/* ============================================================
   VocabLearn — shared stylesheet (index.html + privacy.html)
   No external assets. System fonts only.
   ============================================================ */

/* ---------- Design tokens ---------- */
:root {
  /* Brand */
  --green:        #16A34A;
  --green-dark:   #0A5C2A;
  --green-pale:   #DCFCE7;
  --green-wash:   #F0FDF4;
  --forest:       #0A1E0C;

  /* Surfaces & text (light) */
  --bg:           #FAFAF5;
  --surface:      #FFFFFF;
  --text:         #111827;
  --muted:        #6B7280;
  --border:       #E5E7EB;

  /* Derived */
  --shadow-sm:    0 1px 2px rgba(17, 24, 39, 0.05);
  --shadow-md:    0 6px 24px rgba(10, 30, 12, 0.08);
  --shadow-lg:    0 16px 48px rgba(10, 30, 12, 0.12);
  --tint:         var(--green-wash);
  --chip:         var(--green-pale);

  /* Type */
  --font-display: Charter, "Bitstream Charter", "Iowan Old Style",
                  Georgia, Cambria, "Times New Roman", serif;
  --font-body:    system-ui, -apple-system, "Segoe UI", Roboto,
                  "Helvetica Neue", Arial, sans-serif;

  /* Motion */
  --ease-out:     cubic-bezier(0, 0, 0.2, 1);
  --ease-spring:  cubic-bezier(0.34, 1.56, 0.64, 1);

  /* Layout */
  --radius:       16px;
  --radius-sm:    12px;
  --radius-lg:    20px;
  --max-w:        1080px;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg:        #0E1512;
    --surface:   #17201C;
    --text:      #ECF1ED;
    --muted:     #8A968E;
    --border:    #2A352F;
    --tint:      #14201A;
    --chip:      #123B22;
    --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.4);
    --shadow-md: 0 6px 24px rgba(0, 0, 0, 0.45);
    --shadow-lg: 0 16px 48px rgba(0, 0, 0, 0.55);
  }
}

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

html {
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
}

body {
  margin: 0;
  font-family: var(--font-body);
  font-size: 1.0625rem;
  line-height: 1.65;
  color: var(--text);
  background: var(--bg);
  overflow-x: hidden;
}

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

h1, h2, h3 {
  font-family: var(--font-display);
  font-weight: 700;
  line-height: 1.15;
  letter-spacing: -0.015em;
  margin: 0 0 0.5em;
  text-wrap: balance;
}

h1 { font-size: clamp(2.2rem, 5.5vw, 3.4rem); }
h2 { font-size: clamp(1.6rem, 3.5vw, 2.2rem); }
h3 { font-size: 1.15rem; font-family: var(--font-body); font-weight: 650; letter-spacing: 0; }

p { margin: 0 0 1em; }

a {
  color: var(--green-dark);
  text-decoration-thickness: 1px;
  text-underline-offset: 3px;
}
@media (prefers-color-scheme: dark) {
  a { color: #4ADE80; }
}
a:hover { color: var(--green); }

:focus-visible {
  outline: 3px solid var(--green);
  outline-offset: 3px;
  border-radius: 4px;
}

::selection { background: var(--green-pale); color: var(--forest); }

.container {
  max-width: var(--max-w);
  margin-inline: auto;
  padding-inline: clamp(1.1rem, 4vw, 2rem);
}

.section { padding-block: clamp(3.5rem, 8vw, 6rem); }

.section-head {
  max-width: 40rem;
  margin-bottom: clamp(2rem, 5vw, 3rem);
}

.eyebrow {
  display: inline-block;
  font-size: 0.8rem;
  font-weight: 700;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--green);
  margin-bottom: 0.6rem;
}

.lead { color: var(--muted); font-size: 1.1rem; }

/* ---------- Header ---------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  background: color-mix(in srgb, var(--bg) 85%, transparent);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--border);
}

.nav {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  min-height: 64px;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 0.6rem;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 1.25rem;
  color: var(--text);
  text-decoration: none;
}
.brand:hover { color: var(--text); }

.brand-mark {
  width: 36px;
  height: 36px;
  border-radius: 10px;
  background: var(--forest);
  display: grid;
  place-items: center;
  flex-shrink: 0;
}
.brand-mark svg { width: 26px; height: 26px; }

.nav-links {
  display: flex;
  align-items: center;
  gap: clamp(0.8rem, 2.5vw, 1.6rem);
  list-style: none;
  margin: 0;
  padding: 0;
}
.nav-links a {
  color: var(--muted);
  text-decoration: none;
  font-size: 0.95rem;
  font-weight: 500;
  transition: color 150ms var(--ease-out);
}
.nav-links a:hover { color: var(--text); }

@media (max-width: 640px) {
  .nav-links li.hide-sm { display: none; }
}

/* ---------- Buttons ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 0.6rem;
  padding: 0.85rem 1.5rem;
  border-radius: 999px;
  font-weight: 650;
  font-size: 1rem;
  text-decoration: none;
  border: none;
  cursor: pointer;
  transition: transform 150ms var(--ease-out), box-shadow 150ms var(--ease-out);
}

.btn-primary {
  background: var(--green);
  color: var(--forest); /* AA contrast on brand green */
  box-shadow: var(--shadow-md);
}
.btn-primary:hover {
  color: var(--forest);
  transform: translateY(-2px);
  box-shadow: var(--shadow-lg);
}
.btn-primary:active { transform: translateY(0) scale(0.98); }

/* ---------- Hero ---------- */
.hero {
  position: relative;
  padding-block: clamp(3.5rem, 9vw, 7rem);
  background:
    radial-gradient(60rem 30rem at 85% -10%, var(--tint) 0%, transparent 60%),
    var(--bg);
}

.hero-grid {
  display: grid;
  grid-template-columns: 1.15fr 0.85fr;
  gap: clamp(2rem, 6vw, 4.5rem);
  align-items: center;
}
@media (max-width: 820px) {
  .hero-grid { grid-template-columns: 1fr; }
}

.hero-badges {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  margin-bottom: 1.2rem;
}
.badge {
  font-size: 0.8rem;
  font-weight: 600;
  color: var(--green-dark);
  background: var(--chip);
  border-radius: 999px;
  padding: 0.3rem 0.85rem;
}
@media (prefers-color-scheme: dark) {
  .badge { color: var(--green-pale); }
}

.hero h1 { margin-bottom: 0.4em; }
.hero .promise { max-width: 32ch; }
.hero .support {
  color: var(--muted);
  font-size: 1.15rem;
  max-width: 46ch;
  margin-bottom: 2rem;
}

.hero-cta { display: flex; flex-wrap: wrap; align-items: center; gap: 1rem; }
.hero-note { font-size: 0.9rem; color: var(--muted); margin: 0; }

/* App icon panel */
.hero-icon {
  justify-self: center;
  position: relative;
}

.app-icon {
  width: clamp(200px, 28vw, 300px);
  aspect-ratio: 1;
  border-radius: 24%;
  background:
    radial-gradient(120% 120% at 20% 15%, #123B18 0%, var(--forest) 60%);
  box-shadow: var(--shadow-lg), inset 0 1px 0 rgba(255,255,255,0.06);
  display: grid;
  place-items: center;
  padding: 12%;
}
.app-icon svg { width: 100%; height: auto; }

/* gentle idle sway for the iguana */
.iguana-idle { animation: sway 6s ease-in-out infinite; transform-origin: 50% 90%; }
@keyframes sway {
  0%, 100% { transform: rotate(0deg); }
  50%      { transform: rotate(-2.5deg); }
}

.leaf-accent {
  position: absolute;
  color: var(--green);
  opacity: 0.35;
  width: 44px;
}
.leaf-1 { top: -18px; right: -10px; transform: rotate(30deg); }
.leaf-2 { bottom: -14px; left: -22px; transform: rotate(-115deg); width: 36px; }

/* ---------- CEFR trail (signature element) ---------- */
.cefr-trail {
  margin-top: clamp(3rem, 7vw, 4.5rem);
}
.cefr-title {
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--muted);
  text-align: center;
  margin-bottom: 1rem;
}
.cefr-steps {
  display: grid;
  grid-template-columns: repeat(6, 1fr);
  gap: 0.6rem;
  list-style: none;
  margin: 0;
  padding: 0;
}
.cefr-steps li {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  text-align: center;
  padding: 0.8rem 0.3rem;
  box-shadow: var(--shadow-sm);
  transition: transform 250ms var(--ease-spring), box-shadow 250ms var(--ease-out),
              border-color 250ms var(--ease-out);
}
.cefr-steps li:hover {
  transform: translateY(-4px);
  border-color: var(--green);
  box-shadow: var(--shadow-md);
}
.cefr-steps .lvl {
  display: block;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 1.3rem;
  color: var(--green-dark);
}
@media (prefers-color-scheme: dark) {
  .cefr-steps .lvl { color: #4ADE80; }
}
.cefr-steps .count {
  display: block;
  font-size: 0.75rem;
  color: var(--muted);
}
@media (max-width: 560px) {
  .cefr-steps { grid-template-columns: repeat(3, 1fr); }
}

/* ---------- Features ---------- */
.features { background: var(--tint); }

.feature-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: 1.1rem;
}

.feature-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.5rem 1.4rem;
  box-shadow: var(--shadow-sm);
  transition: transform 250ms var(--ease-spring), box-shadow 250ms var(--ease-out);
}
.feature-card:hover {
  transform: translateY(-5px);
  box-shadow: var(--shadow-md);
}
.feature-card h3 { margin-top: 0.9rem; margin-bottom: 0.35rem; }
.feature-card p { color: var(--muted); font-size: 0.97rem; margin: 0; }

.feature-icon {
  width: 44px;
  height: 44px;
  border-radius: 12px;
  background: var(--chip);
  color: var(--green-dark);
  display: grid;
  place-items: center;
}
@media (prefers-color-scheme: dark) {
  .feature-icon { color: var(--green-pale); }
}
.feature-icon svg { width: 24px; height: 24px; }

/* ---------- How it works ---------- */
.steps {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1.2rem;
  counter-reset: step;
}
@media (max-width: 760px) {
  .steps { grid-template-columns: 1fr; }
}

.step {
  position: relative;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.6rem 1.4rem 1.4rem;
  box-shadow: var(--shadow-sm);
}
.step::before {
  counter-increment: step;
  content: counter(step);
  display: inline-grid;
  place-items: center;
  width: 38px;
  height: 38px;
  border-radius: 50%;
  background: var(--green);
  color: var(--forest); /* AA contrast on brand green */
  font-weight: 700;
  font-size: 1.05rem;
  margin-bottom: 1rem;
}
.step h3 { margin-bottom: 0.35rem; }
.step p { color: var(--muted); font-size: 0.97rem; margin: 0; }

/* ---------- Screenshots ---------- */
.shots { background: var(--tint); }

.shot-strip {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 1.1rem;
}
@media (max-width: 900px) { .shot-strip { grid-template-columns: repeat(2, 1fr); } }
@media (max-width: 480px) { .shot-strip { grid-template-columns: 1fr; } }

.phone {
  aspect-ratio: 9 / 19;
  border-radius: 26px;
  border: 1.5px solid var(--border);
  background: var(--surface);
  box-shadow: var(--shadow-sm);
  padding: 10px;
  transition: transform 250ms var(--ease-spring), box-shadow 250ms var(--ease-out);
}
.phone:hover { transform: translateY(-5px); box-shadow: var(--shadow-md); }

.phone-screen {
  height: 100%;
  border-radius: 18px;
  border: 1.5px dashed var(--border);
  background:
    linear-gradient(160deg, var(--tint) 0%, var(--surface) 70%);
  display: grid;
  place-items: center;
  text-align: center;
  color: var(--muted);
  font-size: 0.85rem;
  padding: 1rem;
}
.phone-screen svg { width: 40px; height: 40px; margin-inline: auto; margin-bottom: 0.5rem; opacity: 0.6; }

/* ---------- FAQ ---------- */
.faq-list {
  max-width: 46rem;
  display: grid;
  gap: 0.8rem;
}

.faq-item {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  box-shadow: var(--shadow-sm);
  overflow: hidden;
}
.faq-item summary {
  list-style: none;
  cursor: pointer;
  padding: 1.1rem 1.3rem;
  font-weight: 650;
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 1rem;
}
.faq-item summary::-webkit-details-marker { display: none; }
.faq-item summary::after {
  content: "";
  flex-shrink: 0;
  width: 10px;
  height: 10px;
  border-right: 2px solid var(--green);
  border-bottom: 2px solid var(--green);
  transform: rotate(45deg);
  transition: transform 250ms var(--ease-out);
}
.faq-item[open] summary::after { transform: rotate(-135deg); }
.faq-item .answer {
  padding: 0 1.3rem 1.2rem;
  color: var(--muted);
}
.faq-item .answer p:last-child { margin-bottom: 0; }

/* ---------- Bottom CTA ---------- */
.cta-band {
  background: var(--forest);
  color: var(--green-pale);
  border-radius: var(--radius-lg);
  padding: clamp(2.2rem, 6vw, 3.5rem);
  display: grid;
  grid-template-columns: 1fr auto;
  align-items: center;
  gap: 1.5rem;
}
@media (max-width: 720px) { .cta-band { grid-template-columns: 1fr; } }
.cta-band h2 { color: #ffffff; margin-bottom: 0.3em; }
.cta-band p { color: var(--green-pale); margin: 0; opacity: 0.9; }

/* ---------- Footer ---------- */
.site-footer {
  border-top: 1px solid var(--border);
  padding-block: 2.2rem;
  margin-top: clamp(3rem, 7vw, 5rem);
}
.footer-row {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  color: var(--muted);
  font-size: 0.92rem;
}
.footer-row nav { display: flex; flex-wrap: wrap; gap: 1.2rem; }
.footer-brand { display: inline-flex; align-items: center; gap: 0.5rem; font-weight: 600; color: var(--text); }
.footer-brand .brand-mark { width: 28px; height: 28px; border-radius: 8px; }
.footer-brand .brand-mark svg { width: 20px; height: 20px; }

/* ---------- Scroll reveal ---------- */
.reveal {
  opacity: 0;
  transform: translateY(26px);
  transition: opacity 550ms ease, transform 550ms var(--ease-out);
}
.reveal.visible { opacity: 1; transform: none; }
.reveal-d1 { transition-delay: 80ms; }
.reveal-d2 { transition-delay: 160ms; }
.reveal-d3 { transition-delay: 240ms; }

/* If JS never runs (e.g. blocked), content must still be visible */
.no-js .reveal { opacity: 1; transform: none; }

/* ============================================================
   Privacy policy page
   ============================================================ */
.policy-layout {
  display: grid;
  grid-template-columns: 240px minmax(0, 1fr);
  gap: clamp(2rem, 5vw, 4rem);
  align-items: start;
  padding-block: clamp(2.5rem, 6vw, 4rem);
}
@media (max-width: 880px) {
  .policy-layout { grid-template-columns: minmax(0, 1fr); }
}

.toc {
  position: sticky;
  top: 88px;
  font-size: 0.9rem;
}
@media (max-width: 880px) {
  .toc { position: static; }
}
.toc-title {
  font-weight: 700;
  font-size: 0.8rem;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--muted);
  margin-bottom: 0.7rem;
}
.toc ol {
  list-style: none;
  margin: 0;
  padding: 0;
  border-left: 2px solid var(--border);
}
.toc li a {
  display: block;
  padding: 0.32rem 0 0.32rem 0.9rem;
  color: var(--muted);
  text-decoration: none;
  border-left: 2px solid transparent;
  margin-left: -2px;
  transition: color 150ms var(--ease-out), border-color 150ms var(--ease-out);
}
.toc li a:hover { color: var(--green-dark); border-left-color: var(--green); }
@media (prefers-color-scheme: dark) {
  .toc li a:hover { color: #4ADE80; }
}

.policy {
  max-width: 70ch;
}
.policy .eyebrow { margin-bottom: 0.3rem; }
.policy h1 { margin-bottom: 0.2em; }
.policy .effective {
  color: var(--muted);
  font-size: 0.95rem;
  margin-bottom: 2.2rem;
}
.policy h2 {
  font-size: 1.45rem;
  margin-top: 2.4em;
  scroll-margin-top: 96px;
}
.policy h2:first-of-type { margin-top: 1.4em; }
.policy ul { padding-left: 1.3rem; }
.policy li { margin-bottom: 0.55em; }
.policy li::marker { color: var(--green); }
.policy code {
  font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  font-size: 0.88em;
  background: var(--chip);
  color: var(--green-dark);
  padding: 0.12em 0.4em;
  border-radius: 6px;
  overflow-wrap: anywhere;
}
@media (prefers-color-scheme: dark) {
  .policy code { color: var(--green-pale); }
}

.policy .summary-card {
  background: var(--tint);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.3rem 1.4rem;
  margin: 1.5rem 0 0;
}
.policy .summary-card p { margin: 0; }

.anchor-link {
  margin-left: 0.35em;
  font-family: var(--font-body);
  font-weight: 400;
  font-size: 0.8em;
  color: var(--border);
  text-decoration: none;
  opacity: 0;
  transition: opacity 150ms var(--ease-out);
}
.policy h2:hover .anchor-link,
.anchor-link:focus-visible { opacity: 1; color: var(--green); }

.back-link {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  font-size: 0.95rem;
  margin-bottom: 1.6rem;
  text-decoration: none;
  font-weight: 550;
}

/* ---------- Reduced motion ---------- */
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }
  .reveal { opacity: 1; transform: none; }
}