:root {
  --bg: #f6f7f3;
  --bg-alt: #eceee7;
  --surface: #ffffff;
  --text: #121a16;
  --muted: #4d5a53;
  --line: #d6dacf;
  --accent: #0f7a52;
  --accent-ink: #ffffff;
  --accent-soft: #c9ecd9;
  --radius: 14px;
  --font: ui-sans-serif, system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  --mono: ui-monospace, "SF Mono", Menlo, Consolas, monospace;
  --gold: #8a5a00;
  --gold-soft: rgba(240, 178, 75, 0.22);
  --warn: #b4462f;
  --warn-soft: rgba(180, 70, 47, 0.1);
  --pencil: #c4331a;
  --ink: #0c1411;
  --ink-2: #14231c;
  --ink-text: #eef3ef;
  --ink-muted: #8fa399;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #0c1411;
    --bg-alt: #111b17;
    --surface: #15211c;
    --text: #eef3ef;
    --muted: #a3b2a9;
    --line: #25352d;
    --accent: #5fd6a0;
    --accent-ink: #06130d;
    --accent-soft: #1d3a2e;
    --gold: #f0b24b;
    --gold-soft: rgba(240, 178, 75, 0.16);
    --warn: #f0907a;
    --warn-soft: rgba(240, 144, 122, 0.12);
    --pencil: #ff7a5c;
    --ink: #070d0a;
    --ink-2: #101b16;
  }
}

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

html {
  scroll-behavior: smooth;
  scroll-padding-top: 4.5rem;
  -webkit-text-size-adjust: 100%;
}

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font: 1rem/1.6 var(--font);
  -webkit-font-smoothing: antialiased;
}

h1,
h2,
h3 {
  line-height: 1.15;
  letter-spacing: -0.02em;
  margin: 0 0 0.6em;
}

h1 {
  font-size: clamp(2.4rem, 7vw, 4.2rem);
  letter-spacing: -0.035em;
}

h2 {
  font-size: clamp(1.7rem, 4vw, 2.4rem);
}

h3 {
  font-size: 1.15rem;
}

p {
  margin: 0 0 1em;
}

a {
  color: inherit;
}

:focus-visible {
  outline: 3px solid var(--accent);
  outline-offset: 3px;
  border-radius: 6px;
}

.wrap {
  width: 100%;
  max-width: 68rem;
  margin: 0 auto;
  padding: 0 max(1rem, env(safe-area-inset-right)) 0 max(1rem, env(safe-area-inset-left));
}

.narrow {
  max-width: 44rem;
}

.center {
  text-align: center;
}

.skip {
  position: absolute;
  left: -999px;
  top: 0.5rem;
  background: var(--accent);
  color: var(--accent-ink);
  padding: 0.5rem 0.9rem;
  border-radius: 8px;
  z-index: 10;
}

.skip:focus {
  left: 0.5rem;
}

/* Header */
.site-header {
  position: sticky;
  top: 0;
  z-index: 5;
  background: color-mix(in srgb, var(--bg) 88%, transparent);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--line);
}

.site-bar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  min-height: 3.75rem;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 0.6rem;
  font-weight: 800;
  letter-spacing: -0.02em;
  text-decoration: none;
}

.mark {
  width: 28px;
  height: 28px;
}

.mark-bg {
  fill: var(--accent);
}

.mark-path {
  fill: none;
  stroke: var(--accent-ink);
  stroke-width: 3;
  stroke-linecap: round;
  stroke-linejoin: round;
}

nav {
  display: flex;
  align-items: center;
  gap: 1.25rem;
  font-size: 0.95rem;
}

nav a:not(.btn) {
  text-decoration: none;
  color: var(--muted);
}

nav a:not(.btn):hover {
  color: var(--text);
}

@media (max-width: 760px) {
  nav a:not(.btn) {
    display: none;
  }
}

/* Buttons */
.btn {
  display: inline-block;
  background: var(--accent);
  color: var(--accent-ink);
  font-weight: 700;
  text-decoration: none;
  padding: 0.8rem 1.4rem;
  border-radius: 999px;
  border: 2px solid var(--accent);
  transition: transform 0.15s ease, filter 0.15s ease;
}

button.btn { font: inherit; font-weight: 700; cursor: pointer; }
.btn[hidden] { display: none; }

.btn:hover {
  filter: brightness(1.06);
  transform: translateY(-1px);
}

.btn-small {
  padding: 0.45rem 1rem;
  font-size: 0.9rem;
}

.btn-large {
  padding: 1rem 2rem;
  font-size: 1.1rem;
}

.btn-ghost {
  background: transparent;
  color: var(--text);
  border-color: var(--line);
}

/* Hero */
.hero {
  padding: clamp(2.5rem, 8vw, 6rem) 0 clamp(2rem, 6vw, 4.5rem);
}

.hero-grid {
  display: grid;
  gap: 3rem;
  align-items: center;
}

@media (min-width: 960px) {
  .hero-grid {
    grid-template-columns: minmax(0, 1fr) 400px;
  }
}

.hero-demo {
  display: flex;
  justify-content: center;
  min-width: 0;
}

.eyebrow {
  color: var(--accent);
  font-weight: 700;
  font-size: 0.85rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  margin-bottom: 0.9rem;
}

.lead {
  font-size: clamp(1.05rem, 2.2vw, 1.25rem);
  color: var(--muted);
  max-width: 36rem;
}

.cta-row {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
  margin: 1.75rem 0 1rem;
}

.fine {
  color: var(--muted);
  font-size: 0.9rem;
}

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }

  .btn {
    transition: none;
  }
}

/* Sections */
.section {
  padding: clamp(3rem, 8vw, 5.5rem) 0;
}

.section.alt {
  background: var(--bg-alt);
}

.loop {
  list-style: none;
  counter-reset: step;
  display: grid;
  gap: 1rem;
  padding: 0;
  margin: 2rem 0 0;
}

@media (min-width: 760px) {
  .loop {
    grid-template-columns: repeat(auto-fit, minmax(11rem, 1fr));
  }
}

.loop li {
  counter-increment: step;
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 1.25rem;
}

.loop li::before {
  content: counter(step);
  display: grid;
  place-items: center;
  width: 2rem;
  height: 2rem;
  margin-bottom: 0.9rem;
  border-radius: 50%;
  background: var(--accent);
  color: var(--accent-ink);
  font-weight: 800;
}

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

/* arrows between the "How it works" steps */
.loop li {
  position: relative;
}

.loop li:not(:last-child)::after {
  content: "";
  position: absolute;
  z-index: 2;
  width: 26px;
  height: 26px;
  border-radius: 50%;
  background: var(--bg) url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24' fill='none' stroke='%230f7a52' stroke-width='2.2' stroke-linecap='round' stroke-linejoin='round'%3E%3Cpath d='M5 12h14M13 6l6 6-6 6'/%3E%3C/svg%3E") center / 13px no-repeat;
  border: 1px solid var(--line);
}

@media (prefers-color-scheme: dark) {
  .loop li:not(:last-child)::after {
    background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24' fill='none' stroke='%235fd6a0' stroke-width='2.2' stroke-linecap='round' stroke-linejoin='round'%3E%3Cpath d='M5 12h14M13 6l6 6-6 6'/%3E%3C/svg%3E");
  }
}

@media (min-width: 1000px) {
  .loop {
    grid-template-columns: repeat(5, 1fr);
  }

  .loop li:not(:last-child)::after {
    right: -21px;
    top: 50%;
    transform: translateY(-50%);
  }
}

@media (max-width: 759px) {
  .loop li:not(:last-child)::after {
    left: 50%;
    bottom: -21px;
    transform: translateX(-50%) rotate(90deg);
  }
}

@media (min-width: 760px) and (max-width: 999px) {
  .loop li:not(:last-child)::after {
    display: none;
  }
}

.worlds {
  display: grid;
  gap: 1rem;
  margin-top: 2rem;
  grid-template-columns: repeat(auto-fit, minmax(15.5rem, 1fr));
}

.world {
  --wc: var(--accent);
  position: relative;
  overflow: hidden;
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: 22px;
  padding: 2.6rem 1.25rem 1.25rem;
  box-shadow: 0 1px 2px rgba(11, 22, 24, 0.06), 0 2px 8px rgba(11, 22, 24, 0.05);
  transition: transform 0.2s ease, box-shadow 0.2s ease, border-color 0.2s ease;
}

.world::before {
  content: "";
  position: absolute;
  inset: 0 0 auto 0;
  height: 3px;
  background: var(--wc);
}

.world:hover {
  transform: translateY(-3px);
  border-color: var(--wc);
  box-shadow: 0 8px 26px rgba(11, 22, 24, 0.12);
}

.world--listening { --wc: #17c4b4; }
.world--reading { --wc: #3fa9f5; }
.world--writing { --wc: #f0b24b; }
.world--speaking { --wc: #e0685a; }

.world h3 {
  font-size: 1.95rem;
  letter-spacing: -0.03em;
  margin: 0 0 0.4rem;
}

.world-tag {
  color: var(--muted);
  font-size: 0.95rem;
  line-height: 1.5;
  margin: 0;
}

@media (min-width: 640px) {
  .world-tag {
    min-height: 4.5em;
  }
}

.world-badge {
  position: absolute;
  top: 0.95rem;
  right: 0.95rem;
  font: 600 0.68rem/1 var(--mono);
  letter-spacing: 0.06em;
  padding: 0.35rem 0.6rem;
  border-radius: 999px;
  background: var(--gold-soft);
  color: var(--gold);
}

.modes {
  list-style: none;
  margin: 1.1rem 0 0;
  padding: 0;
  display: grid;
  gap: 0.5rem;
}

.modes li {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 0.75rem;
  padding: 0.65rem 0.8rem;
  border-radius: 12px;
  background: var(--bg-alt);
}

.modes .nm {
  font-weight: 650;
  font-size: 0.93rem;
  line-height: 1.25;
}

.modes .dsc {
  color: var(--muted);
  font-size: 0.76rem;
  line-height: 1.3;
  text-align: right;
  max-width: 52%;
}

.ticks {
  list-style: none;
  padding: 0;
  margin: 1.5rem 0 0;
  display: grid;
  gap: 0.75rem;
}

.ticks li {
  position: relative;
  padding-left: 2rem;
}

.ticks li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0.35em;
  width: 1.1rem;
  height: 1.1rem;
  border-radius: 50%;
  background: var(--accent);
  -webkit-mask: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 16 16'%3E%3Cpath d='M3 8.5l3.2 3L13 4.5' fill='none' stroke='black' stroke-width='2.2' stroke-linecap='round' stroke-linejoin='round'/%3E%3C/svg%3E") center / 100% no-repeat;
  mask: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 16 16'%3E%3Cpath d='M3 8.5l3.2 3L13 4.5' fill='none' stroke='black' stroke-width='2.2' stroke-linecap='round' stroke-linejoin='round'/%3E%3C/svg%3E") center / 100% no-repeat;
}

/* FAQ */
details {
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 0 1.25rem;
  margin-top: 0.75rem;
}

summary {
  cursor: pointer;
  font-weight: 700;
  padding: 1rem 0;
  list-style-position: outside;
}

details p {
  color: var(--muted);
  padding-bottom: 0.25rem;
}

/* CTA + footer */
.cta p {
  color: var(--muted);
  margin-bottom: 1.75rem;
}

.site-footer {
  border-top: 1px solid var(--line);
  font-size: 0.9rem;
  padding: 0.5rem 0;
}

.site-footer .site-bar {
  flex-wrap: wrap;
}

.muted {
  color: var(--muted);
}