/* ========================================
   LAYOUT STYLES - Container, Header, Navigation
   ======================================== */

/* ========================================
   CONTAINER
   ======================================== */

.container {
    max-width: 1100px;
    margin: 0 auto;
    padding: var(--space-2xl) var(--space-lg);
    line-height: 1.7;
}

/* ========================================
   MAIN CONTENT AREA
   ======================================== */

#main-content {
    padding-top: 0;
}

.content-section {
    display: none;
    background: var(--bg-primary);
    padding: var(--space-2xl);
    border-radius: var(--radius-2xl);
    margin-bottom: var(--space-2xl);
    box-shadow: var(--shadow-md);
    border: 1px solid var(--border);
    min-height: 300px;
    scroll-margin-top: calc(var(--header-height) + 60px);
}

.content-section.active {
    display: block;
    animation: fadeInSlide 0.5s cubic-bezier(0.4, 0, 0.2, 1);
}

.content-section p,
.content-section li {
    line-height: 1.9;
    font-size: 1.02rem;
}

.content-section h1 { font-size: var(--font-3xl); margin-bottom: var(--space-md); }
.content-section h2 { font-size: var(--font-2xl); margin-bottom: var(--space-md); }
.content-section h3 { font-size: var(--font-xl); margin-bottom: var(--space-sm); }
.content-section h4 { font-size: var(--font-lg); margin-bottom: var(--space-sm); }

/* Learning Modules hero title shouldn't use global h2 underline */
#guide-heading {
    border-bottom: none;
    padding-bottom: 0;
}

#guide-heading::after {
    content: none;
}

@keyframes fadeInSlide {
    from {
        opacity: 0;
        transform: translateY(24px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* Home section special handling */
#home.content-section:not(.active) {
    display: none;
}

/* ========================================
   HEADER - STICKY NAVIGATION
   ======================================== */

header {
    position: sticky;
    top: 0;
    left: 0;
    right: 0;
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border-bottom: 1px solid #e2e8f0;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.05);
    z-index: var(--z-header);
    padding: 16px 0;
}

.header-inner {
    max-width: 1100px;
    margin: 0 auto;
    padding: 0 24px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: 32px;
}

.header-top {
    display: flex;
    align-items: center;
    gap: 1.5rem;
    flex: 1;
    min-width: 0;
}

.header-branding {
    display: flex;
    flex-direction: column;
    gap: 0.125rem;
    min-width: 0;
}

/* ========================================
   BREADCRUMB / UNIFIED NAVIGATION BAR
   ======================================== */

.breadcrumb-container {
    background: linear-gradient(135deg, var(--bg-secondary) 0%, var(--bg-primary) 100%);
    border-bottom: 2px solid var(--border);
    padding: 16px 0;
    position: sticky;
    top: var(--header-height);
    z-index: var(--z-sticky);
    transition: top 0.2s ease, all var(--transition-base);
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.04);
}

.breadcrumb-inner {
    max-width: 1100px;
    margin: 0 auto;
    padding: 0 24px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: 24px;
    flex-wrap: wrap;
}

/* Navigation context area */
.nav-context {
    display: flex;
    align-items: center;
    gap: 12px;
    flex-wrap: wrap;
}

.module-badge {
    background: linear-gradient(135deg, var(--primary), var(--secondary));
    color: white;
    padding: 8px 16px;
    border-radius: 20px;
    font-weight: 600;
    font-size: 0.9rem;
    box-shadow: 0 2px 6px rgba(99, 102, 241, 0.3);
    display: inline-flex;
    align-items: center;
    gap: 6px;
}

.step-indicator-text {
    color: var(--text-primary);
    font-weight: 500;
    font-size: 0.9rem;
    background: #eef2ff;
    padding: 8px 16px;
    border-radius: 20px;
    border: 2px solid #c7d2fe;
}

/* Progress dots area */
.nav-progress {
    display: flex;
    align-items: center;
}

.progress-dots {
    display: flex;
    align-items: center;
    gap: 12px;
    font-size: 0.85rem;
    color: var(--text-secondary);
}

.progress-dots .step-completed {
    color: var(--success);
    font-weight: 600;
}

.progress-dots .step-current {
    color: var(--primary);
    font-weight: 600;
}

.progress-dots .step-pending {
    color: var(--text-tertiary);
}

/* Hide unified nav on home page */
.breadcrumb-container.hidden {
    display: none;
}

/* Breadcrumb fallback for non-module pages */
.breadcrumb-item {
    color: #6b7280;
    text-decoration: none;
    transition: color var(--transition-base);
    font-size: 0.9rem;
}

.breadcrumb-item:hover:not(.active) {
    color: #4f46e5;
    cursor: pointer;
}

.breadcrumb-item.active {
    color: #6366f1;
    font-weight: 600;
}

.breadcrumb-separator {
    color: #d1d5db;
    user-select: none;
}

/* ========================================
   NAVIGATION
   ======================================== */

nav {
    display: flex;
    gap: var(--space-sm);
    flex-wrap: wrap;
}

/* Simplified Navigation */
.primary-nav {
    display: flex;
    align-items: center;
    gap: var(--space-sm);
    flex: 1;
    justify-content: center;
}

.nav-link {
    background: transparent;
    color: #64748b;
    border: 1px solid transparent;
    padding: var(--space-sm) var(--space-lg);
    min-height: 44px;
    min-width: 44px;
    border-radius: var(--radius-md);
    cursor: pointer;
    font-size: var(--font-sm);
    font-weight: 600;
    transition: all var(--transition-base);
    text-decoration: none;
    display: inline-flex;
    align-items: center;
    justify-content: center;
}

.nav-link:hover {
    background: #f1f5f9;
    color: #334155;
}

.nav-link:focus-visible {
    outline: 3px solid var(--secondary);
    outline-offset: 2px;
}

.nav-link.active {
    background: #eef2ff;
    color: #6366f1;
    border: 1px solid #c7d2fe;
}

.nav-actions {
    display: flex;
    gap: var(--space-sm);
    align-items: center;
}

#placement-btn {
    padding: var(--space-sm) var(--space-lg);
    font-size: var(--font-sm);
}

/* Main navigation - sticky */
#main-nav {
    position: sticky;
    top: 0;
    z-index: var(--z-sticky);
    background: var(--bg-primary);
    padding: var(--space-sm);
    margin: 0 calc(var(--space-sm) * -1) var(--space-xl);
    border-radius: var(--radius-xl);
    box-shadow: var(--shadow-sm);
    display: flex;
    flex-wrap: wrap;
    gap: var(--space-sm);
}

/* ========================================
   GRID LAYOUTS
   ======================================== */

.welcome-steps {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
    gap: var(--space-lg);
    margin-top: var(--space-xl);
}

.stats-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
    gap: var(--space-xl);
    margin: var(--space-xl) 0;
}

.model-diagram {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
    gap: 20px;
    justify-items: center;
    align-items: stretch;
    margin: var(--space-xl) 0;
}

/* ========================================
   VISUAL SEPARATORS
   ======================================== */

.section-divider {
    height: 2px;
    background: linear-gradient(90deg, transparent 0%, #e5e7eb 20%, #e5e7eb 80%, transparent 100%);
    margin: var(--space-3xl) 0;
    position: relative;
}

.section-divider::before {
    content: '';
    position: absolute;
    top: -1px;
    left: 50%;
    transform: translateX(-50%);
    width: 60px;
    height: 4px;
    background: linear-gradient(90deg, #6366f1, #8b5cf6);
    border-radius: 2px;
}

.section-divider-subtle {
    height: 1px;
    background: linear-gradient(90deg, transparent 0%, #f3f4f6 15%, #f3f4f6 85%, transparent 100%);
    margin: var(--space-2xl) 0;
}

/* ========================================
   RESPONSIVE LAYOUT
   ======================================== */

/* Tablet (768px and below) */
@media (max-width: 768px) {
    .container {
        padding: var(--space-lg);
    }

    header {
        padding: 0.5rem 1rem;
    }

    .header-inner {
        gap: 0.75rem;
        flex-direction: column;
        align-items: stretch;
    }

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

    .header-branding h1 {
        font-size: 1rem;
    }

    .header-branding .subtitle {
        font-size: 0.7rem;
    }

    .primary-nav {
        width: 100%;
        justify-content: center;
        gap: var(--space-xs);
    }

    .nav-link {
        padding: var(--space-xs) var(--space-sm);
        font-size: 0.7rem;
        border-radius: var(--radius-sm);
    }

    .nav-actions {
        width: 100%;
        justify-content: center;
    }

    #placement-btn {
        width: 100%;
        font-size: 0.75rem;
        padding: var(--space-sm) var(--space-md);
    }

    .breadcrumb-container {
        padding: 12px 0;
        top: var(--header-height);
    }

    .breadcrumb-inner {
        padding: 0 16px;
        flex-direction: column;
        gap: 12px;
    }

    .module-badge {
        font-size: 0.8rem;
        padding: 6px 12px;
    }

    .step-indicator-text {
        font-size: 0.8rem;
        padding: 6px 12px;
    }

    .progress-dots {
        font-size: 0.75rem;
        gap: 8px;
        flex-wrap: wrap;
    }

    .content-section {
        padding: var(--space-lg);
        box-shadow: var(--shadow-sm);
    }

    body {
        background: #f4f5fb;
    }

    nav {
        gap: var(--space-xs);
    }

    .stats-grid {
        grid-template-columns: repeat(2, 1fr);
        gap: var(--space-md);
    }

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

/* Tablets - Optimized 2-column layout */
@media (min-width: 768px) and (max-width: 1024px) {
    #learning-path {
        grid-template-columns: repeat(2, 1fr) !important;
        gap: 20px !important;
    }

    .header-inner {
        flex-direction: row;
        align-items: center;
    }

    .primary-nav {
        width: auto;
    }

    .nav-actions {
        width: auto;
    }

    .container {
        padding: var(--space-xl);
    }

    .content-section {
        padding: var(--space-xl);
    }
}

/* Mobile (480px and below) */
@media (max-width: 480px) {
    .container {
        padding: var(--space-sm);
    }

    header {
        padding: 0.5rem 0.75rem;
    }

    .header-branding h1 {
        font-size: 0.9rem;
        letter-spacing: -0.01em;
    }

    .header-branding .subtitle {
        font-size: 0.65rem;
    }

    nav {
        gap: 6px;
        margin-top: var(--space-lg);
    }

    .content-section {
        padding: var(--space-lg);
        border-radius: var(--radius-lg);
        margin-bottom: var(--space-lg);
    }

    .stats-grid {
        grid-template-columns: 1fr;
        gap: var(--space-md);
    }
}

/* Small phones - Extra compact */
@media (max-width: 374px) {
    .header-branding h1 {
        font-size: 0.9rem;
        line-height: 1.3;
    }

    .header-branding .subtitle {
        font-size: 0.65rem;
        display: none;
    }

    .primary-nav {
        gap: 4px;
    }

    .nav-link {
        padding: 6px 8px;
        font-size: 0.65rem;
    }

    .module-badge {
        font-size: 0.7rem;
        padding: 4px 10px;
    }

    .step-indicator-text {
        font-size: 0.7rem;
        padding: 4px 10px;
    }

    .content-section {
        padding: var(--space-md);
    }
}

/* Landscape mobile - Prevent overflow */
@media (max-width: 896px) and (orientation: landscape) {
    header {
        padding: 8px 16px;
    }

    .header-inner {
        gap: 12px;
    }

    .content-section {
        padding: var(--space-md);
    }
}

/* Landscape mobile optimization */
@media (max-width: 768px) and (orientation: landscape) {
    header {
        padding: 0.5rem 1rem;
    }

    .header-inner {
        gap: 0.5rem;
    }

    .content-section {
        padding: var(--space-md);
    }
}