:root {
  /* Color Palette - Editorial Dark Theme (Default) */
  --bg-primary: #0a0e17;
  --bg-secondary: #111726;
  --bg-card: rgba(18, 24, 40, 0.75);
  --bg-card-hover: rgba(26, 35, 58, 0.85);
  --bg-glass: rgba(14, 20, 34, 0.8);
  --border-subtle: rgba(255, 255, 255, 0.08);
  --border-accent: rgba(56, 189, 248, 0.3);
  
  --text-primary: #f8fafc;
  --text-secondary: #cbd5e1;
  --text-muted: #94a3b8;
  --text-accent: #38bdf8;
  
  --accent-cyan: #38bdf8;
  --accent-blue: #3b82f6;
  --accent-indigo: #6366f1;
  --accent-gold: #f59e0b;
  --accent-emerald: #10b981;
  --accent-rose: #f43f5e;
  
  --glow-cyan: rgba(56, 189, 248, 0.15);
  --glow-gold: rgba(245, 158, 11, 0.15);
  --glow-blue: rgba(59, 130, 246, 0.15);

  /* Typography */
  --font-serif: 'Playfair Display', Georgia, serif;
  --font-sans: 'Plus Jakarta Sans', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  --font-mono: 'Space Grotesk', 'JetBrains Mono', monospace;

  /* Sizing & Spacing */
  --text-base: 18px; /* Đảm bảo tối thiểu 16px */
  --text-infographic: 18px; /* Tối thiểu 18px cho infographic */
  --max-width-read: 760px;
  --max-width-wide: 1120px;
  --header-height: 64px;
  --radius-lg: 18px;
  --radius-md: 12px;
  --radius-sm: 8px;
  --transition-smooth: all 0.35s cubic-bezier(0.16, 1, 0.3, 1);
}

/* Light Theme Variables */
[data-theme="light"] {
  --bg-primary: #f8fafc;
  --bg-secondary: #f1f5f9;
  --bg-card: rgba(255, 255, 255, 0.92);
  --bg-card-hover: rgba(255, 255, 255, 1);
  --bg-glass: rgba(255, 255, 255, 0.88);
  --border-subtle: rgba(15, 23, 42, 0.1);
  --border-accent: rgba(2, 132, 199, 0.35);
  
  --text-primary: #0f172a;
  --text-secondary: #334155;
  --text-muted: #64748b;
  --text-accent: #0284c7;
  
  --accent-cyan: #0284c7;
  --accent-blue: #2563eb;
  --accent-indigo: #4f46e5;
  --accent-gold: #d97706;
  --accent-emerald: #059669;
  --accent-rose: #e11d48;
  
  --glow-cyan: rgba(2, 132, 199, 0.08);
  --glow-gold: rgba(217, 119, 6, 0.08);
  --glow-blue: rgba(37, 99, 235, 0.08);
}

/* Reset & Global Standards */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  scroll-behavior: smooth;
  font-size: 18px; /* Tiêu chuẩn đọc tối thiểu 16px */
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

body {
  font-family: var(--font-sans);
  background-color: var(--bg-primary);
  color: var(--text-secondary);
  line-height: 1.85;
  letter-spacing: -0.01em;
  overflow-x: hidden;
  transition: background-color 0.4s ease, color 0.4s ease;
}

/* Progress bar */
#reading-progress-container {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 4px;
  background: rgba(255, 255, 255, 0.05);
  z-index: 1000;
}

#reading-progress-bar {
  height: 100%;
  width: 0%;
  background: linear-gradient(90deg, var(--accent-cyan), var(--accent-blue), var(--accent-gold));
  transition: width 0.1s ease-out;
  box-shadow: 0 0 10px var(--accent-cyan);
}

/* Header bar */
.top-nav {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: var(--header-height);
  background: var(--bg-glass);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border-bottom: 1px solid var(--border-subtle);
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 2rem;
  z-index: 999;
  transition: var(--transition-smooth);
}

.brand-badge {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  font-family: var(--font-mono);
  font-size: 0.9rem;
  font-weight: 700;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--text-accent);
}

.brand-dot {
  width: 8px;
  height: 8px;
  background-color: var(--accent-cyan);
  border-radius: 50%;
  box-shadow: 0 0 8px var(--accent-cyan);
  animation: pulse-dot 2.2s infinite;
}

@keyframes pulse-dot {
  0%, 100% { opacity: 1; transform: scale(1); }
  50% { opacity: 0.5; transform: scale(1.3); }
}

.nav-actions {
  display: flex;
  align-items: center;
  gap: 1.25rem;
}

.theme-toggle-btn {
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  color: var(--text-primary);
  width: 40px;
  height: 40px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  transition: var(--transition-smooth);
  font-size: 1.15rem;
}

.theme-toggle-btn:hover {
  background: var(--bg-card-hover);
  border-color: var(--border-accent);
  transform: translateY(-1px);
}

/* Hero Section */
.hero-header {
  position: relative;
  min-height: 94vh;
  display: flex;
  align-items: flex-end;
  padding: 8rem 2rem 5rem;
  background: radial-gradient(circle at 50% 20%, rgba(56, 189, 248, 0.08), transparent 70%);
  overflow: hidden;
}

.hero-bg-media {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  z-index: 1;
}

.hero-image {
  width: 100%;
  height: 100%;
  object-fit: cover;
  object-position: center;
  filter: brightness(0.68) contrast(1.05);
  transform: scale(1.02);
  transition: transform 0.5s ease-out;
}

[data-theme="light"] .hero-image {
  filter: brightness(0.78) contrast(1.02);
}

.hero-gradient-overlay {
  position: absolute;
  inset: 0;
  background: linear-gradient(
    180deg,
    rgba(10, 14, 23, 0.3) 0%,
    rgba(10, 14, 23, 0.6) 45%,
    var(--bg-primary) 98%
  );
  z-index: 2;
}

[data-theme="light"] .hero-gradient-overlay {
  background: linear-gradient(
    180deg,
    rgba(15, 23, 42, 0.35) 0%,
    rgba(248, 250, 252, 0.7) 50%,
    var(--bg-primary) 98%
  );
}

.hero-content {
  position: relative;
  z-index: 3;
  max-width: var(--max-width-wide);
  margin: 0 auto;
  width: 100%;
}

.hero-tag {
  display: inline-flex;
  align-items: center;
  gap: 0.6rem;
  padding: 0.45rem 1.1rem;
  background: rgba(56, 189, 248, 0.12);
  border: 1px solid var(--border-accent);
  border-radius: 999px;
  font-family: var(--font-mono);
  font-size: 0.95rem;
  font-weight: 600;
  color: var(--accent-cyan);
  text-transform: uppercase;
  letter-spacing: 0.06em;
  margin-bottom: 1.5rem;
  backdrop-filter: blur(8px);
}

.hero-title {
  font-family: var(--font-serif);
  font-size: clamp(2.35rem, 5vw, 4.25rem);
  font-weight: 800;
  line-height: 1.18;
  color: var(--text-primary);
  margin-bottom: 2rem;
  text-wrap: balance;
  text-shadow: 0 4px 20px rgba(0, 0, 0, 0.5);
}

.hero-sapo {
  font-size: clamp(1.2rem, 2vw, 1.45rem);
  line-height: 1.68;
  color: var(--text-primary);
  font-weight: 500;
  max-width: 860px;
  margin-bottom: 2.5rem;
  border-left: 3px solid var(--accent-cyan);
  padding-left: 1.5rem;
  background: rgba(10, 14, 23, 0.45);
  backdrop-filter: blur(10px);
  border-radius: 0 var(--radius-md) var(--radius-md) 0;
  padding-top: 0.5rem;
  padding-bottom: 0.5rem;
}

[data-theme="light"] .hero-sapo {
  background: rgba(255, 255, 255, 0.85);
  color: #0f172a;
  border-left-color: var(--accent-cyan);
}

.hero-meta-bar {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 2rem;
  font-family: var(--font-mono);
  font-size: 0.95rem;
  color: var(--text-muted);
  border-top: 1px solid var(--border-subtle);
  padding-top: 1.5rem;
}

.meta-item {
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.meta-item strong {
  color: var(--text-primary);
  font-weight: 600;
}

/* Article Container */
.article-body {
  position: relative;
  max-width: var(--max-width-wide);
  margin: 0 auto;
  padding: 4rem 1.5rem 6rem;
}

.reading-column {
  max-width: var(--max-width-read);
  margin: 0 auto;
}

/* Typography for Article Content */
.reading-column p {
  font-size: 1.15rem; /* 20.7px - Rõ ràng, dễ đọc, chuẩn tối thiểu 16px */
  line-height: 1.9;
  color: var(--text-secondary);
  margin-bottom: 1.75rem;
  font-weight: 400;
}

.reading-column p strong {
  color: var(--text-primary);
  font-weight: 600;
}

/* Drop cap for first paragraph */
.dropcap-p::first-letter {
  font-family: var(--font-serif);
  font-size: 4.8rem;
  float: left;
  line-height: 0.82;
  margin-right: 0.85rem;
  margin-top: 0.35rem;
  color: var(--accent-cyan);
  font-weight: 800;
}

/* Section Structure */
.article-section {
  margin-bottom: 5.5rem;
  position: relative;
}

.section-header-block {
  margin: 5rem 0 2.5rem;
  position: relative;
}

.section-num {
  font-family: var(--font-mono);
  font-size: 1.05rem;
  font-weight: 700;
  color: var(--accent-cyan);
  letter-spacing: 0.15em;
  text-transform: uppercase;
  margin-bottom: 0.6rem;
  display: flex;
  align-items: center;
  gap: 0.75rem;
}

.section-num::after {
  content: "";
  height: 1px;
  flex: 1;
  max-width: 120px;
  background: linear-gradient(90deg, var(--accent-cyan), transparent);
}

.section-title {
  font-family: var(--font-serif);
  font-size: clamp(2rem, 3.5vw, 2.75rem);
  font-weight: 700;
  line-height: 1.25;
  color: var(--text-primary);
  letter-spacing: -0.02em;
}

/* Editorial Quotes / Voice of Citizens */
.citizen-quote-card {
  margin: 2.8rem 0;
  padding: 1.8rem 2rem;
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-left: 4px solid var(--accent-blue);
  border-radius: var(--radius-md);
  box-shadow: 0 10px 30px rgba(0, 0, 0, 0.15);
  position: relative;
  transition: var(--transition-smooth);
}

.citizen-quote-card:hover {
  transform: translateY(-2px);
  border-left-color: var(--accent-cyan);
  border-color: var(--border-accent);
}

.quote-icon {
  position: absolute;
  top: 1.2rem;
  right: 1.5rem;
  font-family: var(--font-serif);
  font-size: 3.5rem;
  line-height: 1;
  color: var(--border-accent);
  opacity: 0.4;
  pointer-events: none;
}

.citizen-quote-card p {
  font-size: 1.15rem;
  line-height: 1.85;
  color: var(--text-primary);
  font-style: normal;
  margin-bottom: 1rem;
}

.citizen-speaker {
  font-family: var(--font-mono);
  font-size: 0.95rem;
  font-weight: 600;
  color: var(--accent-cyan);
  text-transform: uppercase;
  letter-spacing: 0.04em;
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.citizen-speaker::before {
  content: "—";
  color: var(--text-muted);
}

/* ==========================================================
   INFOGRAPHIC CONTAINERS & VISUALIZATIONS
   YÊU CẦU ĐẶC BIỆT: Cỡ chữ tại infographic tối thiểu 18px!
   ========================================================== */
.infographic-wrapper {
  margin: 3.5rem 0 4rem;
  width: 100%;
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-lg);
  padding: 2.25rem 2rem;
  box-shadow: 0 16px 40px -10px rgba(0, 0, 0, 0.35);
  position: relative;
  overflow: hidden;
  backdrop-filter: blur(12px);
}

.infographic-wrapper::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 3px;
  background: linear-gradient(90deg, var(--accent-cyan), var(--accent-blue), var(--accent-gold));
}

.infographic-header {
  margin-bottom: 2rem;
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

.infographic-badge {
  font-family: var(--font-mono);
  font-size: 18px; /* Đảm bảo tối thiểu 18px */
  font-weight: 700;
  color: var(--accent-cyan);
  text-transform: uppercase;
  letter-spacing: 0.08em;
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.infographic-title {
  font-family: var(--font-serif);
  font-size: 24px; /* Tối thiểu 18px */
  font-weight: 700;
  color: var(--text-primary);
  line-height: 1.35;
}

.infographic-subtitle {
  font-size: 18px; /* Tối thiểu 18px */
  color: var(--text-muted);
  line-height: 1.5;
}

/* Common Metric Box styles */
.metric-grid-3 {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 1.25rem;
  margin-bottom: 2rem;
}

.metric-grid-2 {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 1.5rem;
  margin-bottom: 2rem;
}

.metric-card {
  background: var(--bg-secondary);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  padding: 1.5rem;
  text-align: center;
  transition: var(--transition-smooth);
}

.metric-card:hover {
  border-color: var(--border-accent);
  background: var(--bg-card-hover);
  transform: translateY(-2px);
}

.metric-value-huge {
  font-family: var(--font-mono);
  font-size: 48px; /* Cỡ lớn nổi bật */
  font-weight: 800;
  line-height: 1.1;
  color: var(--accent-cyan);
  margin-bottom: 0.5rem;
}

.metric-value-huge.gold {
  color: var(--accent-gold);
}

.metric-value-huge.emerald {
  color: var(--accent-emerald);
}

.metric-label {
  font-size: 18px; /* Tối thiểu 18px */
  font-weight: 600;
  color: var(--text-primary);
  line-height: 1.45;
  margin-bottom: 0.25rem;
}

.metric-desc {
  font-size: 18px; /* Tối thiểu 18px */
  color: var(--text-muted);
  line-height: 1.4;
}

/* ==========================================================
   INFOGRAPHIC 1: Phường Ngọc Hà & Dự án 7,2ha Vĩnh Phúc
   ========================================================== */
.diagram-container {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 2rem;
  align-items: center;
}

.donut-vis-box {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  position: relative;
}

.svg-donut {
  width: 240px;
  height: 240px;
  transform: rotate(-90deg);
}

.donut-bg {
  fill: none;
  stroke: var(--border-subtle);
  stroke-width: 24;
}

.donut-segment-1 {
  fill: none;
  stroke: var(--accent-blue);
  stroke-width: 24;
  stroke-dasharray: 260 565;
  stroke-dashoffset: 0;
  transition: stroke-dasharray 1.5s ease-out;
}

.donut-segment-2 {
  fill: none;
  stroke: var(--accent-cyan);
  stroke-width: 24;
  stroke-dasharray: 290 565;
  stroke-dashoffset: -260;
  transition: stroke-dasharray 1.5s ease-out;
}

.donut-center-text {
  position: absolute;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
}

.donut-center-num {
  font-family: var(--font-mono);
  font-size: 42px;
  font-weight: 800;
  color: var(--text-primary);
}

.donut-center-label {
  font-size: 18px; /* Tối thiểu 18px */
  color: var(--text-muted);
  font-weight: 500;
}

.interactive-flow-col {
  display: flex;
  flex-direction: column;
  gap: 1.25rem;
}

.flow-step-item {
  display: flex;
  align-items: flex-start;
  gap: 1.25rem;
  background: var(--bg-secondary);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  padding: 1.25rem;
  transition: var(--transition-smooth);
}

.flow-step-item:hover {
  border-color: var(--border-accent);
}

.flow-step-icon {
  width: 48px;
  height: 48px;
  border-radius: 10px;
  background: rgba(56, 189, 248, 0.15);
  color: var(--accent-cyan);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 24px;
  flex-shrink: 0;
}

.flow-step-content h4 {
  font-size: 19px; /* Tối thiểu 18px */
  color: var(--text-primary);
  font-weight: 700;
  margin-bottom: 0.3rem;
}

.flow-step-content p {
  font-size: 18px; /* Tối thiểu 18px */
  color: var(--text-secondary);
  line-height: 1.45;
  margin-bottom: 0;
}

/* ==========================================================
   INFOGRAPHIC 2: Bộ máy thực thi & Chỉ số HanoiWork
   ========================================================== */
.admin-coverage-bar-group {
  display: flex;
  flex-direction: column;
  gap: 1.25rem;
  margin-bottom: 2.25rem;
}

.coverage-row {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

.coverage-meta {
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.coverage-label {
  font-size: 19px; /* Tối thiểu 18px */
  font-weight: 600;
  color: var(--text-primary);
}

.coverage-fraction {
  font-family: var(--font-mono);
  font-size: 20px; /* Tối thiểu 18px */
  font-weight: 700;
  color: var(--accent-cyan);
}

.bar-track {
  height: 14px;
  background: var(--bg-secondary);
  border-radius: 999px;
  overflow: hidden;
  border: 1px solid var(--border-subtle);
}

.bar-fill {
  height: 100%;
  width: 0%;
  border-radius: 999px;
  background: linear-gradient(90deg, var(--accent-blue), var(--accent-cyan));
  transition: width 1.4s cubic-bezier(0.16, 1, 0.3, 1);
}

.bar-fill.gold {
  background: linear-gradient(90deg, var(--accent-gold), #fbbf24);
}

.tasks-split-container {
  background: var(--bg-secondary);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  padding: 1.75rem;
  margin-bottom: 2rem;
}

.tasks-split-header {
  display: flex;
  justify-content: space-between;
  align-items: flex-end;
  margin-bottom: 1rem;
}

.tasks-split-title {
  font-size: 19px; /* Tối thiểu 18px */
  font-weight: 700;
  color: var(--text-primary);
}

.tasks-split-total {
  font-family: var(--font-mono);
  font-size: 22px; /* Tối thiểu 18px */
  font-weight: 700;
  color: var(--accent-gold);
}

.dual-progress-bar {
  display: flex;
  height: 20px;
  border-radius: 999px;
  overflow: hidden;
  margin-bottom: 1.25rem;
}

.dual-segment-completed {
  width: 0%;
  background: var(--accent-emerald);
  transition: width 1.2s ease-out;
}

.dual-segment-pending {
  width: 0%;
  background: var(--accent-blue);
  transition: width 1.2s ease-out;
}

.dual-legend {
  display: flex;
  flex-wrap: wrap;
  gap: 2rem;
  justify-content: space-between;
}

.legend-item {
  display: flex;
  align-items: center;
  gap: 0.75rem;
}

.legend-badge {
  width: 14px;
  height: 14px;
  border-radius: 3px;
}

.legend-badge.emerald { background: var(--accent-emerald); }
.legend-badge.blue { background: var(--accent-blue); }

.legend-text {
  font-size: 18px; /* Tối thiểu 18px */
  color: var(--text-secondary);
}

.legend-number {
  font-family: var(--font-mono);
  font-weight: 700;
  font-size: 19px; /* Tối thiểu 18px */
  color: var(--text-primary);
}

/* ==========================================================
   INFOGRAPHIC 3: 13 Nguồn dữ liệu ưu tiên & Hệ thống số
   ========================================================== */
.data-sources-list {
  display: flex;
  flex-direction: column;
  gap: 1.25rem;
  margin-bottom: 2rem;
}

.data-source-row {
  background: var(--bg-secondary);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  padding: 1.25rem 1.5rem;
  display: flex;
  flex-direction: column;
  gap: 0.6rem;
  transition: var(--transition-smooth);
}

.data-source-row:hover {
  border-color: var(--border-accent);
}

.ds-meta {
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.ds-name {
  font-size: 19px; /* Tối thiểu 18px */
  font-weight: 600;
  color: var(--text-primary);
}

.ds-percent {
  font-family: var(--font-mono);
  font-size: 22px; /* Tối thiểu 18px */
  font-weight: 800;
}

.ds-percent.c100 { color: var(--accent-emerald); }
.ds-percent.c97 { color: var(--accent-cyan); }
.ds-percent.c70 { color: var(--accent-blue); }
.ds-percent.c50 { color: var(--accent-gold); }

.ds-details {
  font-size: 18px; /* Tối thiểu 18px */
  color: var(--text-muted);
  line-height: 1.4;
}

.platforms-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 1rem;
  margin-top: 1.75rem;
}

.platform-pill {
  background: rgba(56, 189, 248, 0.08);
  border: 1px solid var(--border-accent);
  border-radius: var(--radius-md);
  padding: 1rem;
  text-align: center;
  font-family: var(--font-mono);
  font-size: 18px; /* Tối thiểu 18px */
  font-weight: 700;
  color: var(--text-primary);
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
}

/* Editorial In-between Image */
.editorial-photo-box {
  margin: 3.5rem 0;
  border-radius: var(--radius-lg);
  overflow: hidden;
  border: 1px solid var(--border-subtle);
  background: var(--bg-card);
}

.editorial-img {
  width: 100%;
  height: 440px;
  object-fit: cover;
  display: block;
  filter: brightness(0.9);
}

.editorial-caption {
  padding: 1rem 1.5rem;
  font-size: 18px; /* Tối thiểu 18px */
  color: var(--text-muted);
  font-style: italic;
  border-top: 1px solid var(--border-subtle);
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

/* Author Signature & Article Footer */
.author-signature-block {
  margin: 4.5rem 0 3rem;
  padding: 2.5rem 0;
  border-top: 1px solid var(--border-subtle);
  border-bottom: 1px solid var(--border-subtle);
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 1.5rem;
}

.author-name-tag {
  font-family: var(--font-serif);
  font-size: 26px;
  font-weight: 700;
  color: var(--text-primary);
}

.author-role {
  font-size: 18px;
  color: var(--text-muted);
  font-family: var(--font-mono);
}

.article-document-stamp {
  font-family: var(--font-mono);
  font-size: 18px;
  color: var(--accent-cyan);
  background: rgba(56, 189, 248, 0.08);
  padding: 0.6rem 1.2rem;
  border-radius: var(--radius-sm);
  border: 1px solid var(--border-accent);
}

/* Footer */
.site-footer {
  background: var(--bg-secondary);
  border-top: 1px solid var(--border-subtle);
  padding: 3rem 2rem;
  text-align: center;
  font-size: 18px;
  color: var(--text-muted);
}

/* Animations & Scroll Trigger Classes */
.animate-on-scroll {
  opacity: 0;
  transform: translateY(28px);
  transition: opacity 0.8s cubic-bezier(0.16, 1, 0.3, 1), transform 0.8s cubic-bezier(0.16, 1, 0.3, 1);
}

.animate-on-scroll.is-visible {
  opacity: 1;
  transform: translateY(0);
}

/* Responsive adjustments */
@media (max-width: 900px) {
  html {
    font-size: 17px;
  }
  
  .diagram-container {
    grid-template-columns: 1fr;
  }
  
  .hero-header {
    min-height: 85vh;
    padding-top: 6rem;
  }
  
  .author-signature-block {
    flex-direction: column;
    align-items: flex-start;
  }
}

@media (max-width: 640px) {
  html {
    font-size: 16px; /* Luôn đảm bảo tối thiểu 16px toàn trang */
  }

  .top-nav {
    padding: 0 1rem;
  }

  .article-body {
    padding: 2.5rem 1rem 4rem;
  }

  .hero-header {
    padding: 6rem 1rem 3.5rem;
  }

  .infographic-wrapper {
    padding: 1.5rem 1rem;
  }

  .metric-value-huge {
    font-size: 38px;
  }

  .dual-legend {
    flex-direction: column;
    gap: 0.75rem;
  }
}