/* aicomparison.co.uk — assets/style.css
   Dark, electric, tech-forward. Blue → violet → cyan identity.
   Mobile-first, dependency-free, tuned for Core Web Vitals.
   Ad slots reserve height to keep CLS near zero.
   Same class names as the linux101 build — templates are interchangeable. */

:root {
  --bg:        #0b0e16;
  --surface:   #141927;
  --surface-2: #1c2336;
  --border:    #283149;
  --text:      #e9edf6;
  --muted:     #8e98b3;
  --accent:    #38bdf8;   /* electric cyan-blue */
  --accent-2:  #8b5cf6;   /* violet */
  --good:      #34d399;
  --bad:       #fb7185;
  --radius:    14px;
  --maxw:      760px;
  --maxw-wide: 1080px;

  /* Brand gradients + shadows */
  --grad:      linear-gradient(135deg, #38bdf8 0%, #6366f1 50%, #a855f7 100%);
  --grad-soft: linear-gradient(135deg, rgba(56,189,248,.14), rgba(168,85,247,.14));
  --spectrum:  linear-gradient(90deg,#38bdf8,#6366f1,#a855f7,#ec4899,#38bdf8);
  --shadow:    0 6px 24px rgba(0,0,0,.35);
  --shadow-lg: 0 16px 44px rgba(0,0,0,.55);
}

* { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; }

body {
  margin: 0;
  color: var(--text);
  background:
    radial-gradient(900px 500px at 12% 0%, rgba(56,189,248,.08) 0%, transparent 60%),
    radial-gradient(800px 500px at 92% 4%, rgba(168,85,247,.1) 0%, transparent 55%),
    var(--bg);
  font: 17px/1.65 system-ui, -apple-system, Segoe UI, Roboto, Helvetica, Arial, sans-serif;
  -webkit-font-smoothing: antialiased;
}

.container { width: 100%; max-width: var(--maxw); margin: 0 auto; padding: 0 18px; }
.container.wide { max-width: var(--maxw-wide); }

a { color: var(--accent); text-decoration: none; font-weight: 600; }
a:hover { text-decoration: underline; }

h1, h2, h3 { line-height: 1.2; font-weight: 800; letter-spacing: -.01em; }
h1 { font-size: clamp(1.9rem, 5.5vw, 2.6rem); margin: .5em 0 .4em; }
h2 { font-size: clamp(1.4rem, 4vw, 1.85rem); margin: 1.7em 0 .6em; }
h3 { font-size: 1.18rem; margin: 1.3em 0 .4em; }

/* gradient accent bar under section headings */
h2::after {
  content: ""; display: block; width: 56px; height: 4px;
  margin-top: .35em; border-radius: 99px; background: var(--grad);
}
h2.bare::after { display: none; }

p, ul, ol { margin: 0 0 1em; }
img { max-width: 100%; height: auto; }

/* ---------- Header / nav ---------- */
.site-header {
  background: rgba(13,17,28,.85);
  backdrop-filter: saturate(160%) blur(12px);
  -webkit-backdrop-filter: saturate(160%) blur(12px);
  border-bottom: 1px solid var(--border);
  position: sticky; top: 0; z-index: 50;
}
.site-header::before {            /* spectrum strip */
  content: ""; display: block; height: 4px; background: var(--spectrum);
}
.nav-row {
  display: flex; align-items: center; gap: 16px;
  min-height: 60px; flex-wrap: wrap;
}
.logo {
  font-weight: 900; font-size: 1.2rem; white-space: nowrap;
  background: var(--grad); -webkit-background-clip: text; background-clip: text;
  -webkit-text-fill-color: transparent; color: var(--accent);
}
.logo:hover { text-decoration: none; filter: brightness(1.1); }
.site-header nav { display: flex; gap: 4px 16px; flex-wrap: wrap; }
.site-header nav a {
  color: var(--muted); font-size: .95rem; font-weight: 600; padding: 6px 2px;
  border-bottom: 2px solid transparent; transition: color .12s ease, border-color .12s ease;
}
.site-header nav a:hover { color: var(--accent); border-bottom-color: var(--accent); text-decoration: none; }

/* ---------- Layout helpers ---------- */
main { padding: 22px 0 56px; }
.meta-dates { color: var(--muted); font-size: .85rem; margin: -.2em 0 1.4em; font-weight: 500; }
.lead { font-size: 1.18rem; color: #b9c2d8; }

.grid { display: grid; gap: 18px; grid-template-columns: 1fr; }
@media (min-width: 620px) { .grid.cols-2 { grid-template-columns: 1fr 1fr; } }
@media (min-width: 860px) { .grid.cols-3 { grid-template-columns: repeat(3, 1fr); } }

/* ---------- Hero (homepage) ---------- */
.hero {
  position: relative; overflow: hidden;
  color: #fff; border-radius: 26px;
  padding: clamp(36px, 7vw, 64px) clamp(24px, 5vw, 48px);
  margin: 10px 0 18px;
  background: linear-gradient(120deg, #0ea5e9, #6366f1, #a855f7, #0ea5e9);
  background-size: 300% 300%;
  animation: heroShift 16s ease infinite;
  box-shadow: var(--shadow-lg);
}
.hero::after {
  content: ""; position: absolute; inset: 0;
  background: radial-gradient(60% 80% at 85% -10%, rgba(255,255,255,.28), transparent 60%);
  pointer-events: none;
}
.hero h1 { color: #fff; font-size: clamp(2.1rem, 6.5vw, 3.2rem); margin-top: 0; }
.hero .lead { color: rgba(255,255,255,.94); max-width: 44ch; }
.hero .btn { background: #fff; color: #4338ca; box-shadow: 0 8px 24px rgba(0,0,0,.22); }
.hero .btn:hover { transform: translateY(-2px); box-shadow: 0 12px 30px rgba(0,0,0,.3); }
.hero .btn.secondary {
  background: rgba(255,255,255,.14); color: #fff;
  border: 1.5px solid rgba(255,255,255,.6);
}
.hero .btn.secondary:hover { background: rgba(255,255,255,.24); }
@keyframes heroShift { 0%{background-position:0% 50%} 50%{background-position:100% 50%} 100%{background-position:0% 50%} }

/* ---------- Cards ---------- */
.card {
  position: relative; background: var(--surface);
  border: 1px solid var(--border); border-radius: var(--radius);
  padding: 20px; box-shadow: var(--shadow);
  transition: transform .16s ease, box-shadow .16s ease, border-color .16s ease;
}
.card:hover { transform: translateY(-4px); box-shadow: var(--shadow-lg); border-color: #3b4a73; }
.card h3 { margin-top: 0; }
.card h3 a { color: var(--text); }
.card h3 a:hover { color: var(--accent); }
.card .tagline { color: var(--muted); font-size: .96rem; }

.badge {
  display: inline-block; font-size: .72rem; font-weight: 800;
  text-transform: uppercase; letter-spacing: .05em;
  padding: 4px 10px; border-radius: 999px;
  background: rgba(139,92,246,.16); color: #c4b5fd; border: 1px solid rgba(139,92,246,.35);
}
.badge.cyan { background: rgba(56,189,248,.14); color: #7dd3fc; border-color: rgba(56,189,248,.35); }
.badge.free { background: rgba(52,211,153,.14); color: #6ee7b7; border-color: rgba(52,211,153,.35); }

/* ---------- Buttons ---------- */
.btn {
  display: inline-block; cursor: pointer;
  background: var(--grad); color: #fff;
  font-weight: 800; border: 0; border-radius: 12px;
  padding: 13px 22px; font-size: 1rem; margin: 4px 6px 4px 0;
  box-shadow: 0 8px 20px rgba(99,102,241,.35);
  transition: transform .15s ease, box-shadow .15s ease, filter .15s ease;
}
.btn:hover { transform: translateY(-2px); box-shadow: 0 12px 28px rgba(99,102,241,.5); text-decoration: none; filter: brightness(1.05); }
.btn.secondary {
  background: var(--surface-2); color: var(--text);
  border: 1.5px solid var(--border); box-shadow: none;
}
.btn.secondary:hover { border-color: var(--accent); color: var(--accent); box-shadow: var(--shadow); }

/* ---------- Pros / cons ---------- */
.proscons { display: grid; gap: 16px; grid-template-columns: 1fr; }
@media (min-width: 620px) { .proscons { grid-template-columns: 1fr 1fr; } }
.proscons ul { list-style: none; padding: 0; margin: 0; }
.proscons li { padding: 7px 0 7px 28px; position: relative; color: var(--text); }
.proscons .pros li::before { content: "✔"; color: var(--good); font-weight: 900; position: absolute; left: 0; }
.proscons .cons li::before { content: "✕"; color: var(--bad);  font-weight: 900; position: absolute; left: 0; }
.card.pros { border-color: #14532d; background: linear-gradient(180deg,#0c2b1d,#141927); }
.card.cons { border-color: #581c2e; background: linear-gradient(180deg,#2b0f18,#141927); }
.card.pros h3, .card.pros li, .card.pros p { color: var(--text); }
.card.cons h3, .card.cons li, .card.cons p { color: var(--text); }

/* ---------- Comparison & pricing tables ---------- */
.compare-table {
  width: 100%; border-collapse: collapse; font-size: .96rem;
  background: var(--surface); border-radius: var(--radius); overflow: hidden;
  box-shadow: var(--shadow);
}
.compare-table th, .compare-table td {
  text-align: left; padding: 12px 14px; border-bottom: 1px solid var(--border); vertical-align: top;
  color: var(--text);
}
.compare-table th[scope="row"] { color: var(--muted); font-weight: 700; white-space: nowrap; background: var(--surface-2); }
.compare-table thead th { font-size: 1.05rem; background: var(--surface-2); }
.compare-table tbody tr:hover td { background: var(--surface-2); }
.table-scroll { overflow-x: auto; -webkit-overflow-scrolling: touch; border-radius: var(--radius); }

/* pricing page extras */
.price-figure { font-size: 1.3rem; font-weight: 900; color: var(--accent); white-space: nowrap; }
.price-note   { font-size: .82rem; color: var(--muted); }
tr.highlight td { background: var(--grad-soft) !important; }

/* ---------- Quiz (choose.php) ---------- */
.quiz-step { display: none; }
.quiz-step.active { display: block; }
.quiz-options { display: grid; gap: 12px; grid-template-columns: 1fr; margin: 18px 0; }
@media (min-width: 560px) { .quiz-options { grid-template-columns: 1fr 1fr; } }
.quiz-option {
  background: var(--surface); border: 1.5px solid var(--border);
  border-radius: var(--radius); padding: 16px; cursor: pointer; font-weight: 600;
  color: var(--text); text-align: left;
  box-shadow: var(--shadow);
  transition: border-color .12s ease, background .12s ease, transform .12s ease, box-shadow .12s ease, color .12s ease;
}
.quiz-option:hover { border-color: var(--accent); transform: translateY(-2px); box-shadow: var(--shadow-lg); color: var(--accent); }
.quiz-option.selected { border-color: var(--accent-2); background: var(--grad-soft); color: #c4b5fd; }
.quiz-progress { height: 8px; background: var(--surface-2); border-radius: 999px; overflow: hidden; margin: 8px 0 22px; }
.quiz-progress > span { display: block; height: 100%; background: var(--grad); width: 0; transition: width .25s ease; }

/* ---------- Ads — reserve space to avoid layout shift (CLS) ---------- */
.ad-wrap { margin: 30px 0; text-align: center; min-height: 100px; }
.ad-wrap .adsbygoogle { display: block; }
.ad-label {
  display: block; font-size: .68rem; letter-spacing: .1em;
  text-transform: uppercase; color: var(--muted); margin-bottom: 4px;
}
.ad-placeholder {
  border: 2px dashed rgba(139,92,246,.4); border-radius: var(--radius);
  color: #c4b5fd; background: var(--grad-soft);
  padding: 36px 12px; margin: 30px 0; text-align: center;
  font-size: .85rem; font-weight: 700; min-height: 100px;
}

/* ---------- Footer ---------- */
.site-footer {
  border-top: 1px solid var(--border);
  color: var(--muted); font-size: .9rem;
  padding: 26px 0 44px; margin-top: 48px;
}
.site-footer::before { content: ""; display: block; height: 3px; background: var(--spectrum); margin-bottom: 24px; opacity: .8; }
.site-footer a { color: var(--muted); }
.site-footer a:hover { color: var(--accent); }

/* ---------- Code (for prompt examples in guides) ---------- */
code {
  font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  font-size: .88rem; background: var(--surface-2);
  border: 1px solid var(--border); border-radius: 6px;
  padding: 2px 7px; color: var(--accent);
}

/* ---------- Entrance + A11y / motion ---------- */
:focus-visible { outline: 3px solid var(--accent); outline-offset: 2px; }

@media (prefers-reduced-motion: no-preference) {
  .card { animation: rise .4s ease both; }
  @keyframes rise { from { opacity: 0; transform: translateY(10px); } to { opacity: 1; transform: none; } }
}
@media (prefers-reduced-motion: reduce) {
  * { animation: none !important; transition: none !important; }
}