:root {
  --primary: #d5ff00;
  --primary-hover: #c4eb00;
  --bg-color: #fafafa;
  --bg-white: #ffffff;
  --text-main: #111827;
  --text-muted: #6b7280;
  --text-light: #9ca3af;
  --border-color: #e5e7eb;
  --dark-bg: #1f2937;
  --dark-card: #2d3748;

  --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.05), 0 2px 4px -1px rgba(0, 0, 0, 0.03);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.05), 0 4px 6px -2px rgba(0, 0, 0, 0.025);

  --radius-sm: 6px;
  --radius-md: 12px;
  --radius-lg: 24px;
}

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

body {
  font-family: 'Inter', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  background-color: var(--bg-color);
  color: var(--text-main);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

a {
  text-decoration: none;
  color: inherit;
  transition: color 0.2s;
}

ul { list-style: none; }
img { max-width: 100%; height: auto; }

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

/* ─── Typography ───────────────────────────── */
h1, h2, h3, h4 {
  color: var(--text-main);
  letter-spacing: -0.02em;
  line-height: 1.15;
}

.highlight {
  background-color: var(--primary);
  color: var(--text-main);
  padding: 0 0.2em;
  border-radius: var(--radius-sm);
}

.section-label {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  font-size: 0.75rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--text-muted);
  margin-bottom: 1.5rem;
}

.section-label .dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background-color: var(--primary);
}

.section-title {
  font-size: 2.5rem;
  font-weight: 800;
}

.section-subtitle {
  color: var(--text-muted);
  font-size: 1rem;
  margin-top: 1rem;
  max-width: 640px;
  margin-left: auto;
  margin-right: auto;
}

/* ─── Buttons ──────────────────────────────── */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  padding: 0.625rem 1.25rem;
  border-radius: 9999px;
  font-weight: 500;
  font-size: 0.875rem;
  cursor: pointer;
  transition: all 0.2s ease;
  border: none;
}

.btn-lg {
  padding: 0.875rem 1.75rem;
  font-size: 1rem;
}

.btn-primary {
  background-color: var(--primary);
  color: var(--text-main);
}
.btn-primary:hover {
  background-color: var(--primary-hover);
  transform: translateY(-1px);
}

.btn-secondary {
  background-color: var(--bg-white);
  color: var(--text-main);
  border: 1px solid var(--border-color);
}
.btn-secondary:hover {
  border-color: var(--text-muted);
  background-color: #f9f9f9;
}

.btn-dark {
  background-color: #2b303a;
  color: white;
}
.btn-dark:hover {
  background-color: #1a1e24;
}

/* ─── Navbar ───────────────────────────────── */
.navbar {
  position: fixed;
  top: 0;
  width: 100%;
  background-color: rgba(255, 255, 255, 0.8);
  backdrop-filter: blur(12px);
  z-index: 100;
  border-bottom: 1px solid rgba(0,0,0,0.05);
}

.nav-container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 4.5rem;
}

.logo {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-weight: 700;
  font-size: 1.25rem;
}

.logo-icon {
  color: var(--primary);
  font-size: 1.5rem;
  display: flex;
}

.nav-links {
  display: flex;
  gap: 2rem;
}

.nav-links a {
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--text-muted);
}
.nav-links a:hover {
  color: var(--text-main);
}

.nav-actions {
  display: flex;
  align-items: center;
  gap: 1.5rem;
}

/* ─── Hero ─────────────────────────────────── */
.hero {
  padding: 10rem 0 6rem;
  text-align: center;
  background: radial-gradient(circle at top, #ffffff, #fafafa);
}

.hero .badge {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  background: #f3f4f6;
  padding: 0.25rem 0.75rem;
  border-radius: 999px;
  font-size: 0.75rem;
  font-weight: 600;
  color: var(--text-muted);
  margin-bottom: 2rem;
  border: 1px solid var(--border-color);
}

.hero .badge i {
  color: #10b981;
}

.hero-title {
  font-size: 4rem;
  font-weight: 800;
  margin-bottom: 1.5rem;
}

.hero-subtitle {
  font-size: 1.125rem;
  color: var(--text-muted);
  margin-bottom: 2.5rem;
  max-width: 640px;
  margin-left: auto;
  margin-right: auto;
}

.hero-cta {
  display: flex;
  justify-content: center;
  gap: 1rem;
}

/* ─── About the Study ──────────────────────── */
.about-study {
  padding: 0 0 6rem;
}

.about-card {
  background: var(--bg-white);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-lg), 0 20px 40px -10px rgba(0,0,0,0.05);
  border: 1px solid var(--border-color);
  overflow: hidden;
  max-width: 1000px;
  margin: 0 auto;
  padding: 3rem;
}

.about-header {
  margin-bottom: 2.5rem;
  text-align: center;
}

.research-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 2rem;
  margin-bottom: 4rem;
}

.research-card {
  background: var(--bg-white);
  padding: 2.5rem;
  border-radius: var(--radius-md);
  border: 1px solid var(--border-color);
  box-shadow: var(--shadow-sm);
  transition: transform 0.3s;
}

.research-card:hover {
  transform: translateY(-4px);
}

.research-card.highlight-card {
  background: #fdfcf4;
  border-color: #ebe7d0;
}

.card-icon {
  font-size: 2rem;
  color: var(--primary);
  margin-bottom: 1rem;
  background: #202124;
  width: 48px;
  height: 48px;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: var(--radius-sm);
  border: 1px solid rgba(0,0,0,0.1);
}

.research-card h3 {
  font-size: 1.25rem;
  margin-bottom: 1rem;
}

.research-card p {
  color: var(--text-muted);
  font-size: 0.9375rem;
  line-height: 1.7;
}

.constraints-section {
  background: #202124;
  color: white;
  padding: 3rem;
  border-radius: var(--radius-md);
  margin-bottom: 4rem;
  position: relative;
  overflow: hidden;
}

.constraints-section::before {
  content: "";
  position: absolute;
  top: -100px;
  right: -100px;
  width: 300px;
  height: 300px;
  background: radial-gradient(circle, rgba(213,255,0,0.15) 0%, rgba(0,0,0,0) 70%);
  border-radius: 50%;
  z-index: 0;
}

.constraints-section > * {
  position: relative;
  z-index: 1;
}

.constraints-section h3 {
  color: white;
  margin-bottom: 1rem;
  font-size: 1.5rem;
  display: flex;
  align-items: center;
  gap: 0.5rem;
}
.constraints-section h3 i {
  color: var(--primary);
}

.constraints-section > p {
  color: #9ca3af;
  margin-bottom: 2rem;
  max-width: 700px;
  font-size: 0.9375rem;
}

.constraints-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1.5rem;
}

.constraint-item {
  background: rgba(255, 255, 255, 0.03);
  padding: 1.5rem;
  border-radius: var(--radius-sm);
  border: 1px solid rgba(255, 255, 255, 0.1);
}

.constraint-item strong {
  display: block;
  font-size: 1.125rem;
  margin-bottom: 0.5rem;
  color: var(--primary);
}

.constraint-item span {
  font-size: 0.875rem;
  color: #d1d5db;
  line-height: 1.6;
}

.about-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 3rem;
  align-items: stretch;
  background: white;
  padding: 3rem;
  border-radius: var(--radius-md);
  border: 1px solid var(--border-color);
  box-shadow: var(--shadow-sm);
}

.about-text p {
  color: var(--text-muted);
  font-size: 0.9375rem;
  margin-bottom: 1rem;
  line-height: 1.7;
}

.about-text strong {
  color: var(--text-main);
}

.about-methodology h3 {
  font-size: 1.25rem;
  font-weight: 700;
  margin-bottom: 1.5rem;
}

.method-steps {
  display: flex;
  flex-direction: column;
  gap: 1.25rem;
}

.method-step {
  display: flex;
  gap: 1rem;
  align-items: flex-start;
}

.step-number {
  font-size: 1.5rem;
  font-weight: 800;
  color: var(--primary);
  min-width: 40px;
  line-height: 1;
  padding-top: 0.1rem;
  text-shadow: 0 0 20px rgba(213, 255, 0, 0.3);
}

.step-content {
  display: flex;
  flex-direction: column;
  gap: 0.25rem;
}

.step-content strong {
  font-size: 0.9375rem;
  font-weight: 600;
}

.step-content span {
  font-size: 0.8125rem;
  color: var(--text-muted);
  line-height: 1.5;
}

/* ─── Key Stats ────────────────────────────── */
.key-stats {
  padding: 6rem 0;
  text-align: center;
  background: white;
}

.stats-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 2rem;
  margin-top: 3rem;
}

.stat-number {
  font-size: 3.5rem;
  font-weight: 800;
  line-height: 1;
  margin-bottom: 1rem;
}

.stat-number span {
  font-size: 1.75rem;
  color: var(--text-main);
}

.stat-desc {
  color: var(--text-muted);
  font-size: 0.875rem;
  line-height: 1.6;
}

/* ─── Results ──────────────────────────────── */
.results {
  padding: 6rem 0;
  text-align: center;
  background: #fafafa;
}

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

.results-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 2rem;
}

.result-card {
  background: var(--bg-white);
  border-radius: var(--radius-md);
  border: 1px solid var(--border-color);
  box-shadow: var(--shadow-sm);
  overflow: hidden;
  transition: transform 0.3s ease, box-shadow 0.3s ease;
  text-align: left;
}

.result-card:hover {
  transform: translateY(-5px);
  box-shadow: var(--shadow-md);
}

.result-card.full-width {
  grid-column: 1 / -1;
}

.result-img-wrapper {
  background: #f8f9fa;
  padding: 1.5rem;
  border-bottom: 1px solid var(--border-color);
  display: flex;
  align-items: center;
  justify-content: center;
}

.result-img-wrapper img {
  max-height: 320px;
  object-fit: contain;
  border-radius: var(--radius-sm);
}

.result-info {
  padding: 1.5rem 2rem;
}

.result-title {
  font-size: 1.125rem;
  font-weight: 700;
  margin-bottom: 0.75rem;
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.result-title i {
  color: var(--primary);
  background: #f3f4f6;
  width: 32px;
  height: 32px;
  border-radius: var(--radius-sm);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1rem;
  border: 1px solid var(--border-color);
  flex-shrink: 0;
}

.result-desc {
  color: var(--text-muted);
  font-size: 0.875rem;
  line-height: 1.6;
}

.result-desc strong {
  color: var(--text-main);
}

/* ─── ML Model ─────────────────────────────── */
.ml-model {
  padding: 6rem 0;
  background: white;
}

.model-showcase {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 4rem;
  align-items: center;
  max-width: 1000px;
  margin: 0 auto;
}

.model-desc {
  color: var(--text-muted);
  font-size: 0.9375rem;
  line-height: 1.7;
  margin-bottom: 2rem;
}

.model-features {
  display: flex;
  flex-direction: column;
  gap: 1rem;
  margin-bottom: 2.5rem;
}

.model-feature {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  font-size: 0.875rem;
  font-weight: 500;
}

.model-feature i {
  color: var(--primary);
  font-size: 1.25rem;
  width: 36px;
  height: 36px;
  background: #f3f4f6;
  border-radius: var(--radius-sm);
  display: flex;
  align-items: center;
  justify-content: center;
  border: 1px solid var(--border-color);
}

.model-note {
  margin-top: 1rem;
  font-size: 0.75rem;
  color: var(--text-light);
  font-style: italic;
}

/* Code Block Visual */
.code-block {
  background: #1a1d23;
  border-radius: var(--radius-md);
  overflow: hidden;
  box-shadow: var(--shadow-lg);
  border: 1px solid #2d3748;
}

.code-header {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 0.875rem 1rem;
  border-bottom: 1px solid #2d3748;
  background: rgba(255,255,255,0.03);
}

.code-dot {
  width: 12px;
  height: 12px;
  border-radius: 50%;
}
.code-dot.red { background: #ff5f56; }
.code-dot.yellow { background: #ffbd2e; }
.code-dot.green { background: #27c93f; }

.code-filename {
  margin-left: auto;
  color: #6b7280;
  font-size: 0.75rem;
  font-weight: 500;
}

.code-block pre {
  padding: 1.5rem;
  font-family: 'JetBrains Mono', 'Fira Code', 'Courier New', monospace;
  font-size: 0.8125rem;
  line-height: 1.7;
  color: #e5e7eb;
  overflow-x: auto;
}

.code-block .kw { color: #c084fc; }
.code-block .str { color: #a3be8c; }
.code-block .comment { color: #6b7280; font-style: italic; }

/* ─── Future Scope (Accordion) ─────────────── */
.future-scope {
  padding: 6rem 0;
  background: #fafafa;
}

.future-container {
  max-width: 800px;
}

.scope-accordion {
  margin-top: 0;
}

.scope-item {
  background: white;
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
  margin-bottom: 1rem;
  overflow: hidden;
}

.scope-question {
  width: 100%;
  text-align: left;
  padding: 1.5rem;
  background: none;
  border: none;
  font-size: 1.0625rem;
  font-weight: 600;
  color: var(--text-main);
  cursor: pointer;
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-family: inherit;
  transition: color 0.2s;
}

.scope-question:hover {
  color: #000;
}

.scope-question i {
  transition: transform 0.3s;
  flex-shrink: 0;
  margin-left: 1rem;
}

.scope-answer {
  padding: 0 1.5rem;
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.3s ease, padding 0.3s ease;
  color: var(--text-muted);
  font-size: 0.875rem;
  line-height: 1.6;
}

.scope-item.active .scope-answer {
  padding: 0 1.5rem 1.5rem;
  max-height: 200px;
}

.scope-item.active .scope-question i {
  transform: rotate(45deg);
}

/* ─── Footer CTA ───────────────────────────── */
.footer {
  padding: 6rem 0 2rem;
  background: white;
}

.cta-card {
  background: #202124;
  border-radius: var(--radius-lg);
  padding: 5rem 2rem;
  text-align: center;
  color: white;
  position: relative;
  overflow: hidden;
  margin-bottom: 4rem;
}

.glow-effect {
  position: absolute;
  bottom: -100px;
  left: -100px;
  width: 300px;
  height: 300px;
  background: radial-gradient(circle, rgba(213,255,0,0.2) 0%, rgba(0,0,0,0) 70%);
  border-radius: 50%;
}

.cta-title {
  color: white;
  font-size: 2.75rem;
  font-weight: 800;
  margin-bottom: 1rem;
  position: relative;
  z-index: 1;
}

.cta-desc {
  color: #9ca3af;
  margin-bottom: 2.5rem;
  position: relative;
  z-index: 1;
}

.cta-actions {
  display: flex;
  justify-content: center;
  gap: 1rem;
  position: relative;
  z-index: 1;
}

.text-light { color: #9ca3af; }

.footer-bottom {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding-top: 2rem;
  border-top: 1px solid var(--border-color);
  font-size: 0.875rem;
  color: var(--text-muted);
}

.footer-logo {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-weight: 700;
  color: var(--text-main);
  font-size: 1.25rem;
}
.footer-logo i { color: var(--text-main); }

.footer-links {
  display: flex;
  gap: 1.5rem;
}

/* ─── Animations ───────────────────────────── */
@keyframes fadeUp {
  from { opacity: 0; transform: translateY(20px); }
  to { opacity: 1; transform: translateY(0); }
}

.fade-up {
  opacity: 0;
  animation: fadeUp 0.8s ease forwards;
}