/* ==========================================================
   Portal Layout (Student + Admin)
   Sidebar, topbar, page wrapper, dashboard widgets
   ========================================================== */

/* ========== APP SHELL ========== */
.app-shell {
    min-height: 100vh;
    display: grid;
    grid-template-columns: var(--sidebar-width) 1fr;
    grid-template-rows: var(--header-height) 1fr;
    grid-template-areas:
        "sidebar topbar"
        "sidebar main";
    transition: grid-template-columns var(--transition-slow);
}
.app-shell.sidebar-collapsed { grid-template-columns: var(--sidebar-collapsed) 1fr; }

@media (max-width: 1024px) {
    .app-shell { grid-template-columns: 1fr; grid-template-areas: "topbar" "main"; }
    .app-shell .sidebar { transform: translateX(-100%); position: fixed; inset: 0 auto 0 0; z-index: 100; }
    .app-shell.sidebar-open .sidebar { transform: translateX(0); }
    .sidebar-overlay {
        position: fixed; inset: 0; background: rgba(0,0,0,.5);
        z-index: 99; opacity: 0; pointer-events: none;
        transition: opacity var(--transition-base);
    }
    .app-shell.sidebar-open .sidebar-overlay { opacity: 1; pointer-events: all; }
}

/* ========== SIDEBAR ========== */
.sidebar {
    grid-area: sidebar;
    background: var(--color-bg-elev);
    border-right: 1px solid var(--color-border);
    overflow-y: auto;
    width: var(--sidebar-width);
    display: flex; flex-direction: column;
}
.app-shell.sidebar-collapsed .sidebar { width: var(--sidebar-collapsed); }
.sidebar::-webkit-scrollbar { width: 6px; }

.sidebar-brand {
    padding: var(--space-5) var(--space-6);
    border-bottom: 1px solid var(--color-border);
    display: flex; align-items: center; gap: var(--space-3);
    height: var(--header-height);
}
.sidebar-brand .brand-logo {
    width: 36px; height: 36px;
    background: linear-gradient(135deg, var(--color-primary), var(--color-info));
    border-radius: var(--radius-md);
    display: flex; align-items: center; justify-content: center;
    color: white; font-weight: var(--weight-bold);
    flex-shrink: 0;
}
.sidebar-brand .brand-text {
    font-weight: var(--weight-bold);
    color: var(--color-text);
    font-size: var(--text-md);
    line-height: 1.2;
    white-space: nowrap; overflow: hidden;
}
.app-shell.sidebar-collapsed .brand-text { display: none; }

.sidebar-nav { padding: var(--space-4) 0; flex: 1; }
.nav-section { padding: var(--space-2) var(--space-3); }
.nav-section-title {
    padding: var(--space-2) var(--space-4);
    font-size: 11px;
    font-weight: var(--weight-bold);
    color: var(--color-text-dim);
    text-transform: uppercase;
    letter-spacing: 0.08em;
    margin-bottom: var(--space-1);
}
.app-shell.sidebar-collapsed .nav-section-title { display: none; }

.nav-item { position: relative; }
.nav-link {
    display: flex; align-items: center;
    padding: 10px 14px;
    gap: var(--space-3);
    border-radius: var(--radius-md);
    color: var(--color-text-muted);
    font-size: var(--text-sm);
    font-weight: var(--weight-medium);
    transition: all var(--transition-base);
    white-space: nowrap;
}
.nav-link:hover { background: var(--color-bg-hover); color: var(--color-text); }
.nav-link.active {
    background: var(--color-primary-soft);
    color: var(--color-primary-text);
    font-weight: var(--weight-semi);
}
.nav-link i, .nav-link svg {
    width: 18px; flex-shrink: 0; text-align: center;
    font-size: 16px;
}
.app-shell.sidebar-collapsed .nav-link span,
.app-shell.sidebar-collapsed .nav-link .nav-arrow { display: none; }

.nav-submenu { padding-left: var(--space-4); margin-top: var(--space-1); display: none; }
.nav-submenu.open { display: block; }
.nav-submenu .nav-link { padding: 8px 12px; font-size: var(--text-sm); }
.nav-arrow { margin-left: auto; transition: transform var(--transition-base); font-size: 11px; }
.nav-link.expanded .nav-arrow { transform: rotate(90deg); }

.sidebar-footer {
    padding: var(--space-4) var(--space-5);
    border-top: 1px solid var(--color-border);
    font-size: var(--text-xs);
    color: var(--color-text-dim);
    text-align: center;
}

/* ========== TOPBAR ========== */
.topbar {
    grid-area: topbar;
    background: var(--color-bg-elev);
    border-bottom: 1px solid var(--color-border);
    padding: 0 var(--space-6);
    display: flex; align-items: center; justify-content: space-between;
    gap: var(--space-4);
    position: sticky; top: 0; z-index: 50;
}
.topbar-left { display: flex; align-items: center; gap: var(--space-3); }
.topbar-toggle {
    width: 38px; height: 38px;
    display: inline-flex; align-items: center; justify-content: center;
    border-radius: var(--radius-md);
    color: var(--color-text-muted);
    transition: all var(--transition-base);
}
.topbar-toggle:hover { background: var(--color-bg-hover); color: var(--color-text); }

.topbar-title {
    font-size: var(--text-lg);
    font-weight: var(--weight-semi);
    color: var(--color-text);
}

.topbar-right { display: flex; align-items: center; gap: var(--space-2); }

.topbar-user {
    display: flex; align-items: center; gap: var(--space-3);
    padding: var(--space-1) var(--space-3);
    border-radius: var(--radius-md);
    cursor: pointer;
    transition: background var(--transition-base);
    position: relative;
}
.topbar-user:hover { background: var(--color-bg-hover); }
.user-avatar {
    width: 36px; height: 36px;
    border-radius: 50%;
    background: linear-gradient(135deg, var(--color-primary), var(--color-info));
    color: white;
    display: flex; align-items: center; justify-content: center;
    font-weight: var(--weight-semi);
    flex-shrink: 0;
}
.user-info { line-height: 1.2; }
.user-name { font-weight: var(--weight-semi); font-size: var(--text-sm); color: var(--color-text); }
.user-role { font-size: var(--text-xs); color: var(--color-text-muted); }

@media (max-width: 640px) { .user-info { display: none; } }

.dropdown-menu {
    position: absolute;
    right: 0; top: calc(100% + 4px);
    background: var(--color-bg-elev);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-md);
    box-shadow: var(--shadow-lg);
    min-width: 200px;
    padding: var(--space-2);
    z-index: 100;
    display: none;
}
.dropdown-menu.show { display: block; animation: fadeIn .15s ease; }
.dropdown-item {
    display: flex; align-items: center; gap: var(--space-2);
    padding: 8px 12px;
    border-radius: var(--radius-sm);
    color: var(--color-text);
    font-size: var(--text-sm);
    transition: background var(--transition-base);
}
.dropdown-item:hover { background: var(--color-bg-hover); }
.dropdown-divider { height: 1px; background: var(--color-divider); margin: var(--space-2) 0; }

/* ========== MAIN CONTENT ========== */
.main-content {
    grid-area: main;
    padding: var(--space-6);
    overflow-y: auto;
}
@media (max-width: 640px) { .main-content { padding: var(--space-4); } }

.page-header { margin-bottom: var(--space-6); }
.page-title { font-size: var(--text-2xl); font-weight: var(--weight-bold); margin-bottom: var(--space-1); }
.page-subtitle { color: var(--color-text-muted); font-size: var(--text-sm); }

.breadcrumbs {
    display: flex; align-items: center; gap: var(--space-2);
    font-size: var(--text-xs); color: var(--color-text-muted);
    margin-bottom: var(--space-3);
}
.breadcrumbs a { color: var(--color-text-muted); }
.breadcrumbs a:hover { color: var(--color-text); }
.breadcrumbs .sep::before { content: '/'; opacity: .5; }

/* ========== STAT CARDS ========== */
.stat-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
    gap: var(--space-4);
    margin-bottom: var(--space-6);
}
.stat-card {
    background: var(--color-bg-elev);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-lg);
    padding: var(--space-5);
    box-shadow: var(--shadow-xs);
    transition: transform var(--transition-base), box-shadow var(--transition-base);
    position: relative;
    overflow: hidden;
}
.stat-card:hover { transform: translateY(-2px); box-shadow: var(--shadow-md); }
.stat-card .stat-icon {
    position: absolute;
    right: -8px; top: -8px;
    font-size: 80px;
    opacity: .08;
    pointer-events: none;
    color: var(--stat-color, var(--color-primary));
}
.stat-card.primary { --stat-color: var(--color-primary); }
.stat-card.accent { --stat-color: var(--color-accent); }
.stat-card.warning { --stat-color: var(--color-warning); }
.stat-card.info { --stat-color: var(--color-info); }
.stat-card.danger { --stat-color: var(--color-danger); }

.stat-card .stat-icon-box {
    width: 44px; height: 44px;
    border-radius: var(--radius-md);
    background: var(--color-bg-elev-2);
    display: inline-flex; align-items: center; justify-content: center;
    color: var(--stat-color);
    margin-bottom: var(--space-3);
    font-size: 20px;
}
.stat-card .stat-label {
    font-size: var(--text-sm);
    color: var(--color-text-muted);
    margin-bottom: var(--space-1);
}
.stat-card .stat-value {
    font-size: var(--text-3xl);
    font-weight: var(--weight-bold);
    color: var(--color-text);
    line-height: 1.1;
}
.stat-card .stat-trend {
    margin-top: var(--space-2);
    font-size: var(--text-xs);
    color: var(--color-accent-text);
    display: inline-flex; align-items: center; gap: var(--space-1);
}
.stat-card .stat-trend.down { color: var(--color-danger-text); }

/* ========== LOGIN PAGES ========== */
.auth-page {
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: var(--space-6);
    background:
        radial-gradient(ellipse 80% 50% at 50% -20%, var(--color-primary-soft), transparent),
        radial-gradient(ellipse 60% 50% at 80% 100%, var(--color-info-soft), transparent),
        var(--color-bg);
    position: relative;
}
.auth-card {
    width: 100%;
    max-width: 440px;
    background: var(--color-bg-elev);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-2xl);
    box-shadow: var(--shadow-lg);
    padding: var(--space-8);
    animation: fadeIn .35s ease;
}
.auth-header { text-align: center; margin-bottom: var(--space-6); }
.auth-logo {
    width: 60px; height: 60px;
    background: linear-gradient(135deg, var(--color-primary), var(--color-info));
    border-radius: var(--radius-lg);
    display: inline-flex; align-items: center; justify-content: center;
    color: white; font-size: 28px;
    margin-bottom: var(--space-4);
    box-shadow: var(--shadow-md);
}
.auth-title { font-size: var(--text-2xl); font-weight: var(--weight-bold); margin-bottom: var(--space-1); }
.auth-subtitle { color: var(--color-text-muted); font-size: var(--text-sm); }

.auth-divider {
    text-align: center;
    margin: var(--space-5) 0;
    font-size: var(--text-xs);
    color: var(--color-text-dim);
    position: relative;
}
.auth-divider::before, .auth-divider::after {
    content: ''; position: absolute; top: 50%;
    width: calc(50% - 30px);
    height: 1px; background: var(--color-divider);
}
.auth-divider::before { left: 0; }
.auth-divider::after { right: 0; }

.auth-footer {
    text-align: center;
    margin-top: var(--space-6);
    padding-top: var(--space-5);
    border-top: 1px solid var(--color-divider);
    font-size: var(--text-sm);
    color: var(--color-text-muted);
}
.auth-footer a { font-weight: var(--weight-semi); color: var(--color-primary); }

.auth-page .theme-toggle-floating {
    position: absolute;
    top: var(--space-5); right: var(--space-5);
}

/* ========== COURSE CARDS (Student) ========== */
.courses-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: var(--space-5);
}
.course-card {
    background: var(--color-bg-elev);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-lg);
    overflow: hidden;
    transition: all var(--transition-base);
    position: relative;
    display: flex; flex-direction: column;
}
.course-card:hover { transform: translateY(-3px); box-shadow: var(--shadow-md); border-color: var(--color-border-strong); }
.course-card-cover {
    height: 130px;
    background: linear-gradient(135deg, var(--color-primary), var(--color-info));
    position: relative;
    display: flex; align-items: center; justify-content: center;
    color: white;
}
.course-card-cover .course-icon-bg { font-size: 48px; opacity: .85; }
.course-card-cover img { width: 100%; height: 100%; object-fit: cover; }

.course-card-body { padding: var(--space-5); flex: 1; display: flex; flex-direction: column; gap: var(--space-3); }
.course-title { font-size: var(--text-md); font-weight: var(--weight-bold); color: var(--color-text); line-height: var(--leading-snug); }
.course-meta { display: flex; align-items: center; gap: var(--space-3); font-size: var(--text-xs); color: var(--color-text-muted); }
.course-meta i { margin-right: 4px; }
.course-price { font-size: var(--text-xl); font-weight: var(--weight-bold); color: var(--color-primary); }

.course-card-footer {
    padding: var(--space-3) var(--space-5);
    border-top: 1px solid var(--color-divider);
    display: flex; align-items: center; justify-content: space-between;
    background: var(--color-bg-elev-2);
}

.course-card.paid .course-card-cover { background: linear-gradient(135deg, var(--color-accent), #16a34a); }
.course-card.pending .course-card-cover { background: linear-gradient(135deg, var(--color-warning), #d97706); }
.course-card.blocked .course-card-cover { background: linear-gradient(135deg, var(--color-info), #4f46e5); }

.course-status-badge {
    position: absolute;
    top: var(--space-3); right: var(--space-3);
    padding: 4px 10px;
    background: rgba(255,255,255,.95);
    color: var(--color-text);
    font-size: var(--text-xs);
    font-weight: var(--weight-semi);
    border-radius: var(--radius-full);
    backdrop-filter: blur(4px);
    display: inline-flex; align-items: center; gap: 4px;
}

/* ========== LESSON VIEWER ========== */
.lesson-viewer {
    background: var(--color-bg-elev);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-lg);
    overflow: hidden;
}
.lesson-meta-bar {
    display: flex; flex-wrap: wrap; align-items: center; justify-content: space-between;
    gap: var(--space-3);
    padding: var(--space-4) var(--space-5);
    background: var(--color-bg-elev-2);
    border-bottom: 1px solid var(--color-border);
    font-size: var(--text-sm);
}
.lesson-meta-info { display: flex; flex-wrap: wrap; gap: var(--space-4); align-items: center; }
.lesson-meta-info span { display: inline-flex; align-items: center; gap: var(--space-1); color: var(--color-text-muted); }
.lesson-meta-info span i { color: var(--color-primary); }
.lesson-meta-info strong { color: var(--color-text); }

.lesson-content { min-height: 70vh; background: #000; }
.lesson-content iframe, .lesson-content video {
    width: 100%; height: 100%; min-height: 70vh;
    border: 0;
}

.lesson-progress-bar-wrap { padding: var(--space-3) var(--space-5); background: var(--color-bg-elev); border-top: 1px solid var(--color-border); }
.lesson-progress-bar { height: 6px; background: var(--color-bg-elev-2); border-radius: var(--radius-full); overflow: hidden; }
.lesson-progress-bar-fill { height: 100%; background: linear-gradient(90deg, var(--color-primary), var(--color-info)); transition: width .3s ease; border-radius: var(--radius-full); }

/* ========== EXAM ========== */
.exam-wrapper {
    max-width: 800px;
    margin: 0 auto;
}
.exam-header {
    background: linear-gradient(135deg, var(--color-bg-elev), var(--color-bg-elev-2));
    border: 1px solid var(--color-border);
    border-radius: var(--radius-lg);
    padding: var(--space-5) var(--space-6);
    margin-bottom: var(--space-5);
    display: flex; align-items: center; justify-content: space-between; flex-wrap: wrap; gap: var(--space-3);
}
.exam-header h2 { font-size: var(--text-lg); margin-bottom: var(--space-1); }
.exam-header .exam-meta { font-size: var(--text-sm); color: var(--color-text-muted); }

.exam-timer {
    display: inline-flex; align-items: center; gap: var(--space-2);
    padding: var(--space-2) var(--space-4);
    background: var(--color-danger-soft);
    color: var(--color-danger-text);
    border-radius: var(--radius-md);
    font-weight: var(--weight-bold);
    font-size: var(--text-md);
    font-variant-numeric: tabular-nums;
}
.exam-timer.warning { background: var(--color-warning-soft); color: var(--color-warning-text); }
.exam-timer.urgent { background: var(--color-danger); color: white; animation: pulse 1s infinite; }

.exam-question {
    background: var(--color-bg-elev);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-lg);
    padding: var(--space-6);
    box-shadow: var(--shadow-sm);
}
.exam-question-num {
    display: inline-block;
    padding: 4px 10px;
    background: var(--color-primary-soft);
    color: var(--color-primary-text);
    font-size: var(--text-xs);
    font-weight: var(--weight-semi);
    border-radius: var(--radius-full);
    margin-bottom: var(--space-3);
}
.exam-question-text {
    font-size: var(--text-lg);
    font-weight: var(--weight-semi);
    line-height: var(--leading-snug);
    margin-bottom: var(--space-5);
    color: var(--color-text);
}

.exam-options { display: flex; flex-direction: column; gap: var(--space-3); }
.exam-option {
    display: flex; align-items: center; gap: var(--space-3);
    padding: var(--space-4) var(--space-5);
    border: 2px solid var(--color-border);
    border-radius: var(--radius-md);
    cursor: pointer;
    transition: all var(--transition-base);
    background: var(--color-bg-elev);
}
.exam-option:hover { border-color: var(--color-primary); background: var(--color-primary-soft); }
.exam-option.selected { border-color: var(--color-primary); background: var(--color-primary-soft); }
.exam-option input { accent-color: var(--color-primary); width: 18px; height: 18px; flex-shrink: 0; }
.exam-option span { font-size: var(--text-md); color: var(--color-text); }

.exam-actions {
    display: flex; justify-content: space-between; align-items: center;
    margin-top: var(--space-5);
    padding-top: var(--space-5);
    border-top: 1px solid var(--color-divider);
}

/* ========== EMPTY STATES ========== */
.empty-state {
    text-align: center;
    padding: var(--space-12) var(--space-6);
    color: var(--color-text-muted);
}
.empty-state-icon {
    font-size: 64px;
    color: var(--color-text-dim);
    margin-bottom: var(--space-4);
}
.empty-state h3 { color: var(--color-text); margin-bottom: var(--space-2); }
.empty-state p { font-size: var(--text-sm); max-width: 360px; margin: 0 auto var(--space-4); }

/* ========== MODAL ========== */
.modal-backdrop {
    position: fixed; inset: 0;
    background: rgba(15, 23, 42, .55);
    backdrop-filter: blur(4px);
    display: none; align-items: center; justify-content: center;
    z-index: 1000;
    padding: var(--space-5);
}
.modal-backdrop.show { display: flex; animation: fadeIn .2s; }
.modal {
    background: var(--color-bg-elev);
    border-radius: var(--radius-xl);
    box-shadow: var(--shadow-xl);
    width: 100%;
    max-width: 540px;
    max-height: 90vh;
    overflow-y: auto;
    animation: fadeIn .3s ease;
}
.modal-header {
    padding: var(--space-5) var(--space-6);
    border-bottom: 1px solid var(--color-divider);
    display: flex; justify-content: space-between; align-items: center;
}
.modal-header h3 { font-size: var(--text-lg); margin: 0; }
.modal-close { color: var(--color-text-muted); font-size: 22px; line-height: 1; padding: 4px 8px; border-radius: var(--radius-sm); }
.modal-close:hover { background: var(--color-bg-hover); color: var(--color-text); }
.modal-body { padding: var(--space-6); }
.modal-footer { padding: var(--space-4) var(--space-6); border-top: 1px solid var(--color-divider); display: flex; gap: var(--space-3); justify-content: flex-end; }