/*
  AI Online Classroom — site styles
  Author: Generated for aionlineclassroom.com
  Notes: No external dependencies. Responsive, accessible, theme-ready.
*/

:root {
  --bg: #0b1220;
  --bg-elev: rgba(255,255,255,0.06);
  --bg-elev-2: rgba(255,255,255,0.10);
  --text: rgba(255,255,255,0.92);
  --muted: rgba(255,255,255,0.70);
  --faint: rgba(255,255,255,0.55);
  --border: rgba(255,255,255,0.14);
  --shadow: 0 18px 55px rgba(0,0,0,0.35);
  --shadow-soft: 0 12px 30px rgba(0,0,0,0.25);

  --brand-1: #7c3aed; /* violet */
  --brand-2: #22c55e; /* green */
  --brand-3: #06b6d4; /* cyan */

  --link: #93c5fd;
  --danger: #fb7185;
  --warning: #fbbf24;
  --ok: #34d399;

  --radius-xl: 28px;
  --radius-lg: 18px;
  --radius-md: 14px;
  --radius-sm: 12px;
  --radius-xs: 10px;

  --container: 1120px;
  --gutter: 22px;

  --h1: clamp(2.1rem, 1.2rem + 2.6vw, 3.2rem);
  --h2: clamp(1.55rem, 1.1rem + 1.6vw, 2.15rem);
  --h3: clamp(1.15rem, 1.0rem + 0.6vw, 1.35rem);
  --p: 1.06rem;

  --focus: 0 0 0 3px rgba(34,197,94,0.35);
}

/* Optional light theme (toggle) */
html[data-theme="light"] {
  --bg: #f7f7fb;
  --bg-elev: rgba(10,17,32,0.05);
  --bg-elev-2: rgba(10,17,32,0.08);
  --text: rgba(10,17,32,0.92);
  --muted: rgba(10,17,32,0.72);
  --faint: rgba(10,17,32,0.60);
  --border: rgba(10,17,32,0.12);
  --shadow: 0 18px 55px rgba(10,17,32,0.18);
  --shadow-soft: 0 12px 30px rgba(10,17,32,0.14);
  --link: #2563eb;
}

* { box-sizing: border-box; }

html, body {
  margin: 0;
  padding: 0;
  background: var(--bg);
  color: var(--text);
  font-family: ui-sans-serif, system-ui, -apple-system, Segoe UI, Roboto, Helvetica, Arial, "Apple Color Emoji", "Segoe UI Emoji";
  line-height: 1.55;
  scroll-behavior: smooth;
}

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

a {
  color: var(--link);
  text-decoration: none;
}
a:hover { text-decoration: underline; }

::selection { background: rgba(124,58,237,0.35); }

/* Accessibility */
.skip-link {
  position: absolute;
  left: -999px;
  top: 10px;
  padding: 10px 14px;
  background: #111827;
  border: 1px solid var(--border);
  border-radius: 10px;
  z-index: 9999;
}
.skip-link:focus { left: 10px; outline: none; box-shadow: var(--focus); }

.container {
  width: 100%;
  max-width: var(--container);
  margin: 0 auto;
  padding: 0 var(--gutter);
}

/* Decorative background */
.page-bg {
  position: fixed;
  inset: 0;
  z-index: -1;
  overflow: hidden;
  pointer-events: none;
}
.page-bg::before,
.page-bg::after {
  content: "";
  position: absolute;
  width: 1100px;
  height: 1100px;
  border-radius: 50%;
  filter: blur(40px);
  opacity: 0.45;
  transform: translate3d(0,0,0);
}
.page-bg::before {
  top: -520px;
  left: -420px;
  background: radial-gradient(circle at 35% 40%, rgba(124,58,237,0.95), rgba(6,182,212,0.35), transparent 65%);
}
.page-bg::after {
  bottom: -560px;
  right: -480px;
  background: radial-gradient(circle at 45% 45%, rgba(34,197,94,0.85), rgba(124,58,237,0.30), transparent 64%);
}

/* Top bar */
.topbar {
  font-size: 0.95rem;
  color: var(--muted);
  padding: 10px 0;
}
.topbar .topbar-row {
  display: flex;
  gap: 14px;
  justify-content: space-between;
  align-items: center;
}
.topbar a { color: var(--muted); text-decoration: none; }
.topbar a:hover { color: var(--text); text-decoration: underline; }

/* Header / Nav */
.site-header {
  position: sticky;
  top: 0;
  z-index: 2000;
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
  background: linear-gradient(to bottom, rgba(11,18,32,0.80), rgba(11,18,32,0.55));
  border-bottom: 1px solid var(--border);
}
html[data-theme="light"] .site-header {
  background: linear-gradient(to bottom, rgba(247,247,251,0.80), rgba(247,247,251,0.55));
}

.nav {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 14px 0;
  gap: 14px;
}

.brand {
  display: flex;
  align-items: center;
  gap: 12px;
}
.brand-mark {
  width: 38px;
  height: 38px;
  display: grid;
  place-items: center;
  border-radius: 12px;
  background: linear-gradient(135deg, rgba(124,58,237,0.95), rgba(6,182,212,0.65));
  box-shadow: 0 10px 30px rgba(124,58,237,0.22);
}
.brand-title {
  display: flex;
  flex-direction: column;
  line-height: 1.05;
}
.brand-title strong { font-weight: 750; letter-spacing: 0.2px; }
.brand-title span { color: var(--muted); font-size: 0.92rem; }

.nav-links {
  display: flex;
  gap: 18px;
  align-items: center;
}
.nav-links a {
  color: var(--muted);
  padding: 10px 10px;
  border-radius: 12px;
  text-decoration: none;
}
.nav-links a:hover {
  color: var(--text);
  background: var(--bg-elev);
}
.nav-links a[aria-current="page"] {
  color: var(--text);
  background: var(--bg-elev-2);
  border: 1px solid var(--border);
}

.nav-actions {
  display: flex;
  gap: 10px;
  align-items: center;
}

.icon-btn {
  border: 1px solid var(--border);
  background: var(--bg-elev);
  color: var(--text);
  border-radius: 12px;
  padding: 10px 12px;
  cursor: pointer;
  transition: transform 160ms ease, background 160ms ease;
}
.icon-btn:hover { background: var(--bg-elev-2); transform: translateY(-1px); }
.icon-btn:focus { outline: none; box-shadow: var(--focus); }

.nav-toggle {
  display: none;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  padding: 12px 16px;
  border-radius: 14px;
  font-weight: 650;
  border: 1px solid var(--border);
  cursor: pointer;
  transition: transform 160ms ease, background 160ms ease, border-color 160ms ease;
  text-decoration: none;
}
.btn:hover { transform: translateY(-1px); text-decoration: none; }
.btn:focus { outline: none; box-shadow: var(--focus); }

.btn-primary {
  color: #0b1220;
  border-color: transparent;
  background: linear-gradient(135deg, rgba(34,197,94,1), rgba(6,182,212,1));
  box-shadow: 0 14px 40px rgba(6,182,212,0.20);
}
html[data-theme="light"] .btn-primary { color: #071019; }
.btn-primary:hover { filter: brightness(1.03); }

.btn-secondary {
  color: var(--text);
  background: var(--bg-elev);
}
.btn-secondary:hover { background: var(--bg-elev-2); }

.btn-ghost {
  color: var(--text);
  background: transparent;
}
.btn-ghost:hover { background: var(--bg-elev); }

.badge {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 8px 12px;
  border-radius: 999px;
  background: rgba(124,58,237,0.16);
  border: 1px solid rgba(124,58,237,0.30);
  color: var(--text);
  font-weight: 600;
  font-size: 0.95rem;
}

/* Hero */
.hero {
  padding: 44px 0 26px;
}
.hero-grid {
  display: grid;
  grid-template-columns: 1.12fr 0.88fr;
  gap: 26px;
  align-items: start;
}
.hero h1 {
  font-size: var(--h1);
  line-height: 1.08;
  margin: 14px 0 14px;
  letter-spacing: -0.02em;
}
.hero p {
  font-size: 1.12rem;
  color: var(--muted);
  margin: 0 0 18px;
}
.hero .cta-row {
  display: flex;
  gap: 12px;
  flex-wrap: wrap;
  margin-top: 18px;
}

.hero-card {
  border: 1px solid var(--border);
  background: linear-gradient(180deg, var(--bg-elev), rgba(255,255,255,0.02));
  border-radius: var(--radius-xl);
  box-shadow: var(--shadow);
  padding: 18px;
  overflow: hidden;
  position: relative;
}
.hero-card::before {
  content: "";
  position: absolute;
  inset: -120px -120px auto auto;
  width: 280px;
  height: 280px;
  background: radial-gradient(circle at 30% 30%, rgba(6,182,212,0.55), transparent 60%);
  filter: blur(4px);
  opacity: 0.9;
}

.hero-card h2 {
  font-size: 1.1rem;
  margin: 0 0 12px;
  color: var(--text);
}
.hero-card ul {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 10px;
}
.hero-card li {
  display: flex;
  gap: 10px;
  align-items: start;
  color: var(--muted);
  padding: 10px 12px;
  border-radius: 14px;
  background: rgba(255,255,255,0.03);
  border: 1px solid rgba(255,255,255,0.06);
}
html[data-theme="light"] .hero-card li {
  background: rgba(10,17,32,0.03);
  border: 1px solid rgba(10,17,32,0.06);
}

.check {
  flex: 0 0 auto;
  width: 18px;
  height: 18px;
  margin-top: 2px;
  border-radius: 6px;
  background: rgba(34,197,94,0.22);
  border: 1px solid rgba(34,197,94,0.35);
  display: grid;
  place-items: center;
}

/* Sections */
.section {
  padding: 34px 0;
}
.section h2 {
  font-size: var(--h2);
  margin: 0 0 10px;
  letter-spacing: -0.015em;
}
.section p.lead {
  color: var(--muted);
  font-size: 1.08rem;
  margin: 0 0 18px;
}

.grid-3 {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 16px;
}
.grid-2 {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 16px;
}

.card {
  border: 1px solid var(--border);
  background: linear-gradient(180deg, var(--bg-elev), rgba(255,255,255,0.02));
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-soft);
  padding: 16px;
}
.card h3 {
  font-size: var(--h3);
  margin: 0 0 8px;
}
.card p { margin: 0; color: var(--muted); font-size: 1.02rem; }
.card .meta {
  margin-top: 10px;
  color: var(--faint);
  font-size: 0.98rem;
}

.kpi {
  display: grid;
  grid-template-columns: 1fr;
  gap: 8px;
  padding: 16px;
  border-radius: var(--radius-lg);
  border: 1px dashed rgba(34,197,94,0.35);
  background: rgba(34,197,94,0.10);
}

.kpi strong { font-size: 1.2rem; }
.kpi span { color: var(--muted); }

/* Wide content */
.prose {
  border: 1px solid var(--border);
  background: linear-gradient(180deg, rgba(255,255,255,0.04), rgba(255,255,255,0.02));
  border-radius: var(--radius-xl);
  padding: 20px;
}
html[data-theme="light"] .prose {
  background: linear-gradient(180deg, rgba(10,17,32,0.04), rgba(10,17,32,0.02));
}

.prose h2, .prose h3 { margin-top: 18px; }
.prose h2:first-child { margin-top: 0; }
.prose p { color: var(--muted); font-size: var(--p); }
.prose ul { color: var(--muted); }
.prose li { margin: 8px 0; }

.hr {
  height: 1px;
  background: var(--border);
  margin: 16px 0;
}

/* Testimonials / Cases */
.quote {
  border-left: 3px solid rgba(6,182,212,0.70);
  padding-left: 14px;
  margin: 0;
  color: var(--muted);
}
.quote footer {
  margin-top: 10px;
  color: var(--faint);
  font-size: 0.98rem;
}

.pill-row {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}
.pill {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 8px 12px;
  border-radius: 999px;
  border: 1px solid var(--border);
  background: var(--bg-elev);
  color: var(--muted);
  font-weight: 600;
  font-size: 0.95rem;
}

/* FAQ */
.faq {
  display: grid;
  gap: 12px;
}
.details {
  border: 1px solid var(--border);
  background: var(--bg-elev);
  border-radius: var(--radius-lg);
  padding: 14px;
}
.details summary {
  cursor: pointer;
  font-weight: 700;
  color: var(--text);
}
.details p { margin: 10px 0 0; color: var(--muted); }

/* Forms */
.form {
  display: grid;
  gap: 12px;
}
.field {
  display: grid;
  gap: 6px;
}
label {
  color: var(--muted);
  font-weight: 650;
}
input, textarea, select {
  width: 100%;
  padding: 12px 12px;
  border-radius: 14px;
  border: 1px solid var(--border);
  background: rgba(255,255,255,0.04);
  color: var(--text);
  outline: none;
}
html[data-theme="light"] input,
html[data-theme="light"] textarea,
html[data-theme="light"] select {
  background: rgba(10,17,32,0.04);
}

input:focus, textarea:focus, select:focus { box-shadow: var(--focus); border-color: rgba(34,197,94,0.45); }
textarea { min-height: 140px; resize: vertical; }
.help {
  color: var(--faint);
  font-size: 0.95rem;
}
.error {
  color: var(--danger);
  font-size: 0.95rem;
  font-weight: 650;
}
.success {
  border: 1px solid rgba(34,197,94,0.35);
  background: rgba(34,197,94,0.10);
  padding: 12px 14px;
  border-radius: 16px;
  color: var(--text);
}

/* Footer */
.site-footer {
  border-top: 1px solid var(--border);
  margin-top: 30px;
  padding: 30px 0 38px;
}
.footer-grid {
  display: grid;
  grid-template-columns: 1.4fr 0.6fr 0.6fr;
  gap: 16px;
}
.footer-grid a { color: var(--muted); }
.footer-grid a:hover { color: var(--text); }
.footer-note { color: var(--faint); font-size: 0.95rem; margin-top: 12px; }

/* Cookie banner */
.cookie {
  position: fixed;
  left: 14px;
  right: 14px;
  bottom: 14px;
  z-index: 4000;
  display: none;
}
.cookie .cookie-card {
  max-width: 980px;
  margin: 0 auto;
  border: 1px solid var(--border);
  background: rgba(11,18,32,0.86);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-radius: var(--radius-xl);
  box-shadow: var(--shadow);
  padding: 14px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 14px;
}
html[data-theme="light"] .cookie .cookie-card {
  background: rgba(247,247,251,0.90);
}
.cookie p {
  margin: 0;
  color: var(--muted);
}
.cookie .cookie-actions {
  display: flex;
  gap: 10px;
  flex-wrap: wrap;
}

/* Back to top */
.backtop {
  position: fixed;
  right: 14px;
  bottom: 86px;
  z-index: 3500;
  display: none;
}

/* Mobile */
@media (max-width: 980px) {
  .hero-grid { grid-template-columns: 1fr; }
  .grid-3 { grid-template-columns: 1fr; }
  .grid-2 { grid-template-columns: 1fr; }
  .footer-grid { grid-template-columns: 1fr; }

  .nav-links {
    display: none;
    position: absolute;
    top: 64px;
    left: var(--gutter);
    right: var(--gutter);
    padding: 12px;
    border-radius: 18px;
    border: 1px solid var(--border);
    background: rgba(11,18,32,0.92);
    box-shadow: var(--shadow);
    flex-direction: column;
    align-items: stretch;
    gap: 6px;
  }
  html[data-theme="light"] .nav-links { background: rgba(247,247,251,0.92); }

  .nav-links a { padding: 12px 12px; }
  .nav-toggle { display: inline-flex; }
  .nav.open .nav-links { display: flex; }
}

@media (prefers-reduced-motion: reduce) {
  html, body { scroll-behavior: auto; }
  .icon-btn, .btn { transition: none; }
}