacing-sm);
    margin-top: var(--spacing-md);
}

/* ---------- Login Screen ---------- */
.login-container {
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-accent) 100%);
    padding: var(--spacing-xl);
}

.login-card {
    background-color: var(--color-white);
    border-radius: var(--radius-xl);
    padding: var(--spacing-2xl);
    box-shadow: var(--shadow-xl);
    width: 100%;
    max-width: 420px;
}

.login-header {
    text-align: center;
    margin-bottom: var(--spacing-xl);
}

.login-logo {
    width: 64px;
    height: 64px;
    margin: 0 auto var(--spacing-md);
    background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-accent) 100%);
    border-radius: var(--radius-lg);
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--color-white);
    font-size: var(--font-size-2xl);
    font-weight: var(--font-weight-bold);
}

.login-title {
    font-size: var(--font-size-2xl);
    font-weight: var(--font-weight-bold);
    color: var(--color-primary);
    margin-bottom: var(--spacing-xs);
}

.login-subtitle {
    font-size: var(--font-size-sm);
    color: var(--color-gray-600);
}

.login-form {
    margin-bottom: var(--spacing-lg);
}

.login-footer {
    text-align: center;
    font-size: var(--font-size-xs);
    color: var(--color-gray-600);
}

/* ---------- Dashboard Grid ---------- */
.dashboard-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: var(--layout-gap);
    margin-bottom: var(--layout-gap);
}

/* ---------- Data Grid ---------- */
.data-grid {
    display: grid;
    gap: var(--layout-gap);
}

/* ---------- Attendance Screen ---------- */
.attendance-controls {
    background-color: var(--color-white);
    border-radius: var(--radius-lg);
    padding: var(--card-padding);
    margin-bottom: var(--layout-gap);
    box-shadow: var(--shadow-sm);
}

.attendance-controls-row {
    display: grid;
    grid-template-columns: 1fr 1fr auto;
    gap: var(--spacing-md);
    align-items: end;
}

.student-list {
    background-color: var(--color-white);
    border-radius: var(--radius-lg);
    padding: var(--card-padding);
    box-shadow: var(--shadow-sm);
}

.student-item {
    display: grid;
    grid-template-columns: 1fr auto;
    align-items: center;
    padding: var(--spacing-md);
    border-bottom: 1px solid var(--color-gray-200);
    transition: background-color var(--transition-fast);
}

.student-item:hover {
    background-color: var(--color-gray-100);
}

.student-item:last-child {
    border-bottom: none;
}

.student-info {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-xs);
}

.student-name {
    font-size: var(--font-size-base);
    font-weight: var(--font-weight-medium);
    color: var(--color-gray-800);
}

.student-group {
    font-size: var(--font-size-sm);
    color: var(--color-gray-600);
}

.student-status-buttons {
    display: flex;
    gap: var(--spacing-sm);
}

/* ---------- Toolbar ---------- */
.toolbar {
    background-color: var(--color-white);
    border-radius: var(--radius-lg);
    padding: var(--card-padding);
    margin-bottom: var(--layout-gap);
    box-shadow: var(--shadow-sm);
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: var(--spacing-md);
}

.toolbar-left,
.toolbar-right {
    display: flex;
    gap: var(--spacing-sm);
    align-items: center;
}

/* ---------- Responsive ---------- */
@media (max-width: 1024px) {
    .app-container {
        grid-template-columns: var(--sidebar-collapsed-width) 1fr;
    }

    .sidebar {
        padding: var(--spacing-md) 0;
    }

    .nav-link {
        justify-content: center;
        padding: 12px;
    }

    .nav-text {
        display: none;
    }

    .dashboard-grid {
        grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
    }
}

@media (max-width: 768px) {
    .app-container {
        grid-template-areas:
            "header"
            "main";
        grid-template-columns: 1fr;
        grid-template-rows: var(--header-height) 1fr;
    }

    .sidebar {
        position: fixed;
        left: -100%;
        top: var(--header-height);
        bottom: 0;
        width: var(--sidebar-width);
        z-index: 999;
        transition: left var(--transition-base);
        box-shadow: var(--shadow-lg);
    }

    .sidebar.active {
        left: 0;
    }

    .main-content {
        padding: var(--spacing-md);
    }

    .page-title {
        font-size: var(--font-size-2xl);
    }

    .dashboard-grid {
        grid-template-columns: 1fr;
    }

    .attendance-controls-row {
        grid-template-columns: 1fr;
    }

    .student-item {
        grid-template-columns: 1fr;
        gap: var(--spacing-md);
    }

    .student-status-buttons {
        justify-content: stretch;
    }

    .btn-status {
        flex: 1;
    }

    .toolbar {
        flex-direction: column;
        align-items: stretch;
    }

    .toolbar-left,
    .toolbar-right {
        flex-direction: column;
        width: 100%;
    }
}

@media (max-width: 480px) {
    .header {
        padding: 0 var(--spacing-md);
    }

    .user-name {
        display: none;
    }

    .login-card {
        padding: var(--spacing-xl);
    }

    .page-title {
        font-size: var(--font-size-xl);
    }
}

/* ---------- Utility Classes ---------- */
.hidden {
    display: none !important;
}

.text-center {
    text-align: center;
}

.text-right {
    text-align: right;
}

.mt-sm {
    margin-top: var(--spacing-sm);
}

.mt-md {
    margin-top: var(--spacing-md);
}

.mt-lg {
    margin-top: var(--spacing-lg);
}

.mb-sm {
    margin-bottom: var(--spacing-sm);
}

.mb-md {
    margin-bottom: var(--spacing-md);
}

.mb-lg {
    margin-bottom: var(--spacing-lg);
}

.gap-sm {
    gap: var(--spacing-sm);
}

.gap-md {
    gap: var(--spacing-md);
}

.gap-lg {
    gap: var(--spacing-lg);
}

.flex {
    display: flex;
}

.flex-column {
    flex-direction: column;
}

.items-center {
    align-items: center;
}

/* ============================
   Hamburger Menu Button
   ============================ */

.hamburger-btn {
    width: 40px;
    height: 40px;
    background: transparent;
    border: none;
    cursor: pointer;
    padding: 8px;
    display: flex;
    flex-direction: column;
    justify-content: center;
    gap: 6px;
    border-radius: var(--radius-md);
    transition: background-color var(--transition-fast);
}

.hamburger-btn:hover {
    background-color: var(--color-gray-100);
}

.hamburger-btn span {
    display: block;
    width: 24px;
    height: 3px;
    background-color: var(--color-gray-700);
    border-radius: 2px;
    transition: all var(--transition-base);
}

/* Animated hamburger when active */
.hamburger-btn.active span:nth-child(1) {
    transform: rotate(45deg) translate(6px, 6px);
}

.hamburger-btn.active span:nth-child(2) {
    opacity: 0;
}

.hamburger-btn.active span:nth-child(3) {
    transform: rotate(-45deg) translate(7px, -7px);
}

/* ============================
   Sidebar Collapsed State
   ============================ */

/* Adjust grid when sidebar is collapsed */
.app-container.sidebar-collapsed {
    grid-template-columns: 70px 1fr;
}

.app-container.sidebar-collapsed .sidebar {
    overflow: visible;
}

/* Hide nav text when collapsed */
.app-container.sidebar-collapsed .nav-text {
    display: none;
}

/* Center nav icons when collapsed */
.app-container.sidebar-collapsed .nav-link {
    justify-content: center;
    padding: 12px;
}

/* Tooltip on hover when collapsed */
.app-container.sidebar-collapsed .nav-link {
    position: relative;
}

.app-container.sidebar-collapsed .nav-link::after {
    content: attr(data-tooltip);
    position: absolute;
    left: 100%;
    top: 50%;
    transform: translateY(-50%);
    margin-left: 12px;
    padding: 8px 12px;
    background-color: var(--color-gray-900);
    color: var(--color-white);
    font-size: var(--font-size-sm);
    border-radius: var(--radius-md);
    white-space: nowrap;
    opacity: 0;
    pointer-events: none;
    transition: opacity var(--transition-fast);
    z-index: 1000;
}

.app-container.sidebar-collapsed .nav-link:hover::after {
    opacity: 1;
}

/* Smooth transition for sidebar width */
.sidebar {
    transition: all var(--transition-base);
}

.app-container {
    transition: grid-template-columns var(--transition-base);
}


.justify-between {
    justify-content: space-between;
}

.justify-center {
    justify-content: center;
}