:root {
  --bg1: #0d1526;
  --bg2: #111b33;
  --dot: rgba(255,255,255,0.08);
  --ink: #f3f6ff;
  --ink-strong: #ffffff;
  --muted: #a9b8d7;
  --brand: #95baff;
  --brand-strong: #6ea1ff;
  --accent: #46e0a1;
  --card: rgba(255,255,255,0.08);
  --stroke: rgba(255,255,255,0.16);
  --radius: 22px;
  --shadow: 0 14px 34px rgba(0,0,0,0.38);
  --glow: 0 0 24px rgba(110,161,255,0.18);
  --glow-strong: 0 0 38px rgba(110,161,255,0.28);
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  color: var(--ink);
  font-family: Inter, system-ui, -apple-system, Segoe UI, Roboto, Arial, sans-serif;
  font-size: 1.15rem;
  line-height: 1.75;
  background:
    radial-gradient(circle at 1px 1px, var(--dot) 1.2px, transparent 1.2px) 0 0/26px 26px,
    linear-gradient(180deg, var(--bg1) 0%, var(--bg2) 100%);
  text-shadow: 0 0 0.01px rgba(0,0,0,0.08);
}

.brand-bar {
  height: 8px;
  background: linear-gradient(90deg, var(--brand) 0%, var(--brand-strong) 45%, var(--accent) 100%);
  box-shadow: 0 6px 22px rgba(110,161,255,0.25);
}

a {
  color: var(--brand);
  text-decoration: none;
}

a:hover {
  text-decoration: underline;
}

.wrap {
  max-width: 960px;
  margin: 0 auto;
  padding: 40px 20px 80px;
  position: relative;
}

.spotlight {
  position: absolute;
  inset: 0 auto auto 50%;
  width: 700px;
  height: 700px;
  transform: translateX(-50%);
  background: radial-gradient(closest-side, rgba(110,161,255,0.18), rgba(110,161,255,0.04) 60%, transparent 75%);
  filter: blur(2px);
  pointer-events: none;
}

.tile {
  margin-top: 26px;
  padding: 28px;
  border: 1px solid var(--stroke);
  background: var(--card);
  border-radius: var(--radius);
  box-shadow: var(--shadow), var(--glow);
  transform: translateY(0);
  transition: transform 0.15s ease, box-shadow 0.15s ease, background 0.15s ease, border-color 0.15s ease;
}

.tile:hover {
  transform: translateY(-2px);
  box-shadow: 0 18px 42px rgba(0,0,0,0.42), var(--glow-strong);
  background: rgba(255,255,255,0.09);
  border-color: rgba(255,255,255,0.2);
}

header.tile {
  padding: 36px 32px;
}

.title {
  display: flex;
  align-items: center;
  gap: 14px;
  margin: 0 0 10px;
  font-size: 2.4rem;
  font-weight: 800;
  background: linear-gradient(180deg, var(--brand) 0%, var(--brand-strong) 100%);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
  line-height: 1.3;
}

.title-icon {
  width: 32px;
  height: 32px;
  flex: 0 0 32px;
  filter: drop-shadow(0 0 8px rgba(110,161,255,0.35));
}

.sub {
  color: #d8e3ff;
  opacity: 0.95;
  margin: 0 0 8px;
  font-size: 1.1rem;
}

.topic {
  margin: 12px 0 0;
  font-weight: 700;
  color: #e8efff;
  font-size: 1.2rem;
}

h2 {
  font-size: 1.35rem;
  margin: 0 0 12px;
  color: #e7eeff;
  display: flex;
  align-items: center;
  gap: 10px;
}

h2 .h-icon {
  width: 20px;
  height: 20px;
  flex: 0 0 20px;
  opacity: 0.9;
}

p {
  margin: 12px 0;
}

ul {
  margin: 12px 0 0 24px;
  padding: 0;
}

li {
  margin: 8px 0;
}

.divider {
  height: 2px;
  margin: 20px 0 0 0;
  border: 0;
  background: linear-gradient(90deg, transparent, var(--brand-strong), transparent);
  opacity: 0.45;
}

.cta {
  display: flex;
  flex-wrap: wrap;
  gap: 14px;
  margin-top: 14px;
}

.btn {
  display: inline-block;
  padding: 16px 22px;
  font-weight: 700;
  font-size: 1.1rem;
  color: #0b1122;
  border-radius: 999px;
  border: 1px solid rgba(255,255,255,0.18);
  background: linear-gradient(180deg, var(--brand) 0%, var(--brand-strong) 100%);
  box-shadow: 0 8px 22px rgba(110,161,255,0.28), 0 0 18px rgba(110,161,255,0.18) inset;
  transition: transform 0.08s ease, filter 0.08s ease, box-shadow 0.08s ease;
}

.btn:hover {
  transform: translateY(-1px);
  filter: brightness(1.07);
  box-shadow: 0 10px 26px rgba(110,161,255,0.34), 0 0 22px rgba(110,161,255,0.22) inset;
}

.ref-list {
  list-style: none;
  padding: 0;
  margin: 12px 0 0 0;
}

.ref-list li {
  margin: 12px 0;
  padding: 12px 14px;
  border-radius: 14px;
  border: 1px solid rgba(255,255,255,0.12);
  background: rgba(255,255,255,0.06);
  font-size: 1.05rem;
}

.ref-list a {
  color: var(--brand-strong);
  font-weight: 600;
}

footer {
  margin-top: 32px;
  color: var(--muted);
  font-size: 1rem;
}

@media (max-width: 640px) {
  .title {
    font-size: 2rem;
  }

  .tile {
    padding: 22px;
  }

  .btn {
    width: 100%;
    text-align: center;
  }
}