/* =====================================================
   SellerOS — Landing
   Design tokens: Geist + monochrome + indigo accent
   ===================================================== */

:root {
  /* color */
  --bg: #ffffff;
  --bg-soft: #fafafa;
  --bg-muted: #f5f5f5;
  --bg-dark: #0a0a0a;
  --border: rgba(10, 10, 10, 0.08);
  --border-strong: rgba(10, 10, 10, 0.14);
  --text-1: #0a0a0a;
  --text-2: #525252;
  --text-3: #a3a3a3;
  --text-inv: #fafafa;
  --text-inv-2: #a3a3a3;

  --accent: #4f46e5;
  --accent-hover: #4338ca;
  --accent-soft: #eef2ff;
  --accent-line: #c7d2fe;

  --pos: #059669;
  --pos-soft: #ecfdf5;
  --neg: #dc2626;

  /* layout */
  --maxw: 1180px;
  --pad-x: clamp(20px, 5vw, 48px);
  --section-y: clamp(80px, 12vw, 144px);

  /* radii */
  --r-sm: 6px;
  --r-md: 10px;
  --r-lg: 16px;
  --r-xl: 22px;

  /* shadow */
  --sh-1: 0 1px 2px rgba(10, 10, 10, 0.04);
  --sh-2: 0 4px 12px rgba(10, 10, 10, 0.05), 0 1px 2px rgba(10, 10, 10, 0.04);
  --sh-3: 0 12px 32px rgba(10, 10, 10, 0.08), 0 4px 12px rgba(10, 10, 10, 0.04);

  /* type */
  --f-sans: 'Geist', -apple-system, BlinkMacSystemFont, 'Segoe UI', system-ui, sans-serif;
  --f-mono: 'Geist Mono', ui-monospace, 'SF Mono', Menlo, monospace;
}

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

html {
  scroll-behavior: smooth;
}

body {
  font-family: var(--f-sans);
  font-feature-settings: 'cv11', 'ss01', 'ss03';
  font-size: 16px;
  line-height: 1.5;
  color: var(--text-1);
  background: var(--bg);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  text-rendering: optimizeLegibility;
}

a {
  color: inherit;
  text-decoration: none;
}

img,
svg {
  display: block;
  max-width: 100%;
}

::selection {
  background: var(--accent);
  color: var(--text-inv);
}

/* layout primitives */
.container {
  width: 100%;
  max-width: var(--maxw);
  margin: 0 auto;
  padding-left: var(--pad-x);
  padding-right: var(--pad-x);
}

/* ============== NAV ============== */
.nav {
  position: sticky;
  top: 0;
  z-index: 50;
  background: rgba(255, 255, 255, 0.78);
  backdrop-filter: saturate(180%) blur(14px);
  -webkit-backdrop-filter: saturate(180%) blur(14px);
  border-bottom: 1px solid transparent;
  transition: border-color 0.2s ease;
}

.nav.scrolled {
  border-color: var(--border);
}

.nav-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 64px;
}

.logo {
  display: flex;
  align-items: center;
  gap: 10px;
  font-weight: 600;
  font-size: 16px;
  letter-spacing: -0.01em;
}

.logo-mark {
  width: 26px;
  height: 26px;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 28px;
}

.nav-links a {
  font-size: 14px;
  color: var(--text-2);
  transition: color 0.15s ease;
}

.nav-links a:hover {
  color: var(--text-1);
}

@media (max-width: 720px) {
  .nav-links {
    display: none;
  }
}

/* ============== BUTTONS ============== */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  height: 40px;
  padding: 0 18px;
  border-radius: var(--r-md);
  font-family: inherit;
  font-size: 14px;
  font-weight: 500;
  letter-spacing: -0.005em;
  border: 1px solid transparent;
  cursor: pointer;
  transition:
    background 0.15s ease,
    border-color 0.15s ease,
    transform 0.1s ease,
    box-shadow 0.15s ease;
  white-space: nowrap;
}

.btn:active {
  transform: translateY(0.5px);
}

.btn-primary {
  background: var(--text-1);
  color: var(--text-inv);
}

.btn-primary:hover {
  background: #1f1f1f;
}

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

.btn-secondary:hover {
  background: var(--bg-soft);
  border-color: var(--text-1);
}

.btn-ghost {
  background: transparent;
  color: var(--text-1);
  height: 36px;
  padding: 0 14px;
}

.btn-ghost:hover {
  background: var(--bg-soft);
}

.btn-lg {
  height: 52px;
  padding: 0 26px;
  font-size: 15px;
  border-radius: var(--r-md);
}

.btn .arrow {
  width: 14px;
  height: 14px;
  transition: transform 0.15s ease;
}

.btn:hover .arrow {
  transform: translateX(2px);
}

/* ============== HERO ============== */
.hero {
  position: relative;
  padding-top: clamp(48px, 8vw, 96px);
  padding-bottom: var(--section-y);
  overflow: hidden;
}

.hero::before {
  content: '';
  position: absolute;
  inset: 0;
  background-image:
    radial-gradient(circle at 1px 1px, rgba(10, 10, 10, 0.06) 1px, transparent 0);
  background-size: 28px 28px;
  -webkit-mask-image: radial-gradient(ellipse 72% 60% at 50% 30%, black 30%, transparent 70%);
  mask-image: radial-gradient(ellipse 72% 60% at 50% 30%, black 30%, transparent 70%);
  pointer-events: none;
}

.hero-grid {
  display: grid;
  grid-template-columns: 1.05fr 0.95fr;
  gap: clamp(40px, 6vw, 80px);
  align-items: center;
  position: relative;
}

@media (max-width: 920px) {
  .hero-grid {
    grid-template-columns: 1fr;
  }
  .hero-visual {
    order: -1;
  }
}

.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 6px 12px;
  background: var(--bg-soft);
  border: 1px solid var(--border);
  border-radius: 999px;
  font-size: 13px;
  color: var(--text-2);
  margin-bottom: 24px;
}

.eyebrow-dot {
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--accent);
  box-shadow: 0 0 0 3px var(--accent-soft);
}

.hero h1 {
  font-size: clamp(40px, 6.4vw, 76px);
  font-weight: 600;
  line-height: 1.02;
  letter-spacing: -0.035em;
  color: var(--text-1);
  margin-bottom: 24px;
}

.hero h1 em {
  font-style: normal;
  background: linear-gradient(135deg, var(--accent) 0%, #7c6fff 100%);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
  font-weight: 600;
}

.lede {
  font-size: clamp(16px, 1.3vw, 18px);
  line-height: 1.55;
  color: var(--text-2);
  max-width: 540px;
  margin-bottom: 32px;
}

.cta-row {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-bottom: 20px;
}

.trustline {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 10px;
  font-size: 13px;
  color: var(--text-3);
}

.trust-sep {
  width: 3px;
  height: 3px;
  border-radius: 50%;
  background: var(--text-3);
}

/* hero visual */
.hero-visual {
  position: relative;
  aspect-ratio: 1 / 1;
  max-width: 560px;
  margin-left: auto;
  width: 100%;
}

.hero-visual svg {
  width: 100%;
  height: 100%;
}

/* ============== STAT STRIP ============== */
.stats {
  padding: 32px 0;
  border-top: 1px solid var(--border);
  border-bottom: 1px solid var(--border);
  background: var(--bg-soft);
}

.stat-row {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 32px;
}

@media (max-width: 720px) {
  .stat-row {
    grid-template-columns: repeat(2, 1fr);
    gap: 24px;
  }
}

.stat {
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.stat-num {
  font-family: var(--f-mono);
  font-size: 24px;
  font-weight: 500;
  letter-spacing: -0.02em;
  color: var(--text-1);
  font-feature-settings: 'tnum';
}

.stat-label {
  font-size: 13px;
  color: var(--text-2);
  line-height: 1.4;
}

/* ============== SECTION COMMON ============== */
.section {
  padding: var(--section-y) 0;
}

.section-head {
  max-width: 720px;
  margin-bottom: clamp(48px, 6vw, 72px);
}

.section-tag {
  display: inline-block;
  font-family: var(--f-mono);
  font-size: 12px;
  font-weight: 500;
  letter-spacing: 0.06em;
  color: var(--accent);
  text-transform: uppercase;
  margin-bottom: 16px;
}

.section-title {
  font-size: clamp(30px, 4vw, 48px);
  font-weight: 600;
  line-height: 1.08;
  letter-spacing: -0.025em;
  color: var(--text-1);
}

.section-lede {
  margin-top: 20px;
  font-size: 17px;
  line-height: 1.55;
  color: var(--text-2);
  max-width: 580px;
}

/* ============== PROBLEM ============== */
.problem-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1px;
  background: var(--border);
  border: 1px solid var(--border);
  border-radius: var(--r-lg);
  overflow: hidden;
}

@media (max-width: 820px) {
  .problem-grid {
    grid-template-columns: 1fr;
  }
}

.problem-card {
  background: var(--bg);
  padding: 36px 32px;
  display: flex;
  flex-direction: column;
  gap: 14px;
}

.problem-num {
  font-family: var(--f-mono);
  font-size: 12px;
  font-weight: 500;
  letter-spacing: 0.06em;
  color: var(--text-3);
}

.problem-card h3 {
  font-size: 19px;
  font-weight: 600;
  letter-spacing: -0.015em;
  line-height: 1.3;
  color: var(--text-1);
}

.problem-card p {
  font-size: 15px;
  line-height: 1.55;
  color: var(--text-2);
}

/* ============== FEATURES ============== */
.features-grid {
  display: grid;
  grid-template-columns: repeat(6, 1fr);
  gap: 20px;
}

.feature-card {
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: var(--r-lg);
  padding: 32px;
  display: flex;
  flex-direction: column;
  gap: 16px;
  transition:
    border-color 0.2s ease,
    box-shadow 0.2s ease,
    transform 0.2s ease;
}

.feature-card:hover {
  border-color: var(--border-strong);
  box-shadow: var(--sh-2);
  transform: translateY(-2px);
}

.feature-card--wide {
  grid-column: span 4;
  padding: 36px;
}

.feature-card--narrow {
  grid-column: span 2;
}

.feature-card--half {
  grid-column: span 3;
}

@media (max-width: 820px) {
  .features-grid {
    grid-template-columns: 1fr;
  }
  .feature-card--wide,
  .feature-card--narrow,
  .feature-card--half {
    grid-column: span 1;
  }
}

.feature-icon {
  width: 40px;
  height: 40px;
  border-radius: var(--r-md);
  background: var(--accent-soft);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--accent);
}

.feature-icon svg {
  width: 22px;
  height: 22px;
}

.feature-card h3 {
  font-size: 19px;
  font-weight: 600;
  letter-spacing: -0.015em;
  line-height: 1.3;
  color: var(--text-1);
}

.feature-card p {
  font-size: 15px;
  line-height: 1.55;
  color: var(--text-2);
}

.feature-proof {
  margin-top: auto;
  padding-top: 16px;
  font-family: var(--f-mono);
  font-size: 12px;
  color: var(--text-3);
  letter-spacing: -0.005em;
  border-top: 1px solid var(--border);
}

/* feature card visual (inside wide card) */
.feature-visual {
  margin-top: 8px;
  background: var(--bg-soft);
  border: 1px solid var(--border);
  border-radius: var(--r-md);
  padding: 20px;
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.fv-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  padding: 8px 0;
  border-bottom: 1px solid var(--border);
}

.fv-row:last-child {
  border-bottom: none;
}

.fv-label {
  font-size: 13px;
  color: var(--text-2);
}

.fv-val {
  font-family: var(--f-mono);
  font-size: 13px;
  font-weight: 500;
  color: var(--text-1);
  font-feature-settings: 'tnum';
}

.fv-val.neg {
  color: var(--neg);
}

.fv-val.pos {
  color: var(--pos);
}

/* ============== HOW ============== */
.how {
  background: var(--bg-soft);
  border-top: 1px solid var(--border);
  border-bottom: 1px solid var(--border);
}

.how-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 32px;
  position: relative;
}

@media (max-width: 820px) {
  .how-grid {
    grid-template-columns: 1fr;
  }
}

.how-step {
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.how-step-num {
  display: flex;
  align-items: center;
  gap: 12px;
}

.how-step-num span {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 32px;
  height: 32px;
  border-radius: 50%;
  background: var(--text-1);
  color: var(--text-inv);
  font-family: var(--f-mono);
  font-size: 13px;
  font-weight: 500;
}

.how-step-num::after {
  content: '';
  flex: 1;
  height: 1px;
  background: var(--border-strong);
  background-image: linear-gradient(to right, var(--border-strong) 50%, transparent 50%);
  background-size: 8px 1px;
  background-repeat: repeat-x;
}

.how-step h3 {
  font-size: 20px;
  font-weight: 600;
  letter-spacing: -0.02em;
  line-height: 1.25;
  color: var(--text-1);
}

.how-step p {
  font-size: 15px;
  line-height: 1.55;
  color: var(--text-2);
}

/* ============== ANTI (dark) ============== */
.anti {
  background: var(--bg-dark);
  color: var(--text-inv);
  position: relative;
  overflow: hidden;
}

.anti::before {
  content: '';
  position: absolute;
  inset: 0;
  background-image:
    radial-gradient(circle at 1px 1px, rgba(255, 255, 255, 0.06) 1px, transparent 0);
  background-size: 24px 24px;
  -webkit-mask-image: radial-gradient(ellipse 80% 70% at 50% 50%, black 20%, transparent 70%);
  mask-image: radial-gradient(ellipse 80% 70% at 50% 50%, black 20%, transparent 70%);
  pointer-events: none;
}

.anti .container {
  position: relative;
}

.anti .section-title {
  color: var(--text-inv);
}

.anti .section-tag {
  color: var(--accent-line);
}

.anti .section-lede {
  color: var(--text-inv-2);
}

.anti-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
  margin-top: clamp(40px, 5vw, 56px);
}

@media (max-width: 820px) {
  .anti-grid {
    grid-template-columns: 1fr;
  }
}

.anti-card {
  background: rgba(255, 255, 255, 0.03);
  border: 1px solid rgba(255, 255, 255, 0.08);
  border-radius: var(--r-lg);
  padding: 32px;
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.anti-card-head {
  display: flex;
  align-items: center;
  gap: 10px;
  font-family: var(--f-mono);
  font-size: 12px;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--text-inv-2);
}

.anti-strike {
  position: relative;
  display: inline-block;
  color: var(--text-inv);
}

.anti-strike::after {
  content: '';
  position: absolute;
  left: -2px;
  right: -2px;
  top: 50%;
  height: 1.5px;
  background: var(--accent);
  transform: rotate(-3deg);
}

.anti-card h3 {
  font-size: 22px;
  font-weight: 600;
  letter-spacing: -0.02em;
  line-height: 1.25;
  color: var(--text-inv);
}

.anti-card p {
  font-size: 15px;
  line-height: 1.55;
  color: var(--text-inv-2);
}

/* ============== FAQ ============== */
.faq-list {
  border-top: 1px solid var(--border);
  max-width: 820px;
}

.faq-item {
  border-bottom: 1px solid var(--border);
  padding: 24px 0;
}

.faq-item summary {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
  font-size: 17px;
  font-weight: 500;
  letter-spacing: -0.01em;
  color: var(--text-1);
  cursor: pointer;
  list-style: none;
  transition: color 0.15s ease;
}

.faq-item summary::-webkit-details-marker {
  display: none;
}

.faq-item summary::after {
  content: '';
  flex-shrink: 0;
  width: 16px;
  height: 16px;
  background-image: url("data:image/svg+xml;utf8,<svg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 16 16' fill='none' stroke='%230a0a0a' stroke-width='1.5'><path d='M3 6l5 5 5-5'/></svg>");
  background-repeat: no-repeat;
  background-position: center;
  transition: transform 0.2s ease;
}

.faq-item[open] summary::after {
  transform: rotate(180deg);
}

.faq-item summary:hover {
  color: var(--accent);
}

.faq-item p {
  margin-top: 14px;
  font-size: 15px;
  line-height: 1.6;
  color: var(--text-2);
  max-width: 680px;
}

/* ============== PRICING TEASER ============== */
.pricing-teaser {
  background: var(--bg-soft);
  border-top: 1px solid var(--border);
  border-bottom: 1px solid var(--border);
}

.pricing-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 32px;
  flex-wrap: wrap;
}

.pricing-text h3 {
  font-size: 24px;
  font-weight: 600;
  letter-spacing: -0.02em;
  color: var(--text-1);
  margin-bottom: 6px;
}

.pricing-text p {
  font-size: 15px;
  color: var(--text-2);
}

/* ============== CTA FINAL ============== */
.cta-final {
  text-align: center;
  padding: clamp(80px, 12vw, 144px) 0;
  position: relative;
  overflow: hidden;
}

.cta-final::before {
  content: '';
  position: absolute;
  inset: 0;
  background-image:
    radial-gradient(circle at 1px 1px, rgba(79, 70, 229, 0.08) 1px, transparent 0);
  background-size: 32px 32px;
  -webkit-mask-image: radial-gradient(ellipse 60% 60% at 50% 50%, black 0%, transparent 70%);
  mask-image: radial-gradient(ellipse 60% 60% at 50% 50%, black 0%, transparent 70%);
  pointer-events: none;
}

.cta-final .container {
  position: relative;
}

.cta-final h2 {
  font-size: clamp(32px, 4.5vw, 56px);
  font-weight: 600;
  letter-spacing: -0.03em;
  line-height: 1.05;
  margin-bottom: 16px;
  color: var(--text-1);
}

.cta-final p {
  font-size: 17px;
  color: var(--text-2);
  margin-bottom: 36px;
  max-width: 560px;
  margin-left: auto;
  margin-right: auto;
}

/* ============== FOOTER ============== */
.footer {
  border-top: 1px solid var(--border);
  padding: 32px 0;
  background: var(--bg);
}

.footer-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
  flex-wrap: wrap;
  font-size: 13px;
  color: var(--text-3);
}

.footer-links {
  display: flex;
  align-items: center;
  gap: 20px;
}

.footer-links a {
  color: var(--text-2);
  transition: color 0.15s ease;
}

.footer-links a:hover {
  color: var(--text-1);
}

/* ============== UTILS ============== */
.fade-in {
  opacity: 0;
  transform: translateY(8px);
  animation: fadeIn 0.6s ease forwards;
}

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

@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: 0.001ms !important;
    transition-duration: 0.001ms !important;
  }
  html {
    scroll-behavior: auto;
  }
}