:root {
  --bg: #FAFAF8;
  --surface: #FFFFFF;
  --primary: #0D9488;
  --primary-dark: #0F766E;
  --accent: #F59E0B;
  --text: #1C1C1C;
  --text-muted: #6B7280;
  --border: #E5E7EB;
  --chat-bg: #F0FDFB;
  --chat-header: #0D9488;
  --student-bubble: #E0F2FE;
  --tutor-bubble: #F0FDFB;
}

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

body {
  font-family: 'Source Sans 3', system-ui, sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

h1, h2, h3, .nav-logo, .hero-headline {
  font-family: 'Nunito', system-ui, sans-serif;
}

/* NAV */
.nav {
  padding: 20px 0;
  border-bottom: 1px solid var(--border);
}
.nav-inner {
  max-width: 1100px;
  margin: 0 auto;
  padding: 0 32px;
}
.nav-logo {
  font-size: 1.25rem;
  font-weight: 800;
  color: var(--primary);
  letter-spacing: -0.02em;
}

/* SECTION LABELS */
.section-label {
  font-family: 'Nunito', system-ui, sans-serif;
  font-size: 0.75rem;
  font-weight: 700;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--primary);
  margin-bottom: 24px;
}

/* HERO */
.hero {
  padding: 80px 0 64px;
  max-width: 1100px;
  margin: 0 auto;
  padding-left: 32px;
  padding-right: 32px;
}
.hero-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 64px;
  align-items: center;
}
.hero-eyebrow {
  font-size: 0.8rem;
  font-weight: 600;
  color: var(--text-muted);
  letter-spacing: 0.06em;
  text-transform: uppercase;
  margin-bottom: 16px;
}
.hero-headline {
  font-size: 2.75rem;
  font-weight: 800;
  line-height: 1.15;
  color: var(--text);
  letter-spacing: -0.03em;
  margin-bottom: 20px;
}
.hero-lede {
  font-size: 1.1rem;
  color: var(--text-muted);
  line-height: 1.65;
}

/* CHAT WIDGET */
.chat-window {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 16px;
  overflow: hidden;
  box-shadow: 0 8px 40px rgba(13, 148, 136, 0.1);
  font-family: 'Source Sans 3', system-ui, sans-serif;
}
.chat-header {
  background: var(--chat-header);
  padding: 14px 20px;
  display: flex;
  align-items: center;
  gap: 10px;
}
.chat-avatar {
  width: 32px;
  height: 32px;
  background: var(--accent);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 800;
  font-size: 0.9rem;
  color: white;
  font-family: 'Nunito', sans-serif;
}
.chat-name {
  color: white;
  font-weight: 600;
  font-size: 0.95rem;
}
.chat-messages {
  padding: 20px 20px 12px;
  display: flex;
  flex-direction: column;
  gap: 12px;
}
.msg { display: flex; }
.msg.student { justify-content: flex-end; }
.bubble {
  max-width: 85%;
  padding: 10px 14px;
  border-radius: 14px;
  font-size: 0.9rem;
  line-height: 1.5;
}
.student .bubble {
  background: var(--student-bubble);
  border-bottom-right-radius: 4px;
}
.tutor .bubble {
  background: var(--tutor-bubble);
  border: 1px solid var(--border);
  border-bottom-left-radius: 4px;
}
.math-q {
  display: inline-block;
  background: #DBEAFE;
  border-radius: 6px;
  padding: 2px 8px;
  font-family: 'Courier New', monospace;
  font-size: 0.85rem;
}
.tutor-tip {
  margin-top: 8px;
  font-size: 0.8rem;
  color: var(--primary);
  background: #CCFBF1;
  border-radius: 6px;
  padding: 6px 10px;
}
.chat-input-bar {
  border-top: 1px solid var(--border);
  padding: 12px 20px;
  display: flex;
  align-items: center;
  gap: 10px;
  background: #FAFAF8;
}
.photo-btn { font-size: 1.2rem; }
.input-hint { font-size: 0.85rem; color: var(--text-muted); }

/* PROCESS */
.process {
  background: var(--surface);
  border-top: 1px solid var(--border);
  border-bottom: 1px solid var(--border);
  padding: 64px 0;
}
.process-inner {
  max-width: 1100px;
  margin: 0 auto;
  padding: 0 32px;
}
.process-steps {
  display: flex;
  align-items: flex-start;
  gap: 20px;
}
.step {
  flex: 1;
  text-align: center;
}
.step-num {
  width: 40px;
  height: 40px;
  background: var(--primary);
  color: white;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 800;
  font-size: 1rem;
  font-family: 'Nunito', sans-serif;
  margin: 0 auto 14px;
}
.step-title {
  font-size: 1rem;
  font-weight: 700;
  color: var(--text);
  margin-bottom: 8px;
  font-family: 'Nunito', sans-serif;
}
.step-desc {
  font-size: 0.875rem;
  color: var(--text-muted);
  line-height: 1.5;
}
.step-arrow {
  font-size: 1.5rem;
  color: var(--border);
  margin-top: 12px;
  flex-shrink: 0;
}

/* FEATURES */
.features {
  padding: 80px 0;
  max-width: 1100px;
  margin: 0 auto;
  padding-left: 32px;
  padding-right: 32px;
}
.features-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 32px;
}
.feature-card {
  padding: 28px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 14px;
  transition: box-shadow 0.2s ease;
}
.feature-card:hover {
  box-shadow: 0 4px 20px rgba(13, 148, 136, 0.08);
}
.feature-icon {
  color: var(--primary);
  margin-bottom: 16px;
}
.feature-title {
  font-size: 1.05rem;
  font-weight: 700;
  font-family: 'Nunito', sans-serif;
  margin-bottom: 8px;
  color: var(--text);
}
.feature-desc {
  font-size: 0.9rem;
  color: var(--text-muted);
  line-height: 1.55;
}

/* DIGEST */
.digest {
  background: var(--surface);
  border-top: 1px solid var(--border);
  border-bottom: 1px solid var(--border);
  padding: 80px 0;
}
.digest-inner {
  max-width: 1100px;
  margin: 0 auto;
  padding: 0 32px;
}
.digest-content {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 64px;
  align-items: center;
}
.digest-headline {
  font-size: 2rem;
  font-weight: 800;
  line-height: 1.25;
  letter-spacing: -0.02em;
  font-family: 'Nunito', sans-serif;
  margin-bottom: 16px;
}
.digest-desc {
  font-size: 1rem;
  color: var(--text-muted);
  line-height: 1.65;
}
.email-mock {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 12px;
  overflow: hidden;
  box-shadow: 0 4px 24px rgba(0,0,0,0.06);
}
.email-header {
  background: #F5F5F4;
  padding: 14px 20px;
  border-bottom: 1px solid var(--border);
}
.email-from {
  font-size: 0.8rem;
  color: var(--text-muted);
  margin-bottom: 2px;
}
.email-subject {
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--text);
}
.email-body {
  padding: 24px 24px 20px;
  font-family: 'Source Sans 3', sans-serif;
}
.email-greeting, .email-intro { margin-bottom: 12px; font-size: 0.95rem; }
.email-stat {
  display: flex;
  align-items: baseline;
  gap: 8px;
  margin-bottom: 10px;
}
.stat-num { font-size: 2rem; font-weight: 800; color: var(--primary); font-family: 'Nunito', sans-serif; }
.stat-label { font-size: 0.9rem; color: var(--text-muted); }
.email-improved, .email-attention {
  border-radius: 8px;
  padding: 10px 14px;
  margin-bottom: 8px;
  font-size: 0.875rem;
}
.email-improved { background: #F0FDF4; border: 1px solid #BBF7D0; }
.email-attention { background: #FFFBEB; border: 1px solid #FDE68A; }
.improved-label, .attention-label {
  font-weight: 700;
  font-size: 0.75rem;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  margin-bottom: 4px;
  color: var(--text-muted);
}

/* OUTCOMES */
.outcomes { padding: 64px 0; }
.outcomes-inner { max-width: 1100px; margin: 0 auto; padding: 0 32px; }
.outcomes-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 0;
  border: 1px solid var(--border);
  border-radius: 16px;
  overflow: hidden;
}
.outcome {
  padding: 40px 36px;
  background: var(--surface);
  text-align: center;
  border-right: 1px solid var(--border);
}
.outcome:last-child { border-right: none; }
.outcome-num {
  font-size: 2.5rem;
  font-weight: 800;
  font-family: 'Nunito', sans-serif;
  color: var(--primary);
  line-height: 1;
  margin-bottom: 4px;
}
.outcome-unit {
  font-size: 0.75rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--text-muted);
  margin-bottom: 12px;
}
.outcome-desc { font-size: 0.9rem; color: var(--text-muted); line-height: 1.5; }

/* CLOSING */
.closing {
  padding: 80px 0 96px;
  text-align: center;
}
.closing-inner { max-width: 700px; margin: 0 auto; padding: 0 32px; }
.closing-headline {
  font-size: 2rem;
  font-weight: 800;
  line-height: 1.3;
  font-family: 'Nunito', sans-serif;
  color: var(--text);
  letter-spacing: -0.02em;
  margin-bottom: 20px;
}
.closing-sub {
  font-size: 1.05rem;
  color: var(--text-muted);
  line-height: 1.65;
}

/* FOOTER */
.footer {
  border-top: 1px solid var(--border);
  padding: 36px 0;
}
.footer-inner { max-width: 1100px; margin: 0 auto; padding: 0 32px; }
.footer-logo {
  font-family: 'Nunito', sans-serif;
  font-size: 1.1rem;
  font-weight: 800;
  color: var(--primary);
  margin-bottom: 6px;
}
.footer-tagline { font-size: 0.875rem; color: var(--text-muted); }

/* RESPONSIVE */
@media (max-width: 900px) {
  .hero-grid { grid-template-columns: 1fr; gap: 40px; }
  .features-grid { grid-template-columns: repeat(2, 1fr); }
  .digest-content { grid-template-columns: 1fr; }
  .outcomes-grid { grid-template-columns: 1fr; }
  .outcome { border-right: none; border-bottom: 1px solid var(--border); }
  .outcome:last-child { border-bottom: none; }
  .hero-headline { font-size: 2.2rem; }
  .process-steps { flex-wrap: wrap; justify-content: center; }
  .step-arrow { display: none; }
}
@media (max-width: 600px) {
  .hero-headline { font-size: 1.8rem; }
  .features-grid { grid-template-columns: 1fr; }
  .closing-headline { font-size: 1.6rem; }
}