/* ========================================
   CSS Variables (Design System)
   ======================================== */
:root {
    --color-aws-dark: #232F3E;
    --color-aws-orange: #dc7600;
    --color-aws-orange-original: #FF9900;
    --color-aws-orange-hover: #EC7211;
    --color-text-primary: #374151;
    --color-text-secondary: #6B7280;
    --color-text-white: #FFFFFF;
    --color-bg-light: #F9FAFB;
    --color-bg-white: #FFFFFF;
    --color-border: #909296;
    --color-border-light: #E5E7EB;
    --color-success: #10B981;
    --color-warning: #F59E0B;
    --color-error: #EF4444;
    --color-info: #3B82F6;
    --color-category-networking: #74b9ff;
    --spacing-xs: 5px;
    --spacing-sm: 10px;
    --spacing-md: 15px;
    --spacing-base: 20px;
    --spacing-lg: 25px;
    --spacing-xl: 30px;
    --spacing-2xl: 40px;
    --spacing-3xl: 60px;
    --radius-sm: 6px;
    --radius-md: 8px;
    --radius-base: 10px;
    --radius-lg: 15px;
    --radius-xl: 20px;
    --shadow-sm: 0 2px 4px rgba(0,0,0,0.1);
    --shadow-md: 0 4px 12px rgba(0,0,0,0.1);
    --shadow-lg: 0 10px 40px rgba(0,0,0,0.15);
    --transition-base: 0.3s ease;
    --font-weight-medium: 500;
    --font-weight-semibold: 600;
    --font-weight-bold: 700;
}

/* ========================================
   Hero Section
   ======================================== */
.hero {
    background: linear-gradient(135deg, #1a1a2e 0%, #16213e 50%, #0f3460 100%);
    border-radius: var(--radius-xl);
    padding: var(--spacing-2xl) var(--spacing-xl);
    margin-bottom: var(--spacing-2xl);
    color: var(--color-text-white);
    position: relative;
    overflow: hidden;
}
.hero::before {
    content: '';
    position: absolute;
    top: -50%;
    right: -20%;
    width: 400px;
    height: 400px;
    background: radial-gradient(circle, rgba(255,153,0,0.15) 0%, transparent 70%);
    border-radius: 50%;
}
.hero-badge {
    display: inline-block;
    background: rgba(255,153,0,0.2);
    border: 1px solid rgba(255,153,0,0.4);
    color: var(--color-aws-orange-original);
    padding: 6px 16px;
    border-radius: 20px;
    font-size: 0.8em;
    font-weight: var(--font-weight-semibold);
    margin-bottom: var(--spacing-md);
}
.hero h1 {
    font-size: 1.8em;
    font-weight: var(--font-weight-bold);
    margin-bottom: var(--spacing-sm);
    line-height: 1.3;
    color: var(--color-text-white);
}
.hero-sub {
    font-size: 0.95em;
    color: rgba(255,255,255,0.8);
    margin-bottom: var(--spacing-lg);
}

/* ========================================
   Key Takeaways
   ======================================== */
.takeaways {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: var(--spacing-md);
    margin-top: var(--spacing-lg);
}
.takeaway-item {
    background: rgba(255,255,255,0.08);
    border: 1px solid rgba(255,255,255,0.15);
    border-radius: var(--radius-base);
    padding: var(--spacing-md);
    display: flex;
    align-items: flex-start;
    gap: var(--spacing-sm);
}
.takeaway-icon {
    font-size: 1.3em;
    flex-shrink: 0;
    margin-top: 2px;
}
.takeaway-text {
    font-size: 0.85em;
    line-height: 1.5;
    color: rgba(255,255,255,0.95);
}

/* ========================================
   Section Headers
   ======================================== */
.section-block {
    margin-bottom: var(--spacing-2xl);
}
.section-header {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    margin-bottom: var(--spacing-lg);
    padding-bottom: var(--spacing-sm);
    border-bottom: 3px solid var(--color-aws-orange);
}
.section-header h2 {
    font-size: 1.5em;
    font-weight: var(--font-weight-bold);
    color: var(--color-text-primary);
    border-bottom: none;
    padding-bottom: 0;
    margin-bottom: 0;
}
.section-emoji {
    font-size: 1.4em;
}

/* ========================================
   Analogy Section
   ======================================== */
.analogy-box {
    background: linear-gradient(135deg, #FFF7ED 0%, #FFFBEB 100%);
    border: 2px solid #FDBA74;
    border-radius: var(--radius-lg);
    padding: var(--spacing-xl);
    margin-bottom: var(--spacing-lg);
}
.analogy-title {
    font-size: 1.2em;
    font-weight: var(--font-weight-bold);
    color: #92400E;
    margin-bottom: var(--spacing-md);
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
}
.analogy-content {
    font-size: 0.95em;
    color: #78350F;
    line-height: 1.8;
}

/* ========================================
   Mapping Table
   ======================================== */
.mapping-table {
    width: 100%;
    border-collapse: separate;
    border-spacing: 0;
    border-radius: var(--radius-base);
    overflow: hidden;
    margin-bottom: var(--spacing-lg);
    box-shadow: var(--shadow-sm);
}
.mapping-table thead th {
    background: var(--color-aws-dark);
    color: var(--color-text-white);
    padding: var(--spacing-md) var(--spacing-base);
    font-weight: var(--font-weight-semibold);
    font-size: 0.9em;
    text-align: left;
}
.mapping-table tbody td {
    padding: var(--spacing-md) var(--spacing-base);
    border-bottom: 1px solid var(--color-border-light);
    font-size: 0.9em;
    vertical-align: top;
}
.mapping-table tbody tr:nth-child(even) {
    background: var(--color-bg-light);
}
.mapping-table tbody tr:hover {
    background: #FFF7ED;
}

/* ========================================
   Concept Cards (Equal Grid)
   ======================================== */
.concept-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: var(--spacing-base);
    margin-bottom: var(--spacing-lg);
}
.concept-card {
    background: var(--color-bg-white);
    border-radius: var(--radius-lg);
    padding: var(--spacing-lg);
    box-shadow: var(--shadow-sm);
    border-top: 4px solid var(--color-info);
    transition: all var(--transition-base);
}
.concept-card:hover {
    transform: translateY(-3px);
    box-shadow: var(--shadow-md);
}
.concept-card.orange { border-top-color: var(--color-aws-orange); }
.concept-card.green { border-top-color: var(--color-success); }
.concept-card.purple { border-top-color: #8B5CF6; }
.concept-card.red { border-top-color: var(--color-error); }
.concept-card-title {
    font-size: 1.05em;
    font-weight: var(--font-weight-bold);
    margin-bottom: var(--spacing-sm);
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
}
.concept-card-desc {
    font-size: 0.88em;
    color: var(--color-text-secondary);
    line-height: 1.7;
}

/* ========================================
   SVG Diagram Container
   ======================================== */
.diagram-container {
    background: var(--color-bg-light);
    border-radius: var(--radius-lg);
    padding: var(--spacing-base);
    margin-bottom: var(--spacing-lg);
    overflow-x: auto;
}
.diagram-container svg {
    display: block;
    margin: 0 auto;
    max-width: 100%;
    height: auto;
}
.diagram-caption {
    text-align: center;
    font-size: 0.82em;
    color: var(--color-text-secondary);
    margin-top: var(--spacing-sm);
    font-weight: var(--font-weight-medium);
}

/* ========================================
   Info Callout
   ======================================== */
.callout {
    border-radius: var(--radius-base);
    padding: var(--spacing-base) var(--spacing-lg);
    margin-bottom: var(--spacing-lg);
    display: flex;
    align-items: flex-start;
    gap: var(--spacing-md);
}
.callout-icon { font-size: 1.3em; flex-shrink: 0; margin-top: 2px; }
.callout-content { font-size: 0.9em; line-height: 1.7; }
.callout-warning {
    background: #FEF3C7;
    border-left: 4px solid var(--color-warning);
}
.callout-info {
    background: #EFF6FF;
    border-left: 4px solid var(--color-info);
}
.callout-danger {
    background: #FEF2F2;
    border-left: 4px solid var(--color-error);
}
.callout-success {
    background: #ECFDF5;
    border-left: 4px solid var(--color-success);
}

/* ========================================
   Routing Path Steps
   ======================================== */
.routing-path {
    position: relative;
    padding-left: 50px;
    margin-bottom: var(--spacing-lg);
}
.routing-path::before {
    content: '';
    position: absolute;
    left: 20px;
    top: 0;
    bottom: 0;
    width: 3px;
    background: linear-gradient(180deg, var(--color-info), var(--color-success));
}
.path-step {
    position: relative;
    margin-bottom: var(--spacing-base);
    background: var(--color-bg-white);
    border-radius: var(--radius-base);
    padding: var(--spacing-md) var(--spacing-lg);
    box-shadow: var(--shadow-sm);
    border-left: 3px solid var(--color-info);
}
.path-step::before {
    content: attr(data-step);
    position: absolute;
    left: -42px;
    top: 50%;
    transform: translateY(-50%);
    width: 32px;
    height: 32px;
    background: var(--color-info);
    color: var(--color-text-white);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 0.75em;
    font-weight: var(--font-weight-bold);
}
.path-step-title {
    font-weight: var(--font-weight-bold);
    margin-bottom: 4px;
    font-size: 0.95em;
}
.path-step-desc {
    font-size: 0.85em;
    color: var(--color-text-secondary);
}

/* ========================================
   Code Block with Tabs
   ======================================== */
.code-section {
    background: var(--color-bg-light);
    border-radius: var(--radius-lg);
    overflow: hidden;
    margin-bottom: var(--spacing-lg);
    box-shadow: var(--shadow-sm);
}
.code-tabs {
    display: flex;
    background: var(--color-aws-dark);
    overflow-x: auto;
}
.code-tab {
    padding: var(--spacing-sm) var(--spacing-base);
    color: rgba(255,255,255,0.6);
    font-size: 0.8em;
    font-weight: var(--font-weight-semibold);
    cursor: pointer;
    border: none;
    background: none;
    white-space: nowrap;
    transition: all var(--transition-base);
}
.code-tab.active {
    color: var(--color-aws-orange-original);
    background: rgba(255,153,0,0.1);
    border-bottom: 2px solid var(--color-aws-orange-original);
}
.code-tab:hover { color: rgba(255,255,255,0.9); }
.code-panel {
    display: none;
    padding: var(--spacing-base);
    overflow-x: auto;
}
.code-panel.active { display: block; }
.code-panel pre {
    font-family: 'Consolas', 'Monaco', 'Courier New', monospace;
    font-size: 0.78em;
    line-height: 1.6;
    color: #1F2937;
    white-space: pre;
    margin: 0;
}
.code-comment { color: #6B7280; }
.code-keyword { color: #7C3AED; font-weight: var(--font-weight-semibold); }
.code-string { color: #059669; }
.code-param { color: #2563EB; }

/* ========================================
   Best Practices / Anti-patterns
   ======================================== */
.practices-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: var(--spacing-base);
    margin-bottom: var(--spacing-lg);
}
.practice-card {
    border-radius: var(--radius-lg);
    padding: var(--spacing-lg);
    box-shadow: var(--shadow-sm);
}
.practice-card.good {
    background: #F0FDF4;
    border: 1px solid #BBF7D0;
}
.practice-card.bad {
    background: #FEF2F2;
    border: 1px solid #FECACA;
}
.practice-label {
    font-size: 0.85em;
    font-weight: var(--font-weight-bold);
    margin-bottom: var(--spacing-sm);
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
}
.practice-card.good .practice-label { color: #166534; }
.practice-card.bad .practice-label { color: #991B1B; }
.practice-item {
    font-size: 0.85em;
    color: var(--color-text-primary);
    padding: var(--spacing-xs) 0;
    line-height: 1.6;
}

/* ========================================
   Troubleshooting
   ======================================== */
.trouble-card {
    background: var(--color-bg-white);
    border-radius: var(--radius-base);
    padding: var(--spacing-lg);
    margin-bottom: var(--spacing-md);
    box-shadow: var(--shadow-sm);
    border-left: 4px solid var(--color-error);
}
.trouble-symptom {
    font-weight: var(--font-weight-bold);
    color: #991B1B;
    margin-bottom: var(--spacing-xs);
    font-size: 0.95em;
}
.trouble-cause {
    font-size: 0.85em;
    color: var(--color-text-secondary);
    margin-bottom: var(--spacing-xs);
}
.trouble-fix {
    font-size: 0.85em;
    color: #166534;
    background: #F0FDF4;
    padding: var(--spacing-sm) var(--spacing-md);
    border-radius: var(--radius-sm);
}

/* ========================================
   FAQ Accordion
   ======================================== */
.faq-item {
    background: var(--color-bg-white);
    border-radius: var(--radius-base);
    margin-bottom: var(--spacing-sm);
    box-shadow: var(--shadow-sm);
    overflow: hidden;
}
.faq-question {
    width: 100%;
    text-align: left;
    padding: var(--spacing-md) var(--spacing-lg);
    background: none;
    border: none;
    font-size: 0.92em;
    font-weight: var(--font-weight-semibold);
    color: var(--color-text-primary);
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: var(--spacing-sm);
    font-family: inherit;
    transition: background var(--transition-base);
}
.faq-question:hover { background: var(--color-bg-light); }
.faq-toggle {
    font-size: 1.2em;
    color: var(--color-aws-orange);
    transition: transform var(--transition-base);
    flex-shrink: 0;
}
.faq-item.open .faq-toggle { transform: rotate(45deg); }
.faq-answer {
    display: none;
    padding: 0 var(--spacing-lg) var(--spacing-lg);
    font-size: 0.88em;
    color: var(--color-text-secondary);
    line-height: 1.8;
}
.faq-item.open .faq-answer { display: block; }

/* ========================================
   Cheat Sheet
   ======================================== */
.cheat-sheet {
    background: linear-gradient(135deg, #1E293B 0%, #0F172A 100%);
    border-radius: var(--radius-xl);
    padding: var(--spacing-xl);
    color: var(--color-text-white);
    margin-bottom: var(--spacing-lg);
}
.cheat-title {
    font-size: 1.3em;
    font-weight: var(--font-weight-bold);
    margin-bottom: var(--spacing-lg);
    color: var(--color-aws-orange-original);
}
.cheat-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: var(--spacing-md);
}
.cheat-item {
    background: rgba(255,255,255,0.06);
    border: 1px solid rgba(255,255,255,0.1);
    border-radius: var(--radius-base);
    padding: var(--spacing-md);
}
.cheat-item-title {
    font-weight: var(--font-weight-bold);
    color: var(--color-aws-orange-original);
    font-size: 0.88em;
    margin-bottom: var(--spacing-xs);
}
.cheat-item-content {
    font-size: 0.82em;
    line-height: 1.6;
    color: rgba(255,255,255,0.85);
}

/* ========================================
   Exam Tips
   ======================================== */
.exam-tip {
    background: linear-gradient(135deg, #EEF2FF 0%, #E0E7FF 100%);
    border: 2px solid #818CF8;
    border-radius: var(--radius-lg);
    padding: var(--spacing-lg);
    margin-bottom: var(--spacing-lg);
}
.exam-tip-title {
    font-weight: var(--font-weight-bold);
    color: #3730A3;
    margin-bottom: var(--spacing-sm);
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    font-size: 1.05em;
}
.exam-tip-content {
    font-size: 0.88em;
    color: #312E81;
    line-height: 1.8;
}

/* ========================================
   Responsive
   ======================================== */
@media (max-width: 768px) {
    .takeaways,
    .concept-grid,
    .practices-grid,
    .cheat-grid { grid-template-columns: 1fr; }
    .hero h1 { font-size: 1.4em; }
    .mapping-table { font-size: 0.85em; }
}