/* ==========================================================================
   DESIGN SYSTEM & VARIABLES (Harvard Business School / Tri AI Consulting Style)
   ========================================================================== */

:root {
  --color-bg-dark: #111111;
  --color-bg-light: #faf9f6; /* Warm HBS cream background */
  --color-bg-white: #ffffff;
  
  --color-primary: #e10600; /* Harvard Crimson Red */
  --color-primary-rgb: 225, 6, 0;
  --color-primary-hover: #c00500;
  
  --color-accent: #e10600;
  --color-accent-hover: #c00500;
  
  --color-text-dark: #111111;
  --color-text-light: #ffffff;
  --color-text-muted: #555555;
  --color-text-muted-dark: #888888;
  
  --color-error: #ff453a;
  --color-success: #34c759;
  
  --font-sans: 'Inter', 'Noto Sans Thai', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  --font-serif: 'Lora', 'Noto Serif Thai', Georgia, Cambria, "Times New Roman", Times, serif;
  
  --transition-smooth: all 0.2s ease-in-out;
  --transition-fast: all 0.1s ease-out;
  
  --shadow-soft: none; /* Flat HBS Editorial design */
  --shadow-medium: none;
  --shadow-premium: none;
  
  --border-radius-sm: 0px; /* Sharp, authoritative HBS square corners */
  --border-radius-md: 0px;
  --border-radius-lg: 0px;
  
  --border-main: 1px solid #e5e5e5;
}

/* ==========================================================================
   BASE STYLES & RESET
   ========================================================================== */

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

html {
  font-family: var(--font-sans);
  font-size: 16px;
  scroll-behavior: smooth;
  color: var(--color-text-dark);
  background-color: var(--color-bg-white);
  -webkit-font-smoothing: antialiased;
}

body {
  line-height: 1.65;
  overflow-x: hidden;
}

h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-serif);
  font-weight: 700;
  line-height: 1.2;
  letter-spacing: -0.01em;
  color: var(--color-text-dark);
}

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

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

.container {
  width: 100%;
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 2rem;
}

.max-w-xl {
  max-width: 680px;
}

.text-center {
  text-align: center;
}

.text-gradient {
  color: var(--color-primary); /* Solid crimson instead of gradients */
  background: none;
  -webkit-background-clip: initial;
  -webkit-text-fill-color: initial;
}

.text-italic {
  font-style: italic;
}

/* ==========================================================================
   BUTTONS & ACCENTS
   ========================================================================== */

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 1.1rem 2.2rem;
  font-size: 0.9rem;
  font-weight: 700;
  border-radius: var(--border-radius-sm);
  transition: var(--transition-smooth);
  cursor: pointer;
  border: none;
  outline: none;
  letter-spacing: 0.05em;
  text-transform: uppercase;
}

.btn-primary {
  background-color: var(--color-primary);
  color: var(--color-text-light);
}

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

.btn-secondary {
  background-color: transparent;
  color: var(--color-text-dark);
  border: 1px solid var(--color-text-dark);
}

.btn-secondary:hover {
  background-color: var(--color-bg-light);
  border-color: var(--color-primary);
  color: var(--color-primary);
}

.btn-tertiary {
  background-color: transparent;
  color: var(--color-text-muted);
  font-weight: 600;
  border-bottom: 1px solid var(--color-text-muted);
  border-radius: 0;
  padding: 0.5rem 0;
  margin-left: 1.5rem;
  font-size: 0.85rem;
  letter-spacing: 0.02em;
}

.btn-tertiary:hover {
  color: var(--color-primary);
  border-bottom-color: var(--color-primary);
}

.btn-block {
  display: flex;
  width: 100%;
}

.badge {
  display: inline-block;
  padding: 0.4rem 0.8rem;
  font-size: 0.7rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.15em;
  background-color: var(--color-bg-light);
  border: 1px solid rgba(225, 6, 0, 0.25);
  color: var(--color-primary);
  border-radius: var(--border-radius-sm);
  margin-bottom: 1.5rem;
}

.sub-badge {
  display: inline-block;
  font-size: 0.8rem;
  font-weight: 700;
  text-transform: uppercase;
  color: var(--color-primary);
  letter-spacing: 0.2em;
  margin-bottom: 0.75rem;
}

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

.header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 1000;
  background-color: rgba(255, 255, 255, 0.97);
  border-bottom: var(--border-main);
  transition: var(--transition-smooth);
}

.header-container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  max-width: 1200px;
  margin: 0 auto;
  padding: 1.25rem 2rem;
}

.logo-link {
  font-family: var(--font-serif);
  font-size: 1.35rem;
  font-weight: 700;
  letter-spacing: -0.02em;
}

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

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

.logo-consulting {
  color: var(--color-text-muted);
  font-weight: 400;
}

.desktop-nav ul {
  display: flex;
  list-style: none;
  gap: 2.5rem;
}

.nav-item {
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--color-text-muted);
  letter-spacing: 0.02em;
}

.nav-item:hover {
  color: var(--color-primary);
}

.nav-btn {
  padding: 0.6rem 1.4rem;
  font-size: 0.8rem;
}

/* ==========================================================================
   HERO SECTION
   ========================================================================== */

.hero-section {
  padding: 11rem 0 7rem 0;
  background-color: var(--color-bg-white);
  border-bottom: var(--border-main);
}

.hero-grid {
  display: grid;
  grid-template-columns: 1.25fr 0.75fr;
  gap: 4rem;
  align-items: center;
}

.hero-headline {
  font-size: clamp(2.5rem, 5vw, 3.85rem);
  color: var(--color-text-dark);
  margin-bottom: 1.5rem;
  font-weight: 700;
  line-height: 1.15;
}

.hero-subheadline {
  font-size: clamp(1.1rem, 2vw, 1.25rem);
  color: var(--color-text-muted);
  margin-bottom: 3rem;
  font-weight: 400;
  line-height: 1.6;
}

.hero-actions {
  display: flex;
  align-items: center;
}

.hero-portrait-container {
  position: relative;
  display: flex;
  justify-content: center;
}

.portrait-frame {
  width: 100%;
  max-width: 380px;
  background-color: var(--color-bg-white);
  padding: 8px;
  border-radius: var(--border-radius-md);
  border: var(--border-main);
  transition: var(--transition-smooth);
}

.portrait-frame:hover {
  border-color: var(--color-primary);
}

.portrait-img {
  width: 100%;
  aspect-ratio: 3/4;
  object-fit: cover;
  border-radius: var(--border-radius-sm);
  filter: grayscale(10%) contrast(1.02);
}

.portrait-caption {
  font-family: var(--font-sans);
  font-size: 0.8rem;
  font-weight: 600;
  color: var(--color-primary);
  text-align: center;
  margin-top: 0.75rem;
  line-height: 1.4;
  letter-spacing: -0.01em;
}

/* ==========================================================================
   INSTRUCTOR CREDIBILITY STRIP
   ========================================================================== */

.credibility-section {
  padding: 7rem 0;
  background-color: var(--color-bg-light);
  border-bottom: var(--border-main);
}

.credibility-grid {
  display: grid;
  grid-template-columns: 1.15fr 0.85fr;
  gap: 5rem;
  align-items: center;
}

.section-title {
  font-size: 2.25rem;
  color: var(--color-text-dark);
  margin-bottom: 1.25rem;
}

.section-lead {
  font-size: 1.1rem;
  color: var(--color-text-muted);
  margin-bottom: 3rem;
}

.metrics-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 2rem;
}

.metric-card {
  border-left: 2px solid var(--color-primary);
  padding-left: 1.5rem;
}

.metric-number {
  display: block;
  font-family: var(--font-serif);
  font-size: 2.25rem;
  font-weight: 700;
  color: var(--color-primary);
  line-height: 1.1;
}

.metric-label {
  display: block;
  font-size: 0.9rem;
  color: var(--color-text-dark);
  font-weight: 500;
  margin-top: 0.25rem;
}

.credibility-photo-container {
  display: flex;
  justify-content: center;
}

.photo-frame {
  position: relative;
  width: 100%;
  max-width: 440px;
  border-radius: var(--border-radius-md);
  border: var(--border-main);
  background-color: var(--color-bg-white);
  padding: 8px;
  overflow: hidden;
}

.teaching-img {
  width: 100%;
  aspect-ratio: 4/3;
  object-fit: cover;
}

.teaching-badge-logo {
  position: absolute;
  bottom: 1.5rem;
  left: 1.5rem;
  background-color: var(--color-bg-white);
  padding: 0.4rem 0.6rem;
  border: 1px solid #e5e5e5;
  display: flex;
  align-items: center;
  justify-content: center;
}

.logo-badge-img {
  height: 20px;
  width: auto;
  display: block;
}

/* ==========================================================================
   WHAT YOU'LL LEARN
   ========================================================================== */

.learn-section {
  padding: 8rem 0;
  background-color: var(--color-bg-white);
}

.section-header {
  max-width: 700px;
  margin: 0 auto 5rem auto;
}

.section-heading {
  font-size: 2.5rem;
  color: var(--color-text-dark);
  margin-bottom: 1rem;
}

.section-desc {
  font-size: 1.15rem;
  color: var(--color-text-muted);
}

.modules-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: 2rem;
}

.module-card {
  background-color: var(--color-bg-white);
  border: var(--border-main);
  border-radius: var(--border-radius-md);
  padding: 2.5rem;
  transition: var(--transition-smooth);
}

.module-card:hover {
  border-color: var(--color-primary);
}

.module-icon {
  width: 44px;
  height: 44px;
  color: var(--color-primary);
  margin-bottom: 1.5rem;
}

.module-number {
  font-size: 0.75rem;
  font-weight: 700;
  text-transform: uppercase;
  color: var(--color-primary);
  letter-spacing: 0.1em;
  margin-bottom: 0.5rem;
}

.module-title {
  font-size: 1.25rem;
  color: var(--color-text-dark);
  margin-bottom: 1rem;
}

.module-desc {
  font-size: 0.9rem;
  color: var(--color-text-muted);
  line-height: 1.6;
}

/* ==========================================================================
   WHAT YOU GET SECTION (HBS Light Style)
   ========================================================================== */

.deliverables-section {
  padding: 8rem 0;
  background-color: var(--color-bg-light);
  color: var(--color-text-dark);
  border-top: var(--border-main);
  border-bottom: var(--border-main);
}

.deliverables-container {
  max-width: 900px;
  margin: 0 auto;
}

.deliverables-header {
  text-align: center;
  margin-bottom: 4rem;
}

.section-heading-light {
  font-family: var(--font-serif);
  font-size: 2.5rem;
  color: var(--color-text-dark);
  margin-bottom: 1rem;
}

.section-desc-light {
  font-size: 1.15rem;
  color: var(--color-text-muted);
}

.deliverables-list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 1.25rem;
}

.deliverable-item {
  display: flex;
  align-items: flex-start;
  padding: 1.5rem 2rem;
  background-color: var(--color-bg-white);
  border: var(--border-main);
  border-radius: var(--border-radius-md);
  transition: var(--transition-smooth);
}

.deliverable-item:hover {
  border-color: var(--color-primary);
}

.check-icon {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 24px;
  height: 24px;
  background-color: rgba(225, 6, 0, 0.1);
  color: var(--color-primary);
  border-radius: 50%;
  margin-right: 1.25rem;
  flex-shrink: 0;
  margin-top: 0.25rem;
}

.deliverable-text {
  font-size: 1.05rem;
  color: var(--color-text-dark);
}

.deliverable-text strong {
  color: var(--color-primary);
  font-weight: 700;
}

/* ==========================================================================
   WHY THIS COURSE (Persuasive block)
   ========================================================================== */

.why-section {
  padding: 8rem 0;
  background-color: var(--color-bg-white);
  border-bottom: var(--border-main);
}

.why-grid {
  display: grid;
  grid-template-columns: 1.1fr 0.9fr;
  gap: 5rem;
  align-items: center;
}

.why-body p {
  font-size: 1.05rem;
  color: var(--color-text-muted);
  margin-bottom: 1.5rem;
  line-height: 1.7;
}

.why-body blockquote {
  font-family: var(--font-serif);
  font-size: 1.35rem;
  font-weight: 600;
  color: var(--color-text-dark);
  border-left: 2px solid var(--color-primary);
  padding-left: 1.5rem;
  margin: 2rem 0;
  font-style: italic;
  line-height: 1.5;
}

/* Flat McKinsey Chart Card */
.chart-card {
  background-color: var(--color-bg-light);
  border-radius: var(--border-radius-md);
  padding: 2.5rem;
  border: var(--border-main);
}

.chart-header h3 {
  font-size: 1.15rem;
  color: var(--color-text-dark);
  margin-bottom: 0.25rem;
}

.chart-header p {
  font-size: 0.85rem;
  color: var(--color-text-muted);
  margin-bottom: 2rem;
}

.chart-content {
  display: flex;
  flex-direction: column;
  gap: 1.5rem;
}

.bar-group {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

.bar-label {
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--color-text-dark);
}

.bar-outer {
  background-color: rgba(0, 0, 0, 0.05);
  border-radius: var(--border-radius-sm);
  height: 28px;
  overflow: hidden;
}

.bar-inner {
  background-color: var(--color-text-muted-dark);
  height: 100%;
  display: flex;
  align-items: center;
  padding-left: 1rem;
  font-size: 0.8rem;
  font-weight: 700;
  color: var(--color-text-light);
  border-radius: var(--border-radius-sm);
}

.bar-group.highlight .bar-inner {
  background-color: var(--color-primary);
}

.chart-footer {
  font-size: 0.75rem;
  color: var(--color-text-muted);
  margin-top: 2rem;
  border-top: var(--border-main);
  padding-top: 1rem;
}

/* ==========================================================================
   LOGISTICS SECTION
   ========================================================================== */

.logistics-section {
  padding: 5rem 0;
  background-color: var(--color-bg-light);
  border-bottom: var(--border-main);
}

.logistics-wrapper {
  background-color: var(--color-bg-white);
  border-radius: var(--border-radius-lg);
  padding: 3.5rem;
  border: var(--border-main);
}

.logistics-grid {
  display: grid;
  grid-template-columns: 1.25fr 1fr;
  gap: 3.5rem;
  align-items: center;
}

@media (max-width: 992px) {
  .logistics-grid {
    grid-template-columns: 1fr;
    gap: 3rem;
  }
}

.logistics-visual {
  width: 100%;
}

.venue-image-container {
  border: 1px solid #e5e5e5;
  background-color: var(--color-bg-white);
  padding: 10px;
}

.venue-img {
  width: 100%;
  aspect-ratio: 4 / 3;
  object-fit: cover;
  display: block;
}

.venue-caption {
  font-family: var(--font-serif);
  font-size: 0.85rem;
  font-style: italic;
  color: var(--color-text-muted);
  margin-top: 0.75rem;
  text-align: center;
}

.maps-link {
  display: inline-block;
  margin-top: 0.75rem;
  font-weight: 600;
  color: var(--color-primary);
  font-size: 0.9rem;
  text-decoration: underline;
  text-underline-offset: 4px;
  transition: var(--transition-fast);
}

.maps-link:hover {
  color: var(--color-primary-hover);
  text-decoration-color: transparent;
}

.logistics-badge {
  display: inline-block;
  font-size: 0.8rem;
  font-weight: 700;
  color: var(--color-primary);
  text-transform: uppercase;
  letter-spacing: 0.15em;
  margin-bottom: 0.75rem;
}

.logistics-heading {
  font-size: 2rem;
  color: var(--color-text-dark);
  margin-bottom: 2.5rem;
}

.details-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 2.5rem;
}

.detail-item {
  display: flex;
  align-items: flex-start;
}

.detail-icon {
  font-size: 1.75rem;
  margin-right: 1.25rem;
  line-height: 1;
  color: var(--color-primary);
}

.detail-content h4 {
  font-family: var(--font-serif);
  font-size: 1.05rem;
  color: var(--color-text-dark);
  margin-bottom: 0.5rem;
}

.detail-content p {
  font-size: 0.95rem;
  color: var(--color-text-muted);
}

.detail-content p.highlight-text {
  color: var(--color-primary);
  font-weight: 700;
  font-size: 1.15rem;
}

/* ==========================================================================
   BOOKING FORM SECTION
   ========================================================================== */

.booking-section {
  padding: 8rem 0;
  background-color: var(--color-bg-white);
}

.booking-card {
  background-color: var(--color-bg-white);
  border: var(--border-main);
  border-radius: var(--border-radius-lg);
  padding: 3.5rem;
  position: relative;
  overflow: hidden;
}

.booking-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 4px;
  background-color: var(--color-primary);
}

.booking-title {
  font-size: 2.25rem;
  color: var(--color-text-dark);
  margin-bottom: 0.5rem;
}

.booking-subtitle {
  font-size: 1.05rem;
  color: var(--color-text-muted);
  margin-bottom: 3.5rem;
}

.form-group {
  margin-bottom: 1.75rem;
  position: relative;
}

.form-group label {
  display: block;
  font-size: 0.85rem;
  font-weight: 700;
  color: var(--color-text-dark);
  margin-bottom: 0.5rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.required {
  color: var(--color-primary);
}

.form-control {
  width: 100%;
  padding: 0.9rem 1.25rem;
  font-family: var(--font-sans);
  font-size: 0.95rem;
  color: var(--color-text-dark);
  background-color: var(--color-bg-white);
  border: var(--border-main);
  border-radius: var(--border-radius-sm);
  outline: none;
  transition: var(--transition-fast);
}

.form-control:focus {
  border-color: var(--color-primary);
}

.form-control::placeholder {
  color: var(--color-text-muted-dark);
}

.select-wrapper {
  position: relative;
}

.select-wrapper::after {
  content: '▼';
  font-size: 0.7rem;
  color: var(--color-text-muted);
  position: absolute;
  right: 1.25rem;
  top: 50%;
  transform: translateY(-50%);
  pointer-events: none;
}

.select-control {
  appearance: none;
  -webkit-appearance: none;
  padding-right: 3rem;
}

.textarea-control {
  resize: vertical;
}

/* Input validation styles */
.form-group.has-error .form-control {
  border-color: var(--color-primary);
  background-color: rgba(225, 6, 0, 0.01);
}

.error-msg {
  color: var(--color-primary);
  font-size: 0.8rem;
  font-weight: 600;
  margin-top: 0.35rem;
  display: none;
}

.form-group.has-error .error-msg {
  display: block;
}

/* LINE button styling */
.btn-line {
  background-color: #06c755; /* LINE Green */
  color: #ffffff;
  border: none;
}

.btn-line:hover {
  background-color: #05b04b;
  color: #ffffff;
}

/* Success State Style */
.booking-success-state {
  text-align: center;
  padding: 2rem 0;
  animation: fadeIn 0.3s ease-out;
}

.success-icon {
  width: 60px;
  height: 60px;
  background-color: rgba(52, 199, 89, 0.1);
  color: var(--color-success);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 2rem;
  font-weight: bold;
  margin: 0 auto 1.5rem auto;
  border: 1px solid var(--color-success);
}

.booking-success-state h3 {
  font-size: 1.5rem;
  color: var(--color-text-dark);
  margin-bottom: 0.75rem;
}

.success-desc {
  font-size: 1rem;
  color: var(--color-text-muted);
  margin-bottom: 2rem;
}

.success-fallback-box {
  background-color: var(--color-bg-light);
  padding: 1.5rem;
  border-radius: var(--border-radius-md);
  margin-bottom: 2rem;
  border: var(--border-main);
}

.success-fallback-box p {
  font-size: 0.9rem;
  color: var(--color-text-dark);
  margin-bottom: 1rem;
}

.success-footer {
  font-size: 0.85rem;
  color: var(--color-text-muted);
  font-weight: 600;
}

/* ==========================================================================
   FOOTER
   ========================================================================== */

.site-footer {
  background-color: var(--color-bg-dark);
  color: var(--color-text-light);
  padding: 5rem 0 2rem 0;
  border-top: 1px solid rgba(255, 255, 255, 0.05);
}

.footer-container {
  display: grid;
  grid-template-columns: 1.2fr 0.8fr;
  gap: 4rem;
  margin-bottom: 4rem;
}

.footer-brand {
  max-width: 450px;
}

.footer-brand p {
  font-size: 0.9rem;
  color: var(--color-text-muted-dark);
  margin-top: 1rem;
}

.footer-contacts h4 {
  font-size: 0.85rem;
  font-weight: 700;
  color: var(--color-text-light);
  margin-bottom: 1.25rem;
  text-transform: uppercase;
  letter-spacing: 0.15em;
}

.footer-contacts ul {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}

.footer-link {
  font-size: 0.95rem;
  color: var(--color-text-muted-dark);
  border-bottom: 1px solid transparent;
}

.footer-link:hover {
  color: var(--color-accent);
  border-bottom-color: var(--color-accent);
}

.footer-bottom {
  border-top: 1px solid rgba(255, 255, 255, 0.06);
  padding-top: 2rem;
  font-size: 0.8rem;
  color: var(--color-text-muted-dark);
}

/* ==========================================================================
   SCROLL EFFECTS & FADE IN
   ========================================================================== */

.fade-in-reveal {
  opacity: 0;
  transform: translateY(20px);
  transition: opacity 0.6s ease-out, transform 0.6s ease-out;
}

.fade-in-reveal.active {
  opacity: 1;
  transform: translateY(0);
}

@keyframes fadeIn {
  from {
    opacity: 0;
    transform: translateY(10px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

/* ==========================================================================
   DETAILED COURSE SYLLABUS TIMELINE
   ========================================================================== */

.detailed-syllabus {
  margin-top: 6rem;
  border-top: var(--border-main);
  padding-top: 6rem;
}

.timeline-title {
  font-size: 2.25rem;
  color: var(--color-text-dark);
  margin-bottom: 4rem;
}

.syllabus-timeline-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 3rem;
  align-items: start;
}

.day-card {
  background-color: var(--color-bg-white);
  border: var(--border-main);
  border-radius: var(--border-radius-lg);
  padding: 3rem;
  transition: var(--transition-smooth);
}

.day-card:hover {
  border-color: var(--color-primary);
}

.day-badge-header {
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
  margin-bottom: 3rem;
  border-bottom: var(--border-main);
  padding-bottom: 1.5rem;
}

.day-number-badge {
  display: inline-block;
  font-size: 0.7rem;
  font-weight: 700;
  background-color: var(--color-primary);
  color: var(--color-text-light);
  padding: 0.25rem 0.65rem;
  border-radius: var(--border-radius-sm);
  align-self: flex-start;
  letter-spacing: 0.1em;
}

.day-theme {
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--color-text-dark);
  line-height: 1.3;
}

.timeline-items {
  display: flex;
  flex-direction: column;
  gap: 2.5rem;
}

.timeline-item-detail {
  display: flex;
  gap: 1.5rem;
  align-items: flex-start;
}

.time-box {
  width: 120px;
  font-size: 0.75rem;
  font-weight: 700;
  background-color: var(--color-bg-light);
  color: var(--color-text-muted);
  text-align: center;
  padding: 0.4rem 0.5rem;
  border-radius: var(--border-radius-sm);
  flex-shrink: 0;
  border: var(--border-main);
}

.timeline-item-detail.highlight-lab .time-box {
  background-color: rgba(225, 6, 0, 0.05);
  color: var(--color-primary);
  border-color: rgba(225, 6, 0, 0.25);
}

.content-box h4 {
  font-family: var(--font-serif);
  font-size: 1.05rem;
  font-weight: 700;
  color: var(--color-text-dark);
  margin-bottom: 0.5rem;
  line-height: 1.4;
}

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

.content-box code {
  font-family: Consolas, Monaco, "Andale Mono", monospace;
  font-size: 0.85rem;
  background-color: var(--color-bg-light);
  padding: 0.1rem 0.3rem;
  border-radius: 3px;
  color: var(--color-primary);
}

/* ==========================================================================
   RESPONSIVE LAYOUTS (Mobile-First approach)
   ========================================================================== */

@media (max-w: 992px) {
  .hero-grid, .credibility-grid, .why-grid {
    grid-template-columns: 1fr;
    gap: 3rem;
  }
  
  .hero-content {
    text-align: center;
  }
  
  .hero-actions {
    justify-content: center;
  }
  
  .hero-portrait-container {
    order: -1; /* Place image above text on smaller screens */
  }
  
  .credibility-photo-container {
    order: -1;
  }
  
  .why-chart {
    order: 1;
  }
  
  .footer-container {
    grid-template-columns: 1fr;
    gap: 3rem;
  }

  .syllabus-timeline-grid {
    grid-template-columns: 1fr;
    gap: 2.5rem;
  }
}

@media (max-w: 768px) {
  html {
    font-size: 15px;
  }
  
  .container {
    padding: 0 1.5rem;
  }
  
  .header-container {
    padding: 1rem 1.5rem;
  }
  
  .desktop-nav {
    display: none; /* Hide desktop nav links on mobile/tablet */
  }
  
  .hero-section {
    padding: 9rem 0 4rem 0;
  }
  
  .hero-actions {
    flex-direction: column;
    width: 100%;
    gap: 1rem;
  }
  
  .btn-tertiary {
    margin-left: 0;
  }
  
  .btn-block {
    width: 100%;
  }
  
  .why-section, .learn-section, .deliverables-section, .booking-section {
    padding: 5rem 0;
  }
  
  .logistics-wrapper {
    padding: 2.5rem 1.5rem;
  }
  
  .details-grid {
    gap: 1.5rem;
  }
  
  .booking-card {
    padding: 2.5rem 1.5rem;
  }
}

@media (max-w: 576px) {
  .day-card {
    padding: 2rem 1.5rem;
  }
  
  .timeline-item-detail {
    flex-direction: column;
    gap: 0.75rem;
  }
  
  .time-box {
    align-self: flex-start;
  }
}

@media (max-w: 480px) {
  html {
    font-size: 14px;
  }
  
  .portrait-frame {
    max-width: 100%;
  }
  
  .nav-cta {
    display: none; /* Hide navbar CTA to save space on small screens */
  }
}

.instructor-name-top {
  font-family: var(--font-serif);
  font-size: 1.45rem;
  font-weight: 700;
  color: var(--color-text-dark);
  text-align: center;
  margin-bottom: 0.75rem;
}

.btn-download {
  display: inline-block;
  padding: 0.65rem 1.5rem;
  border: 1px solid var(--color-primary);
  background-color: var(--color-bg-white);
  color: var(--color-primary);
  font-family: var(--font-sans);
  font-size: 0.9rem;
  font-weight: 600;
  text-decoration: none;
  transition: var(--transition-smooth);
}

.btn-download:hover {
  background-color: var(--color-primary);
  color: var(--color-bg-white);
}