:root {
  --bg: #f5f7fb;
  --bg-alt: #ebeff8;
  --panel: rgba(255, 255, 255, 0.7);
  --panel-border: rgba(26, 41, 68, 0.12);
  --text: #0f172a;
  --text-soft: #334155;
  --card-bg: rgba(255, 255, 255, 0.55);
  --card-inner: rgba(255, 255, 255, 0.92);
  --shadow: 0 10px 30px rgba(15, 23, 42, 0.14);
  --ring-a: #3b82f6;
  --ring-b: #14b8a6;
  --ring-c: #f97316;
}

body[data-theme="dark"] {
  --bg: #050711;
  --bg-alt: #091322;
  --panel: rgba(8, 14, 29, 0.76);
  --panel-border: rgba(139, 181, 255, 0.22);
  --text: #e2e8f0;
  --text-soft: #a5b4cc;
  --card-bg: rgba(13, 22, 43, 0.66);
  --card-inner: rgba(7, 13, 27, 0.9);
  --shadow: 0 14px 40px rgba(2, 6, 23, 0.55);
  --ring-a: #4f8bff;
  --ring-b: #3ddfb6;
  --ring-c: #ff8a3d;
}

* {
  box-sizing: border-box;
}

html,
body {
  margin: 0;
  min-height: 100%;
}

body {
  font-family: "Segoe UI", "SF Pro Text", "Helvetica Neue", Helvetica, Arial, sans-serif;
  color: var(--text);
  background:
    radial-gradient(900px 520px at -10% -20%, rgba(59, 130, 246, 0.2), transparent 62%),
    radial-gradient(750px 430px at 110% 0%, rgba(20, 184, 166, 0.2), transparent 56%),
    linear-gradient(160deg, var(--bg) 0%, var(--bg-alt) 100%);
  transition: background 250ms ease, color 250ms ease;
}

.page-shell {
  max-width: 1080px;
  margin: 0 auto;
  padding: 1rem 1rem 2rem;
}

.topbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0.45rem 0;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 0.45rem;
  text-decoration: none;
}

.brand__logo {
  display: block;
  height: 34px;
  width: auto;
  object-fit: contain;
}

.brand__text {
  font-size: 1.12rem;
  font-weight: 700;
  letter-spacing: 0.015em;
  color: var(--text);
}

.theme-toggle {
  border: 1px solid var(--panel-border);
  background: var(--panel);
  color: var(--text);
  border-radius: 999px;
  padding: 0.45rem 0.8rem;
  display: inline-flex;
  gap: 0.45rem;
  align-items: center;
  cursor: pointer;
  box-shadow: var(--shadow);
  backdrop-filter: blur(10px);
  transition: transform 170ms ease, border-color 170ms ease, background 170ms ease;
}

.theme-toggle:hover {
  transform: translateY(-1px);
  border-color: color-mix(in oklab, var(--ring-a), var(--panel-border) 35%);
}

.theme-toggle:focus-visible,
.resource-card:focus-visible {
  outline: 2px solid var(--ring-a);
  outline-offset: 3px;
}

.content {
  margin-top: 1.25rem;
  background: var(--panel);
  border: 1px solid var(--panel-border);
  border-radius: 24px;
  padding: 1.4rem;
  backdrop-filter: blur(12px);
}

.hero h1 {
  margin: 0;
  font-size: clamp(1.7rem, 3vw, 2.2rem);
  line-height: 1.15;
}

.hero p {
  margin: 0.65rem 0 0;
  color: var(--text-soft);
  max-width: 60ch;
}

.intro {
  margin-top: 1.35rem;
  padding: 1rem 1.05rem;
  border: 1px solid color-mix(in oklab, var(--panel-border), transparent 22%);
  border-radius: 16px;
  background: color-mix(in oklab, var(--card-inner), transparent 12%);
}

.intro h2 {
  margin: 0;
  font-size: clamp(2rem, 4.6vw, 3.2rem);
  line-height: 1.02;
  letter-spacing: 0.01em;
}

.intro__subtitle {
  margin: 0.4rem 0 0;
  font-size: clamp(1rem, 2vw, 1.28rem);
  color: color-mix(in oklab, var(--ring-a), var(--text-soft) 38%);
  font-weight: 600;
}

.intro__description {
  margin: 0.85rem 0 0;
  color: var(--text-soft);
  line-height: 1.6;
}

.resource-grid {
  margin-top: 1.35rem;
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(210px, 1fr));
  gap: 0.95rem;
}

.resource-card {
  position: relative;
  display: block;
  text-decoration: none;
  color: inherit;
  border-radius: 16px;
  background: linear-gradient(140deg, var(--ring-a), var(--ring-b), var(--ring-c));
  padding: 1px;
  box-shadow: var(--shadow);
  transition: transform 200ms ease, box-shadow 220ms ease;
}

.resource-card::before {
  content: "";
  position: absolute;
  inset: 0;
  border-radius: inherit;
  background: radial-gradient(circle at 10% 0, rgba(255, 255, 255, 0.28), transparent 42%);
  opacity: 0;
  transition: opacity 200ms ease;
  pointer-events: none;
}

.resource-card:hover {
  transform: translateY(-4px) scale(1.01);
  box-shadow: 0 18px 40px rgba(15, 23, 42, 0.22);
}

.resource-card:hover::before {
  opacity: 1;
}

.resource-card__inner {
  height: 100%;
  border-radius: 15px;
  background: var(--card-inner);
  border: 1px solid color-mix(in oklab, var(--panel-border), transparent 38%);
  padding: 0.95rem;
}

.resource-card__label {
  margin: 0;
  font-size: 1.03rem;
  font-weight: 650;
}

.resource-card__kind {
  margin: 0.4rem 0 0;
  font-size: 0.86rem;
  color: var(--text-soft);
  text-transform: uppercase;
  letter-spacing: 0.06em;
}

@media (max-width: 640px) {
  .page-shell {
    padding: 0.8rem 0.75rem 1.25rem;
  }

  .content {
    border-radius: 18px;
    padding: 1rem;
  }

  .theme-toggle__text {
    display: none;
  }
}