/**
 * PingTest.in — Design System & Global Styles
 * Clean, modern, technical network diagnostic utility theme.
 */

/* ========================================
   1. Design Tokens (CSS Custom Properties)
   ======================================== */

:root {
    /* Primary Brand Colors */
    --color-primary: #0A66C2;
    --color-primary-dark: #084E96;
    --color-primary-light: #E8F1FB;
    --color-primary-rgb: 10, 102, 194;

    /* Secondary / Accents */
    --color-secondary: #00B4D8;
    --color-secondary-dark: #0096B7;

    /* Status Colors */
    --color-success: #059669;
    --color-success-light: #ECFDF5;
    --color-warning: #D97706;
    --color-warning-light: #FFFBEB;
    --color-danger: #DC2626;
    --color-danger-light: #FEF2F2;

    /* Typography / Neutral Colors */
    --color-text: #0F172A;
    --color-text-secondary: #475569;
    --color-text-muted: #94A3B8;

    /* Backgrounds */
    --color-bg: #FFFFFF;
    --color-bg-secondary: #F8FAFC;
    --color-bg-tertiary: #F1F5F9;

    /* Borders */
    --color-border: #E2E8F0;
    --color-border-light: #F1F5F9;

    /* Shadows */
    --shadow-xs: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
    --shadow-sm: 0 1px 3px 0 rgba(0, 0, 0, 0.1), 0 1px 2px -1px rgba(0, 0, 0, 0.1);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -2px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -4px rgba(0, 0, 0, 0.1);

    /* Border Radius */
    --radius-sm: 6px;
    --radius-md: 8px;
    --radius-lg: 12px;
    --radius-xl: 16px;
    --radius-full: 9999px;

    /* Typography */
    --font-sans: system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    --font-mono: ui-monospace, 'SF Mono', 'Fira Code', 'Fira Mono', 'Roboto Mono', monospace;
    --font-size-xs: 0.75rem;
    --font-size-sm: 0.875rem;
    --font-size-base: 1rem;
    --font-size-lg: 1.125rem;
    --font-size-xl: 1.25rem;
    --font-size-2xl: 1.5rem;
    --font-size-3xl: 1.875rem;
    --font-size-4xl: 2.25rem;
    --line-height-tight: 1.25;
    --line-height-normal: 1.5;
    --line-height-relaxed: 1.75;
    --font-weight-normal: 400;
    --font-weight-medium: 500;
    --font-weight-semibold: 600;
    --font-weight-bold: 700;

    /* Layout Containers */
    --container-sm: 640px;
    --container-md: 768px;
    --container-lg: 1024px;
    --container-xl: 1140px;
    --header-height: 64px;

    /* Spacing Units */
    --spacing-xs: 0.25rem;
    --spacing-sm: 0.5rem;
    --spacing-md: 1rem;
    --spacing-lg: 1.5rem;
    --spacing-xl: 2rem;
    --spacing-2xl: 3rem;
    --spacing-3xl: 4rem;

    /* Transitions */
    --transition-fast: 150ms ease;
    --transition-normal: 250ms ease;
    --transition-slow: 350ms ease;
}

@media (prefers-reduced-motion: reduce) {
    :root {
        --transition-fast: 0ms;
        --transition-normal: 0ms;
        --transition-slow: 0ms;
    }
    *, *::before, *::after {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
    }
}

/* ========================================
   2. Reset & Base Elements
   ======================================== */

*, *::before, *::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

html {
    font-size: 16px;
    scroll-behavior: smooth;
    -webkit-text-size-adjust: 100%;
}

body {
    font-family: var(--font-sans);
    font-size: var(--font-size-base);
    line-height: var(--line-height-normal);
    color: var(--color-text);
    background-color: var(--color-bg);
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

main.site-main {
    flex: 1;
}

a {
    color: var(--color-primary);
    text-decoration: none;
    transition: color var(--transition-fast);
}

a:hover {
    color: var(--color-primary-dark);
    text-decoration: underline;
}

a:focus-visible, button:focus-visible {
    outline: 2px solid var(--color-primary);
    outline-offset: 2px;
    border-radius: var(--radius-sm);
}

ul, ol {
    list-style: none;
}

button {
    cursor: pointer;
    font-family: inherit;
    font-size: inherit;
    border: none;
    background: none;
    color: inherit;
}

code {
    font-family: var(--font-mono);
    font-size: 0.9em;
    background: var(--color-bg-tertiary);
    padding: 0.125em 0.375em;
    border-radius: var(--radius-sm);
    color: var(--color-primary-dark);
}

/* ========================================
   3. Common Layout & Utilities
   ======================================== */

.container {
    width: 100%;
    max-width: var(--container-xl);
    margin-left: auto;
    margin-right: auto;
    padding-left: var(--spacing-lg);
    padding-right: var(--spacing-lg);
}

.container-md {
    max-width: var(--container-md);
}

.section {
    padding-top: var(--spacing-3xl);
    padding-bottom: var(--spacing-3xl);
}

.section-alt {
    background-color: var(--color-bg-secondary);
}

.section-header {
    text-align: center;
    margin-bottom: var(--spacing-2xl);
}

.section-title {
    font-size: var(--font-size-2xl);
    font-weight: var(--font-weight-bold);
    color: var(--color-text);
    margin-bottom: var(--spacing-sm);
}

.section-subtitle {
    font-size: var(--font-size-lg);
    color: var(--color-text-secondary);
    max-width: 620px;
    margin-left: auto;
    margin-right: auto;
}

/* ========================================
   4. Header & Navigation
   ======================================== */

.site-header {
    position: sticky;
    top: 0;
    z-index: 100;
    background: rgba(255, 255, 255, 0.96);
    backdrop-filter: blur(10px);
    -webkit-backdrop-filter: blur(10px);
    border-bottom: 1px solid var(--color-border);
    height: var(--header-height);
}

.header-inner {
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 100%;
}

.site-logo {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    text-decoration: none;
    font-weight: var(--font-weight-bold);
    font-size: var(--font-size-xl);
    color: var(--color-text);
}

.site-logo:hover {
    text-decoration: none;
}

.logo-icon {
    color: var(--color-primary);
}

.logo-ping {
    color: var(--color-primary);
}

.logo-test {
    color: var(--color-text);
}

.logo-dot {
    color: var(--color-text-muted);
}

.nav-links {
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
}

.nav-link {
    display: inline-flex;
    align-items: center;
    padding: var(--spacing-sm) var(--spacing-md);
    font-size: var(--font-size-sm);
    font-weight: var(--font-weight-medium);
    color: var(--color-text-secondary);
    border-radius: var(--radius-md);
    transition: color var(--transition-fast), background-color var(--transition-fast);
}

.nav-link:hover, .nav-link.active {
    color: var(--color-primary);
    background-color: var(--color-primary-light);
    text-decoration: none;
}

.nav-toggle {
    display: none;
    width: 40px;
    height: 40px;
    border-radius: var(--radius-md);
    align-items: center;
    justify-content: center;
}

.nav-toggle-icon {
    display: flex;
    flex-direction: column;
    gap: 5px;
    width: 20px;
}

.nav-toggle-icon span {
    display: block;
    width: 100%;
    height: 2px;
    background-color: var(--color-text);
    border-radius: 1px;
    transition: transform var(--transition-fast), opacity var(--transition-fast);
}

.nav-toggle.active .nav-toggle-icon span:nth-child(1) {
    transform: translateY(7px) rotate(45deg);
}

.nav-toggle.active .nav-toggle-icon span:nth-child(2) {
    opacity: 0;
}

.nav-toggle.active .nav-toggle-icon span:nth-child(3) {
    transform: translateY(-7px) rotate(-45deg);
}

/* ========================================
   5. Buttons & Badges
   ======================================== */

.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-sm);
    padding: 0.625rem 1.25rem;
    font-size: var(--font-size-sm);
    font-weight: var(--font-weight-semibold);
    border-radius: var(--radius-md);
    border: 1px solid transparent;
    transition: all var(--transition-fast);
    text-decoration: none;
    white-space: nowrap;
}

.btn:hover {
    text-decoration: none;
}

.btn-primary {
    background-color: var(--color-primary);
    color: #FFFFFF;
    border-color: var(--color-primary);
}

.btn-primary:hover {
    background-color: var(--color-primary-dark);
    border-color: var(--color-primary-dark);
    color: #FFFFFF;
}

.btn-danger {
    background-color: var(--color-danger);
    color: #FFFFFF;
    border-color: var(--color-danger);
}

.btn-danger:hover {
    background-color: #B91C1C;
    border-color: #B91C1C;
    color: #FFFFFF;
}

.btn-outline {
    background-color: transparent;
    color: var(--color-primary);
    border-color: var(--color-primary);
}

.btn-outline:hover {
    background-color: var(--color-primary);
    color: #FFFFFF;
}

.btn-lg {
    padding: 0.75rem 1.75rem;
    font-size: var(--font-size-base);
    border-radius: var(--radius-lg);
}

.badge {
    display: inline-flex;
    align-items: center;
    padding: 0.125rem 0.625rem;
    font-size: var(--font-size-xs);
    font-weight: var(--font-weight-semibold);
    border-radius: var(--radius-full);
}

.badge-info {
    background-color: var(--color-primary-light);
    color: var(--color-primary-dark);
}

.badge-coming-soon {
    background-color: var(--color-bg-tertiary);
    color: var(--color-text-muted);
}

/* ========================================
   6. Hero Section
   ======================================== */

.hero {
    padding: var(--spacing-3xl) 0;
    background: linear-gradient(180deg, var(--color-primary-light) 0%, var(--color-bg) 100%);
    text-align: center;
}

.hero-content {
    max-width: 760px;
    margin: 0 auto;
}

.hero-title {
    font-size: var(--font-size-3xl);
    font-weight: var(--font-weight-bold);
    color: var(--color-text);
    margin-bottom: var(--spacing-md);
    letter-spacing: -0.02em;
    line-height: var(--line-height-tight);
}

.hero-subtitle {
    font-size: var(--font-size-lg);
    color: var(--color-text-secondary);
    margin-bottom: var(--spacing-xl);
    line-height: var(--line-height-relaxed);
}

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

.hero-note {
    display: inline-flex;
    align-items: flex-start;
    gap: var(--spacing-xs);
    font-size: var(--font-size-sm);
    color: var(--color-text-muted);
    max-width: 580px;
    text-align: left;
    margin: 0 auto;
    padding: var(--spacing-sm) var(--spacing-md);
    background: var(--color-bg);
    border-radius: var(--radius-md);
    border: 1px solid var(--color-border-light);
}

.hero-note svg {
    flex-shrink: 0;
    margin-top: 2px;
}

/* ========================================
   7. Ping Tool & Results Dashboard
   ======================================== */

.ping-tool {
    background: var(--color-bg);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-xl);
    padding: var(--spacing-2xl);
    box-shadow: var(--shadow-md);
}

.ping-tool-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-bottom: var(--spacing-xl);
    flex-wrap: wrap;
    gap: var(--spacing-md);
}

.ping-tool-title {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
}

.ping-tool-title h2 {
    font-size: var(--font-size-xl);
    font-weight: var(--font-weight-bold);
}

.ping-tool-status {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    font-size: var(--font-size-sm);
    color: var(--color-text-secondary);
}

.status-dot {
    width: 8px;
    height: 8px;
    border-radius: 50%;
    flex-shrink: 0;
}

.status-dot.status-neutral { background-color: var(--color-text-muted); }
.status-dot.status-good, .status-dot.status-ok { background-color: var(--color-success); }
.status-dot.status-warning { background-color: var(--color-warning); }
.status-dot.status-danger { background-color: var(--color-danger); }
.status-dot.status-testing {
    background-color: var(--color-primary);
    animation: pulse 1.5s infinite;
}

@keyframes pulse {
    0%, 100% { opacity: 1; }
    50% { opacity: 0.3; }
}

.ping-controls {
    display: flex;
    justify-content: center;
    gap: var(--spacing-md);
    margin-bottom: var(--spacing-xl);
    flex-wrap: wrap;
}

.ping-progress {
    margin-bottom: var(--spacing-xl);
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
}

.progress-bar-track {
    flex: 1;
    height: 8px;
    background: var(--color-bg-tertiary);
    border-radius: var(--radius-full);
    overflow: hidden;
}

.progress-bar-fill {
    height: 100%;
    background: var(--color-primary);
    border-radius: var(--radius-full);
    transition: width var(--transition-fast);
}

.progress-text {
    font-size: var(--font-size-sm);
    color: var(--color-text-muted);
    font-variant-numeric: tabular-nums;
    min-width: 50px;
    text-align: right;
}

/* Results Grid */
.results-dashboard {
    margin-bottom: var(--spacing-lg);
}

.results-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: var(--spacing-md);
}

.stat-card {
    text-align: center;
    padding: var(--spacing-lg);
    background: var(--color-bg-secondary);
    border-radius: var(--radius-lg);
    border: 1px solid var(--color-border-light);
    transition: border-color var(--transition-fast);
}

.stat-icon {
    color: var(--color-text-muted);
    margin-bottom: var(--spacing-sm);
    display: flex;
    justify-content: center;
}

.stat-value {
    font-size: var(--font-size-2xl);
    font-weight: var(--font-weight-bold);
    color: var(--color-text);
    font-variant-numeric: tabular-nums;
    line-height: 1;
    margin-bottom: var(--spacing-xs);
}

.stat-value-secondary {
    font-size: var(--font-size-xl);
    color: var(--color-text-secondary);
}

.stat-separator {
    font-size: var(--font-size-lg);
    color: var(--color-text-muted);
    margin: 0 var(--spacing-xs);
    display: inline;
}

.stat-unit {
    font-size: var(--font-size-sm);
    color: var(--color-text-muted);
    font-weight: var(--font-weight-medium);
    margin-bottom: var(--spacing-xs);
}

.stat-label {
    font-size: var(--font-size-xs);
    color: var(--color-text-muted);
    font-weight: var(--font-weight-medium);
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.stat-card[data-status="good"] { border-color: var(--color-success); }
.stat-card[data-status="good"] .stat-value { color: var(--color-success); }
.stat-card[data-status="warning"] { border-color: var(--color-warning); }
.stat-card[data-status="warning"] .stat-value { color: var(--color-warning); }
.stat-card[data-status="danger"] { border-color: var(--color-danger); }
.stat-card[data-status="danger"] .stat-value { color: var(--color-danger); }

/* Samples Visualization */
.samples-section {
    margin-top: var(--spacing-xl);
    padding-top: var(--spacing-xl);
    border-top: 1px solid var(--color-border-light);
}

.samples-title {
    font-size: var(--font-size-sm);
    font-weight: var(--font-weight-semibold);
    color: var(--color-text-secondary);
    margin-bottom: var(--spacing-md);
}

.samples-visualization {
    display: flex;
    align-items: flex-end;
    gap: 6px;
    height: 120px;
    padding: var(--spacing-sm) 0;
}

.sample-bar {
    flex: 1;
    min-width: 0;
    border-radius: var(--radius-sm) var(--radius-sm) 0 0;
    transition: height var(--transition-fast);
    position: relative;
    cursor: default;
}

.sample-bar.status-good { background-color: var(--color-success); }
.sample-bar.status-warning { background-color: var(--color-warning); }
.sample-bar.status-danger { background-color: var(--color-danger); }
.sample-bar.status-failed {
    background-color: var(--color-border);
    min-height: 4px;
}

.sample-bar-tooltip {
    position: absolute;
    bottom: 100%;
    left: 50%;
    transform: translateX(-50%);
    background: var(--color-text);
    color: #FFFFFF;
    font-size: var(--font-size-xs);
    padding: 2px 6px;
    border-radius: var(--radius-sm);
    white-space: nowrap;
    opacity: 0;
    pointer-events: none;
    transition: opacity var(--transition-fast);
    margin-bottom: 4px;
}

.sample-bar:hover .sample-bar-tooltip {
    opacity: 1;
}

.samples-legend {
    display: flex;
    gap: var(--spacing-lg);
    margin-top: var(--spacing-md);
    flex-wrap: wrap;
}

.legend-item {
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
    font-size: var(--font-size-xs);
    color: var(--color-text-muted);
}

.legend-dot {
    width: 8px;
    height: 8px;
    border-radius: 50%;
}

.legend-dot.status-good { background-color: var(--color-success); }
.legend-dot.status-warning { background-color: var(--color-warning); }
.legend-dot.status-danger { background-color: var(--color-danger); }

.ping-tool-info {
    margin-top: var(--spacing-lg);
    padding: var(--spacing-md) var(--spacing-lg);
    background: var(--color-bg-secondary);
    border-radius: var(--radius-md);
    border: 1px solid var(--color-border-light);
}

.ping-tool-info p {
    font-size: var(--font-size-sm);
    color: var(--color-text-secondary);
    line-height: var(--line-height-relaxed);
    display: flex;
    align-items: flex-start;
    gap: var(--spacing-sm);
}

.ping-tool-info svg {
    flex-shrink: 0;
    margin-top: 3px;
}

/* ========================================
   8. Educational / Info Cards
   ======================================== */

.info-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: var(--spacing-xl);
}

.info-card {
    background: var(--color-bg);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-lg);
    padding: var(--spacing-xl);
}

.info-card-icon {
    color: var(--color-primary);
    margin-bottom: var(--spacing-md);
}

.info-card h3 {
    font-size: var(--font-size-lg);
    font-weight: var(--font-weight-semibold);
    margin-bottom: var(--spacing-sm);
}

.info-card p {
    color: var(--color-text-secondary);
    font-size: var(--font-size-sm);
    line-height: var(--line-height-relaxed);
    margin-bottom: var(--spacing-sm);
}

.info-card p:last-child {
    margin-bottom: 0;
}

.info-note {
    font-style: italic;
    color: var(--color-text-muted) !important;
    font-size: var(--font-size-xs) !important;
}

.info-thresholds {
    display: flex;
    gap: var(--spacing-sm);
    margin-top: var(--spacing-md);
    flex-wrap: wrap;
}

.threshold {
    display: flex;
    flex-direction: column;
    align-items: center;
    padding: var(--spacing-sm) var(--spacing-md);
    border-radius: var(--radius-md);
    flex: 1;
    min-width: 65px;
}

.threshold-range {
    font-size: var(--font-size-xs);
    font-weight: var(--font-weight-bold);
    font-variant-numeric: tabular-nums;
}

.threshold-label {
    font-size: var(--font-size-xs);
    font-weight: var(--font-weight-medium);
}

.threshold-good { background: var(--color-success-light); color: var(--color-success); }
.threshold-ok { background: #F0FDF4; color: #16A34A; }
.threshold-warning { background: var(--color-warning-light); color: var(--color-warning); }
.threshold-danger { background: var(--color-danger-light); color: var(--color-danger); }

/* ========================================
   9. Tools Grid & Cards
   ======================================== */

.tools-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: var(--spacing-lg);
}

.tool-card {
    background: var(--color-bg);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-lg);
    padding: var(--spacing-xl);
    transition: border-color var(--transition-fast), box-shadow var(--transition-fast);
    display: flex;
    flex-direction: column;
}

.tool-card:not(.tool-card-coming-soon):hover {
    border-color: var(--color-primary);
    box-shadow: var(--shadow-md);
}

.tool-card-coming-soon {
    opacity: 0.7;
}

.tool-card-icon {
    color: var(--color-primary);
    margin-bottom: var(--spacing-md);
    width: 48px;
    height: 48px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--color-primary-light);
    border-radius: var(--radius-md);
}

.tool-card-title {
    font-size: var(--font-size-base);
    font-weight: var(--font-weight-semibold);
    margin-bottom: var(--spacing-sm);
}

.tool-card-title a {
    color: var(--color-text);
    text-decoration: none;
}

.tool-card-title a:hover {
    color: var(--color-primary);
}

.tool-card-description {
    font-size: var(--font-size-sm);
    color: var(--color-text-secondary);
    line-height: var(--line-height-relaxed);
    margin-bottom: var(--spacing-md);
    flex: 1;
}

.tool-card-link {
    display: inline-flex;
    align-items: center;
    gap: var(--spacing-xs);
    font-size: var(--font-size-sm);
    font-weight: var(--font-weight-semibold);
    color: var(--color-primary);
}

/* ========================================
   10. Empty State
   ======================================== */

.empty-state {
    text-align: center;
    padding: var(--spacing-3xl) var(--spacing-xl);
}

.empty-state-icon {
    color: var(--color-text-muted);
    margin-bottom: var(--spacing-md);
    display: flex;
    justify-content: center;
    opacity: 0.5;
}

.empty-state-title {
    font-size: var(--font-size-xl);
    font-weight: var(--font-weight-semibold);
    color: var(--color-text);
    margin-bottom: var(--spacing-sm);
}

.empty-state-text {
    font-size: var(--font-size-base);
    color: var(--color-text-secondary);
    max-width: 450px;
    margin: 0 auto;
}

/* ========================================
   11. FAQ Accordion
   ======================================== */

.faq-list {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-sm);
}

.faq-item {
    border: 1px solid var(--color-border);
    border-radius: var(--radius-lg);
    background: var(--color-bg);
}

.faq-question {
    width: 100%;
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: var(--spacing-lg) var(--spacing-xl);
    font-size: var(--font-size-base);
    font-weight: var(--font-weight-semibold);
    color: var(--color-text);
    text-align: left;
    transition: background-color var(--transition-fast);
}

.faq-question:hover {
    background-color: var(--color-bg-secondary);
}

.faq-question svg {
    flex-shrink: 0;
    color: var(--color-text-muted);
    transition: transform var(--transition-normal);
}

.faq-question[aria-expanded="true"] svg {
    transform: rotate(180deg);
}

.faq-answer {
    max-height: 0;
    overflow: hidden;
    transition: max-height var(--transition-slow);
}

.faq-answer.open {
    max-height: 1000px;
}

.faq-answer p, .faq-answer ul {
    padding: 0 var(--spacing-xl);
    margin-bottom: var(--spacing-md);
    font-size: var(--font-size-sm);
    color: var(--color-text-secondary);
    line-height: var(--line-height-relaxed);
}

.faq-answer p:last-child, .faq-answer ul:last-child {
    padding-bottom: var(--spacing-lg);
}

.faq-answer ul {
    list-style: disc;
    padding-left: calc(var(--spacing-xl) + var(--spacing-lg));
}

.faq-answer li {
    margin-bottom: var(--spacing-xs);
}

/* ========================================
   12. Footer
   ======================================== */

.site-footer {
    background: var(--color-text);
    color: rgba(255, 255, 255, 0.7);
    padding-top: var(--spacing-3xl);
    padding-bottom: var(--spacing-xl);
    margin-top: auto;
}

.footer-main {
    display: grid;
    grid-template-columns: 2fr 1fr 1fr 1fr;
    gap: var(--spacing-2xl);
    padding-bottom: var(--spacing-2xl);
    border-bottom: 1px solid rgba(255, 255, 255, 0.1);
}

.footer-logo {
    font-size: var(--font-size-xl);
    font-weight: var(--font-weight-bold);
    display: inline-block;
    margin-bottom: var(--spacing-md);
    text-decoration: none;
}

.footer-logo .logo-ping { color: #60A5FA; }
.footer-logo .logo-test { color: #FFFFFF; }
.footer-logo .logo-dot { color: rgba(255, 255, 255, 0.5); }

.footer-description {
    font-size: var(--font-size-sm);
    line-height: var(--line-height-relaxed);
    max-width: 320px;
}

.footer-heading {
    font-size: var(--font-size-sm);
    font-weight: var(--font-weight-semibold);
    color: #FFFFFF;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    margin-bottom: var(--spacing-lg);
}

.footer-links {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-sm);
}

.footer-links a {
    font-size: var(--font-size-sm);
    color: rgba(255, 255, 255, 0.6);
    text-decoration: none;
    transition: color var(--transition-fast);
}

.footer-links a:hover {
    color: #FFFFFF;
}

.footer-bottom {
    padding-top: var(--spacing-xl);
    display: flex;
    align-items: center;
    justify-content: space-between;
    flex-wrap: wrap;
    gap: var(--spacing-md);
}

.footer-copyright {
    font-size: var(--font-size-sm);
}

.footer-note {
    font-size: var(--font-size-xs);
    color: rgba(255, 255, 255, 0.4);
}

/* ========================================
   13. Error 404 & Ad Slots
   ======================================== */

.error-page {
    text-align: center;
    padding: var(--spacing-3xl) var(--spacing-xl);
    max-width: 520px;
    margin: 0 auto;
}

.error-page-icon {
    color: var(--color-text-muted);
    margin-bottom: var(--spacing-lg);
    opacity: 0.4;
    display: flex;
    justify-content: center;
}

.error-page-title {
    font-size: var(--font-size-2xl);
    font-weight: var(--font-weight-bold);
    margin-bottom: var(--spacing-sm);
}

.error-page-message {
    font-size: var(--font-size-base);
    color: var(--color-text-secondary);
    margin-bottom: var(--spacing-xl);
}

.error-page-actions {
    margin-bottom: var(--spacing-xl);
}

.ad-placement {
    margin: var(--spacing-lg) auto;
    max-width: var(--container-lg);
    min-height: 90px;
    display: flex;
    align-items: center;
    justify-content: center;
}