:root {
  --ink: #0B192C;
  --ink-soft: #3A4A63;
  --accent: #D97706;
  --accent-text: #B45309;
  --bg: #FAF8F4;
  --surface: #FFFFFF;
  --line: #E6E1D8;
  --radius: 14px;
  --max: 68rem;
  --shadow: 0 4px 20px -2px rgba(11, 25, 44, 0.05);
  --shadow-hover: 0 10px 28px -4px rgba(11, 25, 44, 0.12);
  --font: system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue", Arial,
    "Nirmala UI", "Tamil Sangam MN", "Noto Sans Tamil", sans-serif;
}

/* System Dark Mode */
@media (prefers-color-scheme: dark) {
  :root {
    --ink: #F8FAFC;
    --ink-soft: #94A3B8;
    --accent: #F59E0B;
    --accent-text: #FBBF24;
    --bg: #0B192C;
    --surface: #112239;
    --line: #1E3452;
    --shadow: 0 4px 20px -2px rgba(0, 0, 0, 0.35);
    --shadow-hover: 0 10px 28px -4px rgba(0, 0, 0, 0.55);
  }
}

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

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

body {
  margin: 0;
  font-family: var(--font);
  font-size: 1.0625rem;
  line-height: 1.65;
  color: var(--ink);
  background: var(--bg);
  transition: background-color 0.2s ease, color 0.2s ease;
}

img { max-width: 100%; height: auto; display: block; }

a { color: var(--accent-text); text-underline-offset: 0.18em; }
a:hover { color: var(--ink); }
a:focus-visible, .button:focus-visible, summary:focus-visible {
  outline: 3px solid var(--accent);
  outline-offset: 3px;
  border-radius: 4px;
}

h1, h2, h3 { line-height: 1.2; letter-spacing: -0.015em; margin: 0 0 0.6em; }
h1 { font-size: clamp(2rem, 4.5vw, 3rem); font-weight: 800; }
h2 { font-size: clamp(1.5rem, 3vw, 2rem); font-weight: 750; }
h3, .h3 { font-size: 1.2rem; font-weight: 700; }
p { margin: 0 0 1em; }

.container { max-width: var(--max); margin: 0 auto; padding: 0 1.25rem; }

.skip-link {
  position: absolute;
  left: -999px;
  top: 0.5rem;
  background: var(--ink);
  color: #fff;
  padding: 0.5rem 1rem;
  border-radius: 6px;
  z-index: 10;
}
.skip-link:focus { left: 0.5rem; }

/* Header */
.site-header {
  background: var(--surface);
  border-bottom: 1px solid var(--line);
  position: sticky;
  top: 0;
  z-index: 40;
}
.site-header .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem 1.5rem;
  padding-top: 0.85rem;
  padding-bottom: 0.85rem;
}
.brand { display: block; line-height: 0; }
.brand img { width: auto; height: 56px; }

.header-right {
  display: flex;
  align-items: center;
  gap: 1.25rem;
}

/* Navigation */
.site-nav ul {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.25rem 1.4rem;
  list-style: none;
  margin: 0;
  padding: 0;
}
.site-nav a {
  color: var(--ink-soft);
  font-weight: 600;
  font-size: 0.95rem;
  text-decoration: none;
  padding: 0.3rem 0;
  border-bottom: 2px solid transparent;
  transition: color 0.15s ease, border-color 0.15s ease;
}
.site-nav a:hover { color: var(--ink); }
.site-nav a[aria-current="page"] { color: var(--ink); border-bottom-color: var(--accent); }

/* Responsive Mobile Navigation */
.nav-toggle {
  display: none;
}
@media (max-width: 54rem) {
  .site-nav.desktop-nav {
    display: none;
  }
  .nav-toggle {
    display: block;
    position: relative;
  }
  .nav-toggle summary {
    list-style: none;
    cursor: pointer;
    padding: 0.45rem 0.85rem;
    border: 1px solid var(--line);
    border-radius: 8px;
    font-weight: 700;
    font-size: 0.9rem;
    color: var(--ink);
    background: var(--surface);
    display: inline-flex;
    align-items: center;
    gap: 0.4rem;
    user-select: none;
  }
  .nav-toggle summary::-webkit-details-marker {
    display: none;
  }
  .nav-toggle[open] summary {
    background: var(--bg);
  }
  .nav-toggle .mobile-menu {
    position: absolute;
    right: 0;
    top: calc(100% + 0.5rem);
    background: var(--surface);
    border: 1px solid var(--line);
    border-radius: var(--radius);
    padding: 0.85rem 1.25rem;
    box-shadow: var(--shadow-hover);
    min-width: 14rem;
    z-index: 50;
  }
  .nav-toggle .mobile-menu ul {
    flex-direction: column;
    align-items: flex-start;
    gap: 0.65rem;
  }
  .nav-toggle .mobile-menu a {
    display: block;
    width: 100%;
    padding: 0.2rem 0;
  }
}

/* Sections */
main { display: block; }
.section { padding: 4.5rem 0; }
.section + .section { border-top: 1px solid var(--line); }
.section-alt { background: var(--surface); }
.eyebrow {
  display: block;
  font-size: 0.78rem;
  font-weight: 700;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--accent-text);
  margin-bottom: 0.8rem;
}
.lead { font-size: 1.2rem; color: var(--ink-soft); max-width: 42rem; }
.page-head { padding: 4rem 0 2.5rem; }
.page-head .lead { margin-bottom: 0; }
.page-head .lead + p { margin-top: 1.25rem; }
.page-head .badge { margin-bottom: 1rem; }

/* Hero */
.hero { padding: 5rem 0 4.5rem; }
.hero h1 { max-width: 46rem; }
.actions { display: flex; flex-wrap: wrap; gap: 0.75rem; margin-top: 1.75rem; }
.button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  padding: 0.75rem 1.4rem;
  border-radius: 999px;
  font-weight: 700;
  font-size: 0.98rem;
  text-decoration: none;
  border: 2px solid var(--ink);
  transition: transform 0.15s ease, background 0.15s ease, color 0.15s ease;
}
.button svg {
  width: 1.2rem;
  height: 1.2rem;
  fill: currentColor;
  flex-shrink: 0;
}
.button-primary { background: var(--ink); color: #fff; }
.button-primary:hover { background: #1C2E48; color: #fff; transform: translateY(-1px); }
.button-secondary { color: var(--ink); }
.button-secondary:hover { background: var(--ink); color: #fff; transform: translateY(-1px); }

/* Principle & Emblem */
.principle-layout {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 2rem;
}
.principle-mark {
  width: 96px;
  height: 96px;
  flex-shrink: 0;
  opacity: 0.92;
}
@media (max-width: 48rem) {
  .principle-layout { flex-direction: column; }
  .principle-mark { width: 72px; height: 72px; }
}

.principle blockquote { margin: 0; }
.principle .quote {
  font-size: clamp(1.6rem, 3.4vw, 2.4rem);
  font-weight: 800;
  line-height: 1.25;
  max-width: 48rem;
}
.principle .cite { font-weight: 600; color: var(--ink-soft); margin-top: 1rem; }
.tamil-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(18rem, 1fr));
  gap: 1.5rem;
  margin-top: 2.5rem;
}
.tamil-card {
  background: var(--bg);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 1.5rem;
  box-shadow: var(--shadow);
  transition: transform 0.2s ease, box-shadow 0.2s ease;
}
.tamil-card:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-hover);
}
.tamil { font-size: 1.15rem; font-weight: 700; margin-bottom: 0.4rem; }
.translit { font-style: italic; color: var(--ink-soft); margin-bottom: 0.6rem; }

/* Cards */
.grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(16.5rem, 1fr));
  gap: 1.25rem;
  margin-top: 2rem;
}
.card {
  display: flex;
  flex-direction: column;
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 1.6rem;
  box-shadow: var(--shadow);
  transition: transform 0.2s ease, box-shadow 0.2s ease, border-color 0.2s ease;
}
.card:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-hover);
  border-color: var(--accent);
}
.section-alt .card { background: var(--bg); }
.card p { color: var(--ink-soft); }
.card .more { margin-top: auto; font-weight: 700; }
.card ul { margin: 0 0 1em; padding-left: 1.1rem; color: var(--ink-soft); }
.card li + li { margin-top: 0.3rem; }
.badge {
  display: inline-block;
  align-self: flex-start;
  font-size: 0.8rem;
  font-weight: 700;
  letter-spacing: 0.02em;
  padding: 0.2rem 0.65rem;
  border-radius: 999px;
  border: 1px solid var(--line);
  color: var(--ink-soft);
  margin-bottom: 0.9rem;
}
.badge-live { border-color: var(--accent); color: var(--accent-text); }

/* Product Showcase Mockup Cards */
.preview-card {
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 1.5rem;
  margin-top: 1.5rem;
  box-shadow: var(--shadow);
}
.word-tiles {
  display: flex;
  gap: 0.5rem;
  margin: 1rem 0;
  flex-wrap: wrap;
}
.word-tile {
  width: 3.2rem;
  height: 3.2rem;
  border-radius: 10px;
  border: 2px solid var(--line);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.4rem;
  font-weight: 800;
  background: var(--bg);
  color: var(--ink);
}
.word-tile.tile-correct {
  background: #10B981;
  border-color: #059669;
  color: #fff;
}
.word-tile.tile-present {
  background: #F59E0B;
  border-color: #D97706;
  color: #fff;
}

/* Feature Lists */
.feature-list {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(16rem, 1fr));
  gap: 1.25rem 2rem;
  list-style: none;
  padding: 0;
  margin: 2rem 0 0;
}
.feature-list li { border-top: 2px solid var(--accent); padding-top: 0.9rem; }
.feature-list strong { display: block; margin-bottom: 0.25rem; }
.feature-list span { color: var(--ink-soft); }
.note { font-size: 0.9rem; color: var(--ink-soft); }
.feature-list + .note { margin-top: 2.5rem; }
.actions + .note { margin: 1.25rem 0 0; }

code {
  font-family: ui-monospace, "Cascadia Code", Consolas, monospace;
  font-size: 0.88em;
  background: var(--bg);
  border: 1px solid var(--line);
  border-radius: 6px;
  padding: 0.1em 0.4em;
  overflow-wrap: anywhere;
}

/* Contact Zoho Form Responsive Frame */
.form-frame {
  width: 100%;
  height: 1000px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--surface);
}

/* Footer */
.site-footer {
  background: #0B192C;
  color: #C9D2E0;
  padding: 3rem 0;
  font-size: 0.92rem;
  border-top: 1px solid rgba(255, 255, 255, 0.08);
}
.site-footer .container {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 1.5rem;
}
.footer-left {
  display: flex;
  align-items: center;
  gap: 1rem;
}
.footer-mark {
  width: 36px;
  height: 36px;
  filter: brightness(0) invert(1);
  opacity: 0.9;
}
.site-footer a { color: #fff; text-decoration: none; }
.site-footer a:hover { text-decoration: underline; }
.site-footer ul { display: flex; flex-wrap: wrap; gap: 0.5rem 1.4rem; list-style: none; margin: 0; padding: 0; }
.site-footer p { margin: 0; }

/* Dark Mode Component Overrides */
@media (prefers-color-scheme: dark) {
  .button-primary {
    background: var(--accent);
    color: #0B192C;
    border-color: var(--accent);
  }
  .button-primary:hover {
    background: #FBBF24;
    border-color: #FBBF24;
    color: #0B192C;
  }
  .button-secondary {
    color: var(--ink);
    border-color: var(--line);
  }
  .button-secondary:hover {
    background: var(--surface);
    color: var(--accent-text);
    border-color: var(--accent);
  }
  .section-alt .card {
    background: #132640;
  }
  .principle-mark {
    filter: brightness(0) invert(1);
  }
}

@media (max-width: 52rem) {
  .hero { padding: 3.5rem 0 3.25rem; }
  .section { padding: 3.25rem 0; }
  .site-footer .container { flex-direction: column; align-items: flex-start; }
}