:root {
  --bg: #0a0a0f;
  --bg-elevated: #12121a;
  --bg-card: #16161f;
  --fg: #e8e8ed;
  --fg-muted: #8888a0;
  --accent: #00e5a0;
  --accent-dim: rgba(0, 229, 160, 0.12);
  --accent-glow: rgba(0, 229, 160, 0.25);
  --warning: #ffb800;
  --danger: #ff4455;
  --radius: 12px;
  --font-body: 'Space Grotesk', sans-serif;
  --font-mono: 'JetBrains Mono', monospace;
}

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

body {
  background: var(--bg);
  color: var(--fg);
  font-family: var(--font-body);
  font-size: 17px;
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
}

/* ---- HERO ---- */
.hero {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  padding: 80px 24px 60px;
  position: relative;
  overflow: hidden;
}

.hero::before {
  content: '';
  position: absolute;
  top: -40%;
  left: 50%;
  transform: translateX(-50%);
  width: 800px;
  height: 800px;
  background: radial-gradient(circle, var(--accent-glow) 0%, transparent 70%);
  pointer-events: none;
  z-index: 0;
}

.hero-grid {
  position: relative;
  z-index: 1;
  text-align: center;
  max-width: 720px;
}

.hero-label {
  font-family: var(--font-mono);
  font-size: 13px;
  font-weight: 500;
  letter-spacing: 4px;
  color: var(--accent);
  margin-bottom: 24px;
}

.hero h1 {
  font-size: clamp(2.4rem, 6vw, 4.2rem);
  font-weight: 700;
  line-height: 1.15;
  letter-spacing: -0.02em;
  margin-bottom: 24px;
}

.hero .accent {
  color: var(--accent);
}

.hero .lede {
  font-size: 1.15rem;
  color: var(--fg-muted);
  max-width: 540px;
  margin: 0 auto;
  line-height: 1.7;
}

.hero-visual {
  position: relative;
  z-index: 1;
  margin-top: 56px;
  width: 100%;
  max-width: 560px;
}

/* Inbox Preview */
.inbox-preview {
  background: var(--bg-elevated);
  border: 1px solid rgba(255,255,255,0.06);
  border-radius: var(--radius);
  overflow: hidden;
  box-shadow: 0 24px 80px rgba(0,0,0,0.5), 0 0 60px var(--accent-dim);
}

.inbox-header {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 14px 18px;
  background: var(--bg-card);
  border-bottom: 1px solid rgba(255,255,255,0.04);
}

.dot {
  width: 10px;
  height: 10px;
  border-radius: 50%;
}
.dot.green { background: #34d058; }
.dot.yellow { background: #f0c000; }
.dot.red { background: #ff4455; }

.inbox-title {
  font-family: var(--font-mono);
  font-size: 12px;
  color: var(--fg-muted);
  margin-left: 8px;
}

.inbox-item {
  display: grid;
  grid-template-columns: 1fr auto;
  grid-template-rows: auto auto;
  padding: 14px 18px;
  border-bottom: 1px solid rgba(255,255,255,0.03);
  transition: background 0.2s;
}

.inbox-item.unread {
  background: var(--accent-dim);
}

.inbox-item:last-child {
  border-bottom: none;
}

.inbox-from {
  font-family: var(--font-mono);
  font-size: 12px;
  color: var(--accent);
  font-weight: 500;
}

.inbox-time {
  font-size: 12px;
  color: var(--fg-muted);
  text-align: right;
}

.inbox-subj {
  grid-column: 1 / -1;
  font-size: 14px;
  color: var(--fg);
  margin-top: 4px;
}

/* ---- PROBLEM ---- */
.problem {
  padding: 120px 24px;
  background: var(--bg);
}

.problem-inner {
  max-width: 960px;
  margin: 0 auto;
}

.problem h2 {
  font-size: clamp(1.8rem, 4vw, 2.8rem);
  font-weight: 700;
  margin-bottom: 56px;
  text-align: center;
  line-height: 1.2;
}

.strikethrough {
  text-decoration: line-through;
  color: var(--fg-muted);
  text-decoration-color: var(--danger);
  text-decoration-thickness: 3px;
}

.problem-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}

.problem-card {
  background: var(--bg-card);
  border: 1px solid rgba(255,255,255,0.05);
  border-radius: var(--radius);
  padding: 32px 28px;
}

.problem-icon {
  width: 40px;
  height: 40px;
  border-radius: 8px;
  background: rgba(255, 68, 85, 0.12);
  color: var(--danger);
  display: flex;
  align-items: center;
  justify-content: center;
  font-family: var(--font-mono);
  font-size: 20px;
  font-weight: 700;
  margin-bottom: 20px;
}

.problem-card h3 {
  font-size: 1.1rem;
  font-weight: 600;
  margin-bottom: 10px;
}

.problem-card p {
  font-size: 0.92rem;
  color: var(--fg-muted);
  line-height: 1.65;
}

/* ---- FEATURES ---- */
.features {
  padding: 100px 24px;
  background: var(--bg-elevated);
}

.features-inner {
  max-width: 800px;
  margin: 0 auto;
}

.feature-block {
  display: flex;
  gap: 32px;
  align-items: flex-start;
  padding: 40px 0;
  border-bottom: 1px solid rgba(255,255,255,0.04);
}

.feature-block:last-child {
  border-bottom: none;
}

.feature-tag {
  font-family: var(--font-mono);
  font-size: 14px;
  color: var(--accent);
  font-weight: 500;
  min-width: 40px;
  height: 40px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--accent-dim);
  border-radius: 8px;
  flex-shrink: 0;
}

.feature-content h3 {
  font-size: 1.25rem;
  font-weight: 600;
  margin-bottom: 8px;
}

.feature-content p {
  font-size: 0.95rem;
  color: var(--fg-muted);
  line-height: 1.7;
}

/* ---- HOW ---- */
.how {
  padding: 120px 24px;
  background: var(--bg);
}

.how-inner {
  max-width: 720px;
  margin: 0 auto;
  text-align: center;
}

.how h2 {
  font-size: clamp(1.8rem, 4vw, 2.8rem);
  font-weight: 700;
  margin-bottom: 20px;
}

.how-desc {
  font-size: 1.05rem;
  color: var(--fg-muted);
  max-width: 580px;
  margin: 0 auto 48px;
  line-height: 1.7;
}

.code-block {
  background: var(--bg-card);
  border: 1px solid rgba(255,255,255,0.06);
  border-radius: var(--radius);
  overflow: hidden;
  text-align: left;
  box-shadow: 0 16px 48px rgba(0,0,0,0.3);
}

.code-header {
  display: flex;
  align-items: center;
  gap: 6px;
  padding: 12px 16px;
  background: rgba(255,255,255,0.02);
  border-bottom: 1px solid rgba(255,255,255,0.04);
}

.code-dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: rgba(255,255,255,0.12);
}

.code-file {
  font-family: var(--font-mono);
  font-size: 12px;
  color: var(--fg-muted);
  margin-left: 8px;
}

.code-block pre {
  padding: 24px;
  overflow-x: auto;
}

.code-block code {
  font-family: var(--font-mono);
  font-size: 13px;
  line-height: 1.8;
  color: var(--fg);
}

.kw { color: #c792ea; }
.fn { color: #82aaff; }
.str { color: var(--accent); }
.key { color: #f78c6c; }
.num { color: #f78c6c; }

/* ---- CLOSING ---- */
.closing {
  padding: 120px 24px;
  background: var(--bg-elevated);
  text-align: center;
}

.closing-inner {
  max-width: 640px;
  margin: 0 auto;
}

.closing h2 {
  font-size: clamp(1.8rem, 4vw, 2.6rem);
  font-weight: 700;
  line-height: 1.25;
  margin-bottom: 24px;
}

.closing p {
  font-size: 1rem;
  color: var(--fg-muted);
  line-height: 1.7;
  margin-bottom: 16px;
}

.closing-tagline {
  font-size: 1.15rem;
  color: var(--accent);
  font-weight: 600;
  margin-top: 32px;
}

/* ---- FOOTER ---- */
.site-footer {
  padding: 32px 24px;
  border-top: 1px solid rgba(255,255,255,0.04);
  background: var(--bg);
}

.footer-inner {
  max-width: 960px;
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 12px;
  font-size: 13px;
  color: var(--fg-muted);
}

.footer-brand {
  font-weight: 600;
  color: var(--fg);
}

.footer-sep {
  opacity: 0.3;
}

/* ---- RESPONSIVE ---- */
@media (max-width: 768px) {
  .problem-grid {
    grid-template-columns: 1fr;
    gap: 16px;
  }
  
  .feature-block {
    flex-direction: column;
    gap: 16px;
  }
  
  .hero {
    padding: 60px 20px 40px;
    min-height: auto;
  }
  
  .hero-visual {
    margin-top: 40px;
  }
  
  .problem,
  .features,
  .how,
  .closing {
    padding: 80px 20px;
  }

  .code-block code {
    font-size: 11px;
  }

  .inbox-item {
    padding: 12px 14px;
  }

  .inbox-from {
    font-size: 11px;
  }

  .inbox-subj {
    font-size: 13px;
  }
}

@media (max-width: 420px) {
  .hero h1 {
    font-size: 2rem;
  }
  
  .problem h2,
  .how h2,
  .closing h2 {
    font-size: 1.6rem;
  }
}