/* Scientific Editor — Thoughtlane theme */
:root {
  --primary: #0d6b8a;
  --primary-light: #1493b8;
  --accent: #0ea88c;
  --accent-light: #2dd4bf;
  --bg: #0c1222;
  --bg-card: #151d2e;
  --bg-muted: #1e293b;
  --text: #e2e8f0;
  --text-muted: #94a3b8;
  --border: rgba(255, 255, 255, 0.08);
  --font-sans: 'DM Sans', system-ui, sans-serif;
  --font-serif: 'Fraunces', serif;
  --font-mono: 'JetBrains Mono', monospace;
  --radius: 10px;
  --space: 1.5rem;
  --container: min(90vw, 1100px);
}

body:not(.dark-theme) {
  --bg: #f8fafc;
  --bg-card: #ffffff;
  --bg-muted: #f1f5f9;
  --text: #0f172a;
  --text-muted: #64748b;
  --border: rgba(15, 23, 42, 0.1);
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: var(--font-sans);
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  transition: background 0.4s ease, color 0.4s ease;
}

h1, h2, h3 {
  font-family: var(--font-serif);
}

.container {
  width: 100%;
  max-width: var(--container);
  margin: 0 auto;
  padding: 0 var(--space);
}

/* Header */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(12, 18, 34, 0.72);
  backdrop-filter: blur(20px) saturate(180%);
  -webkit-backdrop-filter: blur(20px) saturate(180%);
  border-bottom: 1px solid var(--border);
  transition: background 0.4s ease;
}

body:not(.dark-theme) .site-header {
  background: rgba(248, 250, 252, 0.72);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 1rem var(--space);
}

.header-left {
  display: flex;
  align-items: center;
  gap: var(--space);
}

.logo-back {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  color: var(--text-muted);
  text-decoration: none;
  font-size: 0.9rem;
  font-weight: 500;
  transition: color 0.2s ease;
}

.logo-back:hover {
  color: var(--accent-light);
}

.logo-img {
  height: 56px;
  width: auto;
}

.logo {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  text-decoration: none;
  color: var(--text);
  font-weight: 700;
  font-size: 1.15rem;
}

.logo-icon {
  width: 2rem;
  height: 2rem;
  display: flex;
  align-items: center;
  justify-content: center;
  background: linear-gradient(135deg, var(--primary) 0%, var(--accent) 100%);
  color: white;
  border-radius: 6px;
  font-size: 1.2rem;
}

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

.nav a {
  color: var(--text-muted);
  text-decoration: none;
  font-weight: 500;
  transition: color 0.2s;
}

.nav a:hover {
  color: var(--accent-light);
}

.theme-toggle {
  width: 40px;
  height: 40px;
  border-radius: 10px;
  border: 1px solid var(--border);
  background: rgba(14, 168, 140, 0.15);
  color: var(--accent-light);
  cursor: pointer;
  font-size: 1.1rem;
  transition: all 0.2s ease;
}

.theme-toggle:hover {
  background: rgba(14, 168, 140, 0.25);
}

/* Buttons */
.btn {
  display: inline-block;
  padding: 0.6rem 1.2rem;
  border-radius: var(--radius);
  font-weight: 600;
  font-size: 0.95rem;
  text-decoration: none;
  transition: background 0.2s, color 0.2s;
  border: none;
  cursor: pointer;
}

.btn-primary {
  background: linear-gradient(135deg, var(--primary) 0%, var(--primary-light) 100%);
  color: white;
}

.btn-primary:hover {
  background: linear-gradient(135deg, var(--primary-light) 0%, var(--accent) 100%);
  color: white;
}

.btn-secondary {
  background: transparent;
  color: var(--accent-light);
  border: 2px solid var(--accent-light);
}

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

.btn-lg {
  padding: 0.85rem 1.6rem;
  font-size: 1rem;
}

/* Hero */
.hero {
  padding: 4rem 0 5rem;
  text-align: center;
}

.hero-title {
  margin: 0 0 1rem;
  font-size: clamp(2rem, 5vw, 3rem);
  font-weight: 700;
  line-height: 1.2;
  letter-spacing: -0.02em;
}

.hero-subtitle {
  margin: 0 auto 2rem;
  max-width: 560px;
  font-size: 1.2rem;
  color: var(--text-muted);
}

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

.hero-cta .btn-secondary {
  color: var(--text-muted);
  border-color: var(--bg-muted);
}

.hero-cta .btn-secondary:hover {
  background: var(--bg-muted);
  color: var(--text);
  border-color: var(--bg-muted);
}

/* Sections */
.section {
  padding: 3.5rem 0;
  border-top: 1px solid var(--border);
}

.section-title {
  margin: 0 0 0.5rem;
  font-size: 1.75rem;
  font-weight: 700;
  letter-spacing: -0.02em;
}

.section-lead {
  margin: 0 0 2rem;
  max-width: 640px;
  color: var(--text-muted);
  font-size: 1.05rem;
}

.section-lead a {
  color: var(--accent-light);
  text-decoration: none;
}

.section-lead a:hover {
  text-decoration: underline;
}

/* Problem / Solution */
.problem-solution .two-col {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1.5rem;
  margin-top: 1.5rem;
}

@media (max-width: 700px) {
  .problem-solution .two-col {
    grid-template-columns: 1fr;
  }
}

.card {
  padding: 1.5rem;
  border-radius: var(--radius);
  border: 1px solid var(--border);
}

.card-muted {
  background: var(--bg-card);
}

.card-highlight {
  background: rgba(14, 168, 140, 0.12);
  border-color: rgba(14, 168, 140, 0.3);
}

.card h3 {
  margin: 0 0 0.75rem;
  font-size: 1.1rem;
  font-weight: 600;
}

.card ul {
  margin: 0;
  padding-left: 1.25rem;
  color: var(--text-muted);
  font-size: 0.95rem;
}

.card li {
  margin-bottom: 0.35rem;
}

/* Features grid */
.feature-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
  gap: 1.5rem;
}

.feature-card {
  padding: 1.5rem;
  background: rgba(21, 29, 46, 0.5);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  transition: transform 0.35s cubic-bezier(0.4, 0, 0.2, 1), box-shadow 0.35s ease, border-color 0.2s;
}

body:not(.dark-theme) .feature-card {
  background: rgba(255, 255, 255, 0.7);
}

.feature-card:hover {
  border-color: var(--accent-light);
  transform: translateY(-2px);
  box-shadow: 0 12px 24px rgba(13, 107, 138, 0.15);
}

.feature-icon {
  width: 2.5rem;
  height: 2.5rem;
  display: flex;
  align-items: center;
  justify-content: center;
  background: rgba(14, 168, 140, 0.2);
  color: var(--accent-light);
  border-radius: 8px;
  font-size: 1.1rem;
  font-weight: 700;
  margin-bottom: 1rem;
}

.feature-card h3 {
  margin: 0 0 0.5rem;
  font-size: 1.1rem;
  font-weight: 600;
}

.feature-card p {
  margin: 0;
  font-size: 0.95rem;
  color: var(--text-muted);
}

/* How it works */
.steps {
  margin: 0;
  padding-left: 1.5rem;
  max-width: 560px;
}

.steps li {
  margin-bottom: 1rem;
  color: var(--text-muted);
}

.steps li strong {
  color: var(--text);
}

/* Use cases */
.use-case-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1.5rem;
}

@media (max-width: 700px) {
  .use-case-grid {
    grid-template-columns: 1fr;
  }
}

.use-case-card {
  padding: 1.5rem;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  transition: transform 0.35s cubic-bezier(0.4, 0, 0.2, 1);
}

.use-case-card:hover {
  transform: translateY(-2px);
}

.use-case-card h3 {
  margin: 0 0 0.5rem;
  font-size: 1.15rem;
  font-weight: 600;
  color: var(--accent-light);
}

.use-case-card p {
  margin: 0;
  font-size: 0.95rem;
  color: var(--text-muted);
}

/* Tech */
.tech .section-lead {
  max-width: 720px;
}

/* CTA section */
.cta-section {
  padding-bottom: 4rem;
}

.cta-box {
  max-width: 480px;
  padding: 2rem;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
}

.code-block {
  margin: 0 0 1rem;
  padding: 1rem;
  background: var(--bg);
  border-radius: 8px;
  overflow-x: auto;
  font-family: var(--font-mono);
  font-size: 0.9rem;
  color: var(--accent);
}

.cta-box p {
  margin: 0 0 1.5rem;
  color: var(--text-muted);
  font-size: 0.95rem;
}

/* Footer */
.site-footer {
  padding: 2rem var(--space);
  border-top: 1px solid var(--border);
  text-align: center;
  color: var(--text-muted);
  font-size: 0.9rem;
}

.site-footer p {
  margin: 0.5rem 0;
}

.footer-links {
  display: flex;
  justify-content: center;
  gap: 1.5rem;
  margin-top: 0.5rem;
}

.footer-links a {
  color: var(--accent-light);
  text-decoration: none;
}

.footer-links a:hover {
  text-decoration: underline;
}

.footer-back {
  display: inline-block;
  margin-top: 1rem;
  color: var(--accent-light) !important;
  text-decoration: none;
  font-weight: 500;
}

.footer-back:hover {
  text-decoration: underline;
}

/* Mobile nav */
@media (max-width: 600px) {
  .nav {
    gap: 0.75rem;
  }

  .nav a:not(.btn) {
    font-size: 0.9rem;
  }

  .hero {
    padding: 3rem 0 4rem;
  }

  .section {
    padding: 2.5rem 0;
  }
}