/* ===========================
   Lang4Kids website — shared styles
   =========================== */

:root {
  --color-primary:       #7C3AED;
  --color-primary-dark:  #6D28D9;
  --color-primary-light: #EDE9FE;
  --color-text:          #1F2937;
  --color-text-muted:    #6B7280;
  --color-bg:            #FFFFFF;
  --color-bg-alt:        #F9FAFB;
  --color-border:        #E5E7EB;
  --font:  -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Helvetica, Arial, sans-serif;
  --max-w: 860px;
  --radius: 8px;
  --shadow: 0 1px 3px rgba(0,0,0,0.12), 0 1px 2px rgba(0,0,0,0.06);
}

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

body {
  margin: 0;
  font-family: var(--font);
  font-size: 17px;
  line-height: 1.75;
  color: var(--color-text);
  background: var(--color-bg);
}

img { max-width: 100%; }

a {
  color: var(--color-primary-dark);
}
a:hover { color: var(--color-primary); }

/* ---- Skip link ---- */
.skip-link {
  position: absolute;
  top: -40px;
  left: 0;
  background: var(--color-primary);
  color: #fff;
  padding: 0.5rem 1rem;
  text-decoration: none;
  z-index: 999;
  border-radius: 0 0 4px 0;
}
.skip-link:focus { top: 0; }

/* ---- Layout ---- */
.container {
  max-width: var(--max-w);
  margin: 0 auto;
  padding: 0 1.5rem;
}

/* ---- Header ---- */
.site-header {
  background: var(--color-primary);
  color: #fff;
  padding: 1rem 0;
  position: sticky;
  top: 0;
  z-index: 100;
  box-shadow: var(--shadow);
}
.site-header .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 0.75rem;
}
.site-header a {
  color: #fff;
  text-decoration: none;
  font-weight: 600;
}
.site-header a:hover { text-decoration: underline; }
.site-logo { font-size: 1.2rem; font-weight: 800; letter-spacing: -0.01em; }
.site-nav  { display: flex; gap: 1.5rem; font-size: 0.9rem; }

/* ---- Hero ---- */
.hero {
  background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-primary-dark) 100%);
  color: #fff;
  padding: 5rem 1.5rem;
  text-align: center;
}
.hero h1 {
  font-size: clamp(2rem, 5vw, 3.25rem);
  font-weight: 800;
  line-height: 1.15;
  margin: 0 0 1rem;
  letter-spacing: -0.02em;
}
.hero p {
  font-size: clamp(1rem, 2.5vw, 1.2rem);
  max-width: 580px;
  margin: 0 auto 2rem;
  opacity: 0.93;
}

.btn-group {
  display: flex;
  gap: 1rem;
  justify-content: center;
  flex-wrap: wrap;
}
.btn {
  display: inline-block;
  padding: 0.75rem 1.75rem;
  border-radius: var(--radius);
  font-size: 1rem;
  font-weight: 600;
  text-decoration: none;
  transition: opacity 0.15s, transform 0.1s;
}
.btn:hover  { opacity: 0.88; transform: translateY(-1px); }
.btn-white  { background: #fff; color: var(--color-primary-dark); }
.btn-outline{ border: 2px solid #fff; color: #fff; background: transparent; }
.app-store-badge {
  display: inline-flex;
  align-items: center;
  transition: opacity 0.15s, transform 0.1s;
}
.app-store-badge:hover { opacity: 0.88; transform: translateY(-1px); }
.app-store-badge:focus-visible { outline: 2px solid #fff; outline-offset: 4px; }
.app-store-badge img { display: block; width: 150px; height: auto; }

/* ---- Feature cards ---- */
.cards {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 1.5rem;
  padding: 3rem 0;
}
.card {
  background: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: 1.75rem;
  box-shadow: var(--shadow);
  text-align: center;
}
.card-icon { font-size: 2.25rem; margin-bottom: 0.75rem; }
.card h3   { margin: 0 0 0.5rem; color: var(--color-primary-dark); font-size: 1.05rem; }
.card p    { margin: 0; font-size: 0.9rem; color: var(--color-text-muted); }
.card a    { display: inline-block; margin-top: 0.75rem; font-size: 0.9rem; font-weight: 600; }

/* ---- Page main content ---- */
main { padding: 3rem 1.5rem; }

.page-header {
  border-bottom: 2px solid var(--color-primary-light);
  padding-bottom: 1.5rem;
  margin-bottom: 2.5rem;
}
.page-header h1 {
  font-size: clamp(1.75rem, 4vw, 2.25rem);
  color: var(--color-primary-dark);
  margin: 0 0 0.35rem;
}
.page-header .meta {
  font-size: 0.875rem;
  color: var(--color-text-muted);
}

h2 {
  font-size: 1.25rem;
  color: var(--color-primary-dark);
  margin: 2.5rem 0 0.75rem;
  padding-bottom: 0.35rem;
  border-bottom: 1px solid var(--color-border);
}
h3 { font-size: 1.05rem; margin: 1.5rem 0 0.5rem; }

/* ---- Callout box ---- */
.callout {
  background: var(--color-primary-light);
  border-left: 4px solid var(--color-primary);
  border-radius: 0 var(--radius) var(--radius) 0;
  padding: 1rem 1.25rem;
  margin: 1.5rem 0;
}
.callout strong { color: var(--color-primary-dark); }

/* ---- Numbered steps ---- */
ol.steps { padding-left: 1.4rem; }
ol.steps li { margin-bottom: 0.4rem; }

/* ---- Footer ---- */
.site-footer {
  background: var(--color-bg-alt);
  border-top: 1px solid var(--color-border);
  padding: 2rem 1.5rem;
  text-align: center;
  font-size: 0.875rem;
  color: var(--color-text-muted);
}
.site-footer a   { color: var(--color-text-muted); }
.site-footer nav {
  margin-top: 0.75rem;
  display: flex;
  justify-content: center;
  gap: 1.5rem;
  flex-wrap: wrap;
}

/* ---- 404 page ---- */
.not-found {
  text-align: center;
  padding: 6rem 1.5rem;
}
.not-found .big { font-size: 5rem; font-weight: 900; color: var(--color-primary-light); line-height: 1; }
.not-found h1   { color: var(--color-primary-dark); margin-top: 0.5rem; }

/* ---- Responsive ---- */
@media (max-width: 600px) {
  .site-nav { gap: 1rem; font-size: 0.85rem; }
  main { padding: 2rem 1rem; }
  .hero { padding: 3rem 1rem; }
  .cards { grid-template-columns: 1fr; }
}