/* =============================================
   CSS Design System — HBH SpotMe Guide
   Makmal Logam Berat
   ============================================= */

/* ---------- CSS Custom Properties ---------- */
:root {
    /* Color Palette — Professional government-inspired */
    --clr-primary: #0b6e4f;
    --clr-primary-light: #14a373;
    --clr-primary-dark: #064a35;
    --clr-primary-glow: rgba(11, 110, 79, 0.15);
    
    --clr-accent: #f0a500;
    --clr-accent-light: #ffd166;
    --clr-accent-dark: #c98600;
    
    --clr-bg: #0a0e17;
    --clr-bg-card: rgba(15, 23, 42, 0.7);
    --clr-bg-card-hover: rgba(20, 30, 55, 0.85);
    --clr-surface: #111827;
    --clr-surface-2: #1e293b;
    
    --clr-text: #e2e8f0;
    --clr-text-muted: #94a3b8;
    --clr-text-dim: #64748b;
    --clr-heading: #f1f5f9;
    
    --clr-success: #22c55e;
    --clr-warning: #f59e0b;
    --clr-danger: #ef4444;
    --clr-info: #3b82f6;
    
    --clr-border: rgba(148, 163, 184, 0.12);
    --clr-glass: rgba(255, 255, 255, 0.04);
    --clr-glass-border: rgba(255, 255, 255, 0.08);
    
    /* Typography */
    --font-primary: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
    --font-mono: 'JetBrains Mono', monospace;
    
    /* Spacing */
    --space-xs: 0.25rem;
    --space-sm: 0.5rem;
    --space-md: 1rem;
    --space-lg: 1.5rem;
    --space-xl: 2rem;
    --space-2xl: 3rem;
    --space-3xl: 4rem;
    --space-4xl: 6rem;
    
    /* Borders */
    --radius-sm: 8px;
    --radius-md: 12px;
    --radius-lg: 16px;
    --radius-xl: 24px;
    --radius-full: 999px;
    
    /* Shadows */
    --shadow-sm: 0 1px 3px rgba(0,0,0,0.3);
    --shadow-md: 0 4px 12px rgba(0,0,0,0.4);
    --shadow-lg: 0 8px 32px rgba(0,0,0,0.5);
    --shadow-glow: 0 0 40px var(--clr-primary-glow);
    
    /* Transitions */
    --ease-smooth: cubic-bezier(0.4, 0, 0.2, 1);
    --ease-bounce: cubic-bezier(0.34, 1.56, 0.64, 1);
    --duration-fast: 150ms;
    --duration-normal: 300ms;
    --duration-slow: 500ms;
}

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

html {
    scroll-behavior: smooth;
    scroll-padding-top: 80px;
    font-size: 16px;
}

body {
    font-family: var(--font-primary);
    background: var(--clr-bg);
    color: var(--clr-text);
    line-height: 1.7;
    overflow-x: hidden;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

::selection {
    background: var(--clr-primary);
    color: white;
}

img {
    max-width: 100%;
    height: auto;
    display: block;
}

a {
    color: var(--clr-primary-light);
    text-decoration: none;
    transition: color var(--duration-fast) var(--ease-smooth);
}

a:hover {
    color: var(--clr-accent);
}

code {
    font-family: var(--font-mono);
    font-size: 0.875em;
    background: rgba(11, 110, 79, 0.15);
    color: var(--clr-primary-light);
    padding: 2px 8px;
    border-radius: 4px;
    border: 1px solid rgba(11, 110, 79, 0.2);
}

strong {
    color: var(--clr-heading);
    font-weight: 600;
}

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

/* ---------- Animated Background ---------- */
.bg-animation {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    pointer-events: none;
    z-index: 0;
    overflow: hidden;
}

.bg-orb {
    position: absolute;
    border-radius: 50%;
    filter: blur(100px);
    opacity: 0.3;
    animation: orbFloat 20s ease-in-out infinite;
}

.bg-orb-1 {
    width: 600px;
    height: 600px;
    background: radial-gradient(circle, var(--clr-primary) 0%, transparent 70%);
    top: -200px;
    right: -200px;
    animation-delay: 0s;
}

.bg-orb-2 {
    width: 500px;
    height: 500px;
    background: radial-gradient(circle, var(--clr-accent) 0%, transparent 70%);
    bottom: -150px;
    left: -150px;
    animation-delay: -7s;
    opacity: 0.15;
}

.bg-orb-3 {
    width: 400px;
    height: 400px;
    background: radial-gradient(circle, var(--clr-info) 0%, transparent 70%);
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    animation-delay: -14s;
    opacity: 0.1;
}

@keyframes orbFloat {
    0%, 100% { transform: translate(0, 0) scale(1); }
    25% { transform: translate(30px, -40px) scale(1.05); }
    50% { transform: translate(-20px, 20px) scale(0.95); }
    75% { transform: translate(40px, 30px) scale(1.02); }
}

/* ---------- Progress Bar ---------- */
.progress-bar {
    position: fixed;
    top: 0;
    left: 0;
    height: 3px;
    background: linear-gradient(90deg, var(--clr-primary), var(--clr-accent), var(--clr-primary-light));
    z-index: 10000;
    width: 0%;
    transition: width 100ms linear;
}

/* ---------- Hero Section ---------- */
.hero {
    position: relative;
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: var(--space-2xl);
    text-align: center;
    z-index: 1;
    overflow: hidden;
}

.hero::before {
    content: '';
    position: absolute;
    inset: 0;
    background: radial-gradient(ellipse at center bottom, var(--clr-primary-glow) 0%, transparent 60%);
    pointer-events: none;
}

.hero-content {
    max-width: 800px;
    animation: fadeInUp 1s var(--ease-smooth);
}

.hero-badge {
    display: inline-flex;
    align-items: center;
    gap: var(--space-sm);
    padding: var(--space-sm) var(--space-lg);
    background: var(--clr-glass);
    border: 1px solid var(--clr-glass-border);
    border-radius: var(--radius-full);
    font-size: 0.875rem;
    color: var(--clr-text-muted);
    margin-bottom: var(--space-xl);
    backdrop-filter: blur(8px);
}

.badge-icon {
    font-size: 1.1rem;
}

.hero-title {
    display: flex;
    flex-direction: column;
    gap: var(--space-xs);
    margin-bottom: var(--space-xl);
}

.title-line {
    font-size: clamp(1rem, 2.5vw, 1.25rem);
    font-weight: 400;
    text-transform: uppercase;
    letter-spacing: 0.2em;
    color: var(--clr-text-muted);
}

.title-accent {
    font-size: clamp(2.5rem, 6vw, 4rem);
    font-weight: 800;
    background: linear-gradient(135deg, var(--clr-primary-light), var(--clr-accent));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    line-height: 1.1;
}

.title-system {
    font-size: clamp(1.25rem, 3vw, 1.75rem);
    font-weight: 600;
    color: var(--clr-heading);
    margin-top: var(--space-sm);
}

.hero-subtitle {
    font-size: 1.1rem;
    color: var(--clr-text-muted);
    max-width: 600px;
    margin: 0 auto var(--space-2xl);
    line-height: 1.8;
}

.hero-stats {
    display: flex;
    justify-content: center;
    gap: var(--space-3xl);
    margin-bottom: var(--space-2xl);
    flex-wrap: wrap;
}

.stat {
    display: flex;
    flex-direction: column;
    align-items: center;
}

.stat-number {
    font-size: 2.5rem;
    font-weight: 800;
    color: var(--clr-primary-light);
    line-height: 1;
}

.stat-label {
    font-size: 0.8rem;
    color: var(--clr-text-dim);
    text-transform: uppercase;
    letter-spacing: 0.1em;
    margin-top: var(--space-xs);
}

.hero-cta {
    display: inline-flex;
    align-items: center;
    gap: var(--space-sm);
    padding: var(--space-md) var(--space-xl);
    background: linear-gradient(135deg, var(--clr-primary), var(--clr-primary-dark));
    color: white;
    border-radius: var(--radius-full);
    font-weight: 600;
    font-size: 1rem;
    transition: all var(--duration-normal) var(--ease-smooth);
    box-shadow: 0 4px 20px rgba(11, 110, 79, 0.3);
    border: 1px solid rgba(255,255,255,0.1);
}

.hero-cta:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 30px rgba(11, 110, 79, 0.4);
    color: white;
}

.hero-cta svg {
    animation: bounce 2s infinite;
}

@keyframes bounce {
    0%, 20%, 50%, 80%, 100% { transform: translateY(0); }
    40% { transform: translateY(6px); }
    60% { transform: translateY(3px); }
}

/* ---------- Sticky Navigation ---------- */
.sticky-nav {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    background: rgba(10, 14, 23, 0.85);
    backdrop-filter: blur(16px);
    border-bottom: 1px solid var(--clr-border);
    transform: translateY(-100%);
    transition: transform var(--duration-normal) var(--ease-smooth);
}

.sticky-nav.visible {
    transform: translateY(0);
}

.nav-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--space-xl);
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 60px;
}

.nav-logo {
    display: flex;
    align-items: center;
    gap: var(--space-sm);
    font-weight: 700;
    font-size: 1rem;
    color: var(--clr-heading);
    flex-shrink: 0;
}

.nav-logo-icon {
    font-size: 1.3rem;
}

.nav-links {
    display: flex;
    gap: var(--space-xs);
    overflow-x: auto;
    scrollbar-width: none;
}

.nav-links::-webkit-scrollbar { display: none; }

.nav-link {
    padding: var(--space-sm) var(--space-md);
    font-size: 0.8rem;
    font-weight: 500;
    color: var(--clr-text-muted);
    border-radius: var(--radius-sm);
    white-space: nowrap;
    transition: all var(--duration-fast) var(--ease-smooth);
}

.nav-link:hover,
.nav-link.active {
    color: var(--clr-primary-light);
    background: var(--clr-primary-glow);
}

.nav-toggle {
    display: none;
    flex-direction: column;
    gap: 5px;
    background: none;
    border: none;
    cursor: pointer;
    padding: var(--space-sm);
}

.nav-toggle span {
    width: 22px;
    height: 2px;
    background: var(--clr-text);
    border-radius: 2px;
    transition: all var(--duration-normal) var(--ease-smooth);
}

/* ---------- Sections ---------- */
.section {
    position: relative;
    z-index: 1;
    padding: var(--space-4xl) var(--space-xl);
}

.section-container {
    max-width: 1100px;
    margin: 0 auto;
}

.section-header {
    text-align: center;
    margin-bottom: var(--space-3xl);
}

.section-tag {
    display: inline-block;
    padding: var(--space-xs) var(--space-md);
    font-size: 0.75rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.15em;
    color: var(--clr-primary-light);
    background: var(--clr-primary-glow);
    border: 1px solid rgba(11, 110, 79, 0.2);
    border-radius: var(--radius-full);
    margin-bottom: var(--space-md);
}

.section-title {
    font-size: clamp(1.75rem, 4vw, 2.5rem);
    font-weight: 800;
    color: var(--clr-heading);
    margin-bottom: var(--space-md);
}

.section-desc {
    font-size: 1.05rem;
    color: var(--clr-text-muted);
    max-width: 650px;
    margin: 0 auto;
}

/* ---------- Flow Diagram ---------- */
.flow-diagram {
    display: flex;
    align-items: center;
    justify-content: center;
    flex-wrap: wrap;
    gap: var(--space-md);
    padding: var(--space-2xl);
    background: var(--clr-bg-card);
    border: 1px solid var(--clr-glass-border);
    border-radius: var(--radius-lg);
    margin-bottom: var(--space-3xl);
    backdrop-filter: blur(8px);
}

.flow-item {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: var(--space-xs);
    padding: var(--space-md);
    background: var(--clr-glass);
    border: 1px solid var(--clr-glass-border);
    border-radius: var(--radius-md);
    min-width: 100px;
    transition: all var(--duration-normal) var(--ease-smooth);
}

.flow-item:hover {
    background: var(--clr-primary-glow);
    border-color: rgba(11, 110, 79, 0.3);
    transform: translateY(-4px);
}

.flow-icon {
    font-size: 1.5rem;
}

.flow-label {
    font-size: 0.75rem;
    font-weight: 600;
    color: var(--clr-heading);
    text-align: center;
}

.flow-time {
    font-size: 0.65rem;
    color: var(--clr-text-dim);
    font-family: var(--font-mono);
}

.flow-arrow {
    font-size: 1.2rem;
    color: var(--clr-text-dim);
    font-weight: 300;
}

/* ---------- Info Grid ---------- */
.info-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: var(--space-lg);
}

.info-card {
    padding: var(--space-xl);
    background: var(--clr-bg-card);
    border: 1px solid var(--clr-glass-border);
    border-radius: var(--radius-lg);
    transition: all var(--duration-normal) var(--ease-smooth);
    backdrop-filter: blur(8px);
}

.info-card:hover {
    background: var(--clr-bg-card-hover);
    border-color: rgba(11, 110, 79, 0.2);
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
}

.info-card-icon {
    font-size: 2rem;
    margin-bottom: var(--space-md);
}

.info-card h3 {
    font-size: 1.1rem;
    font-weight: 700;
    color: var(--clr-heading);
    margin-bottom: var(--space-sm);
}

.info-card p {
    font-size: 0.9rem;
    color: var(--clr-text-muted);
    line-height: 1.6;
}

.task-example {
    font-family: var(--font-mono);
    font-size: 0.8rem !important;
    padding: var(--space-md);
    background: rgba(11, 110, 79, 0.1);
    border-radius: var(--radius-sm);
    border-left: 3px solid var(--clr-primary-light);
    color: var(--clr-text) !important;
}

.warning-card {
    border-color: rgba(245, 158, 11, 0.3) !important;
    background: rgba(245, 158, 11, 0.05) !important;
}

/* ---------- Step Sections ---------- */
.step-section {
    border-top: 1px solid var(--clr-border);
}

.step-header {
    display: flex;
    gap: var(--space-xl);
    align-items: flex-start;
    margin-bottom: var(--space-2xl);
}

.step-number {
    font-size: 4rem;
    font-weight: 900;
    color: var(--clr-primary);
    opacity: 0.3;
    line-height: 1;
    font-family: var(--font-mono);
    flex-shrink: 0;
}

.step-meta {
    flex: 1;
}

.step-tag {
    display: inline-block;
    padding: var(--space-xs) var(--space-md);
    font-size: 0.7rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.15em;
    color: var(--clr-accent);
    background: rgba(240, 165, 0, 0.1);
    border: 1px solid rgba(240, 165, 0, 0.2);
    border-radius: var(--radius-full);
    margin-bottom: var(--space-sm);
}

.step-title {
    font-size: clamp(1.5rem, 3.5vw, 2rem);
    font-weight: 800;
    color: var(--clr-heading);
    margin-bottom: var(--space-sm);
}

.step-desc {
    font-size: 1rem;
    color: var(--clr-text-muted);
}

.step-content {
    display: flex;
    flex-direction: column;
    gap: var(--space-2xl);
}

/* ---------- Instruction List ---------- */
.instruction-list {
    display: flex;
    flex-direction: column;
    gap: var(--space-lg);
}

.instruction-item {
    display: flex;
    gap: var(--space-lg);
    padding: var(--space-lg);
    background: var(--clr-bg-card);
    border: 1px solid var(--clr-glass-border);
    border-radius: var(--radius-md);
    transition: all var(--duration-normal) var(--ease-smooth);
}

.instruction-item:hover {
    background: var(--clr-bg-card-hover);
    border-color: rgba(11, 110, 79, 0.15);
}

.highlight-item {
    border-color: rgba(240, 165, 0, 0.3);
    background: rgba(240, 165, 0, 0.03);
}

.instruction-num {
    width: 36px;
    height: 36px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: linear-gradient(135deg, var(--clr-primary), var(--clr-primary-dark));
    color: white;
    font-weight: 700;
    font-size: 0.9rem;
    border-radius: 50%;
    flex-shrink: 0;
}

.instruction-text {
    flex: 1;
    min-width: 0;
}

.instruction-text h4 {
    font-size: 1rem;
    font-weight: 700;
    color: var(--clr-heading);
    margin-bottom: var(--space-xs);
}

.instruction-text p {
    font-size: 0.9rem;
    color: var(--clr-text-muted);
}

.detail-list {
    margin-top: var(--space-sm);
    padding-left: var(--space-lg);
    display: flex;
    flex-direction: column;
    gap: var(--space-xs);
}

.detail-list li {
    font-size: 0.9rem;
    color: var(--clr-text-muted);
}

/* ---------- Copy Box ---------- */
.copy-box {
    margin-top: var(--space-md);
    padding: var(--space-md) var(--space-lg);
    background: rgba(11, 110, 79, 0.08);
    border: 1px dashed rgba(11, 110, 79, 0.3);
    border-radius: var(--radius-sm);
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    gap: var(--space-md);
}

.copy-box span {
    font-family: var(--font-mono);
    font-size: 0.85rem;
    color: var(--clr-primary-light);
    white-space: pre-wrap;
    word-break: break-word;
    flex: 1;
}

.copy-btn {
    padding: var(--space-xs) var(--space-md);
    background: var(--clr-primary);
    color: white;
    border: none;
    border-radius: var(--radius-sm);
    font-size: 0.75rem;
    font-weight: 600;
    cursor: pointer;
    white-space: nowrap;
    transition: all var(--duration-fast) var(--ease-smooth);
    flex-shrink: 0;
}

.copy-btn:hover {
    background: var(--clr-primary-light);
    transform: scale(1.05);
}

.copy-btn.copied {
    background: var(--clr-success);
}

/* ---------- Folder Path ---------- */
.folder-path {
    display: flex;
    align-items: center;
    gap: var(--space-sm);
    padding: var(--space-md);
    background: rgba(59, 130, 246, 0.08);
    border: 1px solid rgba(59, 130, 246, 0.2);
    border-radius: var(--radius-sm);
    font-family: var(--font-mono);
    font-size: 0.85rem;
    color: var(--clr-info);
    margin-top: var(--space-sm);
}

.folder-icon {
    font-size: 1.2rem;
}

/* ---------- Tip & Warning Boxes ---------- */
.tip-box, .warning-box {
    display: flex;
    gap: var(--space-lg);
    padding: var(--space-lg);
    border-radius: var(--radius-md);
}

.tip-box {
    background: rgba(34, 197, 94, 0.06);
    border: 1px solid rgba(34, 197, 94, 0.2);
}

.warning-box {
    background: rgba(239, 68, 68, 0.06);
    border: 1px solid rgba(239, 68, 68, 0.2);
}

.tip-icon, .warning-icon {
    font-size: 1.5rem;
    flex-shrink: 0;
}

.tip-content h4, .warning-content h4 {
    font-size: 0.95rem;
    font-weight: 700;
    margin-bottom: var(--space-xs);
}

.tip-content h4 { color: var(--clr-success); }
.warning-content h4 { color: var(--clr-danger); }

.tip-content p, .warning-content p {
    font-size: 0.9rem;
    color: var(--clr-text-muted);
}

/* ---------- Screenshot Gallery ---------- */
.screenshot-gallery {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
    gap: var(--space-lg);
}

.screenshot-card {
    position: relative;
    border-radius: var(--radius-md);
    overflow: hidden;
    border: 1px solid var(--clr-glass-border);
    background: var(--clr-surface);
    cursor: pointer;
    transition: all var(--duration-normal) var(--ease-smooth);
}

.screenshot-card:hover {
    transform: translateY(-6px);
    border-color: rgba(11, 110, 79, 0.3);
    box-shadow: var(--shadow-lg), var(--shadow-glow);
}

.screenshot-card img {
    width: 100%;
    height: 260px;
    object-fit: cover;
    object-position: top;
    transition: transform var(--duration-slow) var(--ease-smooth);
}

.screenshot-card:hover img {
    transform: scale(1.05);
}

.screenshot-caption {
    padding: var(--space-md) var(--space-lg);
    font-size: 0.8rem;
    color: var(--clr-text-muted);
    background: var(--clr-surface);
    border-top: 1px solid var(--clr-border);
}

/* ---------- Timeline ---------- */
.timeline {
    position: relative;
    max-width: 700px;
    margin: 0 auto;
}

.timeline::before {
    content: '';
    position: absolute;
    left: 120px;
    top: 0;
    bottom: 0;
    width: 2px;
    background: linear-gradient(to bottom, var(--clr-primary), var(--clr-accent), var(--clr-primary));
    opacity: 0.3;
}

.timeline-item {
    display: flex;
    align-items: flex-start;
    gap: var(--space-xl);
    padding: var(--space-lg) 0;
    position: relative;
}

.timeline-time {
    width: 100px;
    font-size: 0.75rem;
    font-weight: 600;
    color: var(--clr-text-dim);
    text-align: right;
    flex-shrink: 0;
    font-family: var(--font-mono);
    padding-top: 2px;
}

.timeline-dot {
    width: 14px;
    height: 14px;
    border-radius: 50%;
    background: var(--clr-primary);
    border: 3px solid var(--clr-bg);
    box-shadow: 0 0 0 2px var(--clr-primary);
    flex-shrink: 0;
    margin-top: 4px;
    position: relative;
    z-index: 1;
}

.dot-work { background: var(--clr-info); box-shadow: 0 0 0 2px var(--clr-info); }
.dot-break { background: var(--clr-warning); box-shadow: 0 0 0 2px var(--clr-warning); }
.dot-checkout { background: var(--clr-danger); box-shadow: 0 0 0 2px var(--clr-danger); }

.timeline-content {
    flex: 1;
    min-width: 0;
}

.timeline-content h4 {
    font-size: 1rem;
    font-weight: 700;
    color: var(--clr-heading);
    margin-bottom: var(--space-xs);
}

.timeline-content p {
    font-size: 0.85rem;
    color: var(--clr-text-muted);
}

/* ---------- Footer ---------- */
.footer {
    position: relative;
    z-index: 1;
    padding: var(--space-3xl) var(--space-xl);
    border-top: 1px solid var(--clr-border);
    text-align: center;
}

.footer-content {
    max-width: 600px;
    margin: 0 auto;
}

.footer-logo {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: var(--space-sm);
    font-size: 1.1rem;
    font-weight: 700;
    color: var(--clr-heading);
    margin-bottom: var(--space-md);
}

.footer-note {
    font-size: 0.8rem;
    color: var(--clr-text-dim);
    margin-bottom: var(--space-sm);
}

.footer-credit {
    font-size: 0.75rem;
    color: var(--clr-text-dim);
    opacity: 0.6;
}

/* ---------- Lightbox ---------- */
.lightbox {
    position: fixed;
    inset: 0;
    background: rgba(0, 0, 0, 0.92);
    display: flex;
    align-items: center;
    justify-content: center;
    flex-direction: column;
    z-index: 10001;
    opacity: 0;
    visibility: hidden;
    transition: all var(--duration-normal) var(--ease-smooth);
    backdrop-filter: blur(8px);
    padding: var(--space-xl);
}

.lightbox.active {
    opacity: 1;
    visibility: visible;
}

.lightbox img {
    max-width: 90vw;
    max-height: 80vh;
    object-fit: contain;
    border-radius: var(--radius-md);
    box-shadow: var(--shadow-lg);
}

.lightbox-close {
    position: absolute;
    top: var(--space-xl);
    right: var(--space-xl);
    width: 44px;
    height: 44px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: rgba(255,255,255,0.1);
    border: none;
    border-radius: 50%;
    color: white;
    font-size: 1.5rem;
    cursor: pointer;
    transition: all var(--duration-fast) var(--ease-smooth);
}

.lightbox-close:hover {
    background: rgba(255,255,255,0.2);
    transform: scale(1.1);
}

.lightbox-caption {
    margin-top: var(--space-md);
    font-size: 0.9rem;
    color: rgba(255,255,255,0.7);
    text-align: center;
}

/* ---------- Back to Top ---------- */
.back-to-top {
    position: fixed;
    bottom: var(--space-xl);
    right: var(--space-xl);
    width: 48px;
    height: 48px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--clr-primary);
    color: white;
    border: none;
    border-radius: 50%;
    cursor: pointer;
    z-index: 100;
    opacity: 0;
    visibility: hidden;
    transform: translateY(20px);
    transition: all var(--duration-normal) var(--ease-smooth);
    box-shadow: 0 4px 16px rgba(11, 110, 79, 0.4);
}

.back-to-top.visible {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
}

.back-to-top:hover {
    background: var(--clr-primary-light);
    transform: translateY(-3px);
}

/* ---------- Animations ---------- */
@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(30px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.animate-in {
    opacity: 0;
    transform: translateY(30px);
    transition: opacity 0.6s var(--ease-smooth), transform 0.6s var(--ease-smooth);
}

.animate-in.visible {
    opacity: 1;
    transform: translateY(0);
}

/* ---------- Responsive ---------- */
@media (max-width: 768px) {
    html { font-size: 15px; }
    
    .section { padding: var(--space-2xl) var(--space-md); }
    
    .hero { padding: var(--space-xl); }
    
    .hero-stats { gap: var(--space-xl); }
    
    .step-header {
        flex-direction: column;
        gap: var(--space-md);
    }
    
    .step-number {
        font-size: 2.5rem;
    }
    
    .flow-diagram {
        padding: var(--space-lg);
    }
    
    .flow-arrow { display: none; }
    
    .flow-diagram {
        display: grid;
        grid-template-columns: repeat(2, 1fr);
    }
    
    .instruction-item {
        flex-direction: column;
        gap: var(--space-md);
    }
    
    .screenshot-gallery {
        grid-template-columns: 1fr;
    }
    
    .screenshot-card img {
        height: 220px;
    }
    
    .nav-links {
        display: none;
        position: absolute;
        top: 60px;
        left: 0;
        right: 0;
        background: rgba(10, 14, 23, 0.95);
        backdrop-filter: blur(16px);
        flex-direction: column;
        padding: var(--space-md);
        border-bottom: 1px solid var(--clr-border);
    }
    
    .nav-links.open { display: flex; }
    
    .nav-toggle { display: flex; }
    
    .timeline::before { left: 20px; }
    
    .timeline-time {
        width: auto;
        font-size: 0.65rem;
    }
    
    .timeline-item {
        flex-direction: column;
        padding-left: 40px;
        gap: var(--space-sm);
    }
    
    .timeline-dot {
        position: absolute;
        left: 14px;
        top: var(--space-lg);
    }
    
    .copy-box {
        flex-direction: column;
    }
}

@media (max-width: 480px) {
    .flow-diagram {
        grid-template-columns: 1fr;
    }
    
    .hero-stats {
        flex-direction: column;
        gap: var(--space-lg);
    }
    
    .info-grid {
        grid-template-columns: 1fr;
    }
}