:root {
  color-scheme: dark;
  --bg: #070814;
  --panel: rgba(12, 17, 38, .76);
  --text: #f7fbff;
  --muted: rgba(226, 238, 255, .68);
  --cyan: #37f8ff;
  --pink: #ff3df2;
  --amber: #ffe16b;
  --green: #7cff80;
}

* { box-sizing: border-box; }

html, body { min-height: 100%; }
body {
  margin: 0;
  font-family: ui-rounded, "SF Pro Rounded", "Hiragino Sans", "Hiragino Kaku Gothic ProN", system-ui, sans-serif;
  color: var(--text);
  background:
    radial-gradient(circle at 18% 10%, rgba(255, 61, 242, .22), transparent 30%),
    radial-gradient(circle at 78% 18%, rgba(55, 248, 255, .20), transparent 32%),
    radial-gradient(circle at 50% 80%, rgba(255, 225, 107, .12), transparent 35%),
    var(--bg);
}

body::before {
  content: "";
  position: fixed;
  inset: 0;
  pointer-events: none;
  background:
    linear-gradient(rgba(255,255,255,.035) 1px, transparent 1px),
    linear-gradient(90deg, rgba(255,255,255,.035) 1px, transparent 1px);
  background-size: 44px 44px;
  mask-image: radial-gradient(circle at center, black, transparent 78%);
}

.hero {
  width: min(1120px, calc(100% - 32px));
  margin: 0 auto;
  padding: clamp(56px, 10vw, 108px) 0 24px;
  text-align: center;
}

.eyebrow {
  margin: 0 0 10px;
  color: var(--cyan);
  font-size: 13px;
  font-weight: 900;
  letter-spacing: .28em;
  text-transform: uppercase;
}

h1 {
  margin: 0;
  font-size: clamp(48px, 11vw, 116px);
  line-height: .88;
  letter-spacing: -.08em;
  text-shadow: 0 0 40px rgba(55, 248, 255, .24), 0 0 70px rgba(255, 61, 242, .22);
}

.lead {
  width: min(680px, 100%);
  margin: 22px auto 0;
  color: var(--muted);
  font-size: clamp(15px, 2.2vw, 19px);
  line-height: 1.85;
}

.grid {
  position: relative;
  z-index: 1;
  width: 100%;
  margin: 0;
  display: grid;
  /* セクション見出しと左右の端を揃えるため、列を幅いっぱいに伸ばす。
     auto-fill にしているのは、カードが 1 枚のときに auto-fit だと空の列が潰れて
     1 枚が横幅いっぱいに間延びしてしまうため */
  grid-template-columns: repeat(auto-fill, minmax(min(300px, 100%), 1fr));
  gap: 18px;
}

.card {
  overflow: hidden;
  border: 1px solid rgba(255,255,255,.13);
  border-radius: 28px;
  background: linear-gradient(160deg, rgba(18, 26, 62, .82), rgba(6, 8, 22, .86));
  box-shadow: 0 22px 70px rgba(0,0,0,.35), inset 0 0 80px rgba(255,255,255,.025);
  transform: translateZ(0);
}

.card:hover {
  transform: translateY(-4px);
  box-shadow: 0 28px 90px rgba(0,0,0,.46), 0 0 34px rgba(55,248,255,.12);
}

.thumb {
  height: 190px;
  display: grid;
  place-items: center;
  background:
    radial-gradient(circle, rgba(255,255,255,.18), transparent 36%),
    linear-gradient(135deg, rgba(55,248,255,.3), rgba(255,61,242,.26));
}

.thumb span {
  display: grid;
  place-items: center;
  width: 138px;
  height: 138px;
  border-radius: 999px;
  color: #031019;
  background: linear-gradient(90deg, var(--cyan), var(--pink), var(--amber));
  font-weight: 1000;
  letter-spacing: .08em;
  box-shadow: 0 0 44px rgba(55,248,255,.5);
}

.tetrisThumb {
  background:
    linear-gradient(90deg, transparent 0 18%, rgba(255,255,255,.08) 18% 20%, transparent 20% 38%, rgba(255,255,255,.08) 38% 40%, transparent 40% 58%, rgba(255,255,255,.08) 58% 60%, transparent 60% 78%, rgba(255,255,255,.08) 78% 80%, transparent 80%),
    linear-gradient(0deg, transparent 0 18%, rgba(255,255,255,.08) 18% 20%, transparent 20% 38%, rgba(255,255,255,.08) 38% 40%, transparent 40% 58%, rgba(255,255,255,.08) 58% 60%, transparent 60% 78%, rgba(255,255,255,.08) 78% 80%, transparent 80%),
    radial-gradient(circle at 30% 22%, rgba(54,244,255,.28), transparent 30%),
    linear-gradient(135deg, rgba(54,244,255,.30), rgba(255,67,222,.22), rgba(255,225,90,.20));
}

.tetrisThumb span {
  background: linear-gradient(90deg, var(--cyan), var(--pink), var(--amber));
  box-shadow: 0 0 50px rgba(54,244,255,.46);
}

.picrossThumb {
  background:
    linear-gradient(90deg, transparent 0 18%, rgba(255,255,255,.08) 18% 20%, transparent 20% 38%, rgba(255,255,255,.08) 38% 40%, transparent 40% 58%, rgba(255,255,255,.08) 58% 60%, transparent 60% 78%, rgba(255,255,255,.08) 78% 80%, transparent 80%),
    linear-gradient(0deg, transparent 0 18%, rgba(255,255,255,.08) 18% 20%, transparent 20% 38%, rgba(255,255,255,.08) 38% 40%, transparent 40% 58%, rgba(255,255,255,.08) 58% 60%, transparent 60% 78%, rgba(255,255,255,.08) 78% 80%, transparent 80%),
    radial-gradient(circle at 50% 45%, rgba(255, 214, 107, .58), transparent 28%),
    linear-gradient(135deg, rgba(255,214,107,.26), rgba(82,236,255,.16), rgba(255,255,255,.08));
}

.picrossThumb span {
  font-family: "Hiragino Mincho ProN", "Yu Mincho", serif;
  font-size: 66px;
  color: #151515;
  background: radial-gradient(circle at 35% 25%, #fff5c7, var(--amber));
  box-shadow: 0 0 50px rgba(255,214,107,.46);
}

.stackThumb {
  background:
    linear-gradient(180deg, transparent 0 22%, rgba(255,255,255,.08) 22% 24%, transparent 24% 40%, rgba(255,255,255,.08) 40% 42%, transparent 42% 58%, rgba(255,255,255,.08) 58% 60%, transparent 60% 76%, rgba(255,255,255,.08) 76% 78%, transparent 78%),
    radial-gradient(circle at 50% 78%, rgba(124,255,128,.28), transparent 28%),
    linear-gradient(135deg, rgba(55,248,255,.28), rgba(124,255,128,.22), rgba(255,225,107,.18));
}

.stackThumb span {
  background: linear-gradient(180deg, var(--cyan), var(--green), var(--amber));
  box-shadow: 0 0 50px rgba(124,255,128,.42);
  letter-spacing: .04em;
}

.fieldThumb {
  background:
    radial-gradient(circle at 30% 40%, rgba(55,248,255,.45), transparent 22%),
    radial-gradient(circle at 68% 58%, rgba(255,61,242,.4), transparent 26%),
    radial-gradient(circle at 50% 50%, rgba(255,225,107,.18), transparent 40%),
    linear-gradient(135deg, rgba(8,12,36,.9), rgba(3,4,12,.95));
}

.fieldThumb span {
  font-size: 64px;
  color: #041018;
  background: linear-gradient(135deg, var(--cyan), var(--pink), var(--amber));
  box-shadow: 0 0 54px rgba(255,61,242,.42);
}

.voidThumb {
  background:
    radial-gradient(circle at 50% 48%, rgba(55,248,255,.55), transparent 18%),
    radial-gradient(circle at 50% 48%, rgba(255,61,242,.0), rgba(255,61,242,.22) 28%, transparent 52%),
    conic-gradient(from 120deg, rgba(55,248,255,.15), rgba(255,61,242,.2), rgba(255,225,107,.12), rgba(55,248,255,.15)),
    linear-gradient(160deg, #050814, #02030a);
}

.voidThumb span {
  font-size: 42px;
  letter-spacing: .12em;
  color: #041018;
  background: linear-gradient(135deg, var(--cyan), #a78bfa, var(--pink));
  box-shadow: 0 0 54px rgba(55,248,255,.45);
}

.liminalThumb {
  background:
    repeating-linear-gradient(
      90deg,
      rgba(201, 180, 106, .35) 0 10px,
      rgba(140, 120, 60, .25) 10px 12px
    ),
    linear-gradient(180deg, #d4c07a 0%, #a89048 40%, #3a472c 40%, #2a3420 100%);
}

.liminalThumb span {
  font-size: 40px;
  letter-spacing: .08em;
  color: #1a160c;
  background: linear-gradient(180deg, #efe6c0, #c9b46a);
  box-shadow: 0 0 40px rgba(201, 180, 106, .4);
}

.pendulumThumb {
  background:
    radial-gradient(circle at 50% 78%, rgba(56, 189, 248, .30) 0 22%, transparent 60%),
    linear-gradient(180deg, #141c2b 0%, #0b0f17 100%);
}

.pendulumThumb span {
  font-size: 44px;
  color: #06202e;
  background: linear-gradient(140deg, #7dd3fc, #38bdf8 45%, #fb7185);
  box-shadow: 0 0 44px rgba(56, 189, 248, .45);
}

.body { padding: 22px; }
.tag {
  margin: 0 0 8px;
  color: var(--amber);
  font-size: 12px;
  font-weight: 900;
  letter-spacing: .14em;
  text-transform: uppercase;
}

.card h3 {
  margin: 0;
  font-size: clamp(23px, 3vw, 32px);
  letter-spacing: -.04em;
}

.body p:not(.tag) {
  min-height: 84px;
  margin: 12px 0 18px;
  color: var(--muted);
  line-height: 1.7;
}

.play {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-width: 116px;
  min-height: 44px;
  padding: 11px 24px;
  border-radius: 999px;
  color: #031019;
  background: linear-gradient(90deg, var(--cyan), var(--green), var(--amber));
  font-weight: 1000;
  letter-spacing: .14em;
  text-decoration: none;
  box-shadow: 0 0 26px rgba(55,248,255,.34);
}

.play:hover { filter: brightness(1.08); transform: translateY(-1px); }

footer {
  width: min(1120px, calc(100% - 32px));
  margin: 0 auto 34px;
  color: rgba(226, 238, 255, .52);
  text-align: center;
  font-size: 13px;
}


/* ── セクション ───────────────────────────────── */
.section {
  position: relative;
  z-index: 1;
  width: min(1120px, calc(100% - 32px));
  margin: 0 auto 64px;
}

.sectionTitle {
  margin: 0 0 4px;
  font-size: 13px;
  font-weight: 900;
  letter-spacing: .28em;
  text-transform: uppercase;
  color: var(--cyan);
}

.sectionLead {
  margin: 0 0 20px;
  color: var(--muted);
  font-size: 14px;
  line-height: 1.75;
}

.sectionTitle + .grid { margin-top: 18px; }

/* ── アーカイブ (GitHub へのリンク一覧) ────────── */
.archive {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.archive a {
  display: grid;
  grid-template-columns: 64px minmax(0, 1fr) auto;
  grid-template-areas:
    "year name  arrow"
    "year desc  arrow";
  align-items: center;
  gap: 2px 16px;
  padding: 18px 22px;
  border: 1px solid rgba(255,255,255,.1);
  border-radius: 18px;
  background: linear-gradient(160deg, rgba(18, 26, 62, .55), rgba(6, 8, 22, .6));
  text-decoration: none;
  color: inherit;
  transition: border-color .15s, transform .1s, box-shadow .15s;
}

.archive a:hover {
  border-color: rgba(55,248,255,.4);
  transform: translateY(-2px);
  box-shadow: 0 18px 50px rgba(0,0,0,.35), 0 0 24px rgba(55,248,255,.1);
}

.archive .year {
  grid-area: year;
  align-self: center;
  color: var(--amber);
  font-size: 13px;
  font-weight: 900;
  letter-spacing: .06em;
}

.archive .name {
  grid-area: name;
  font-size: 19px;
  font-weight: 800;
  letter-spacing: -.02em;
}

.archive .desc {
  grid-area: desc;
  color: var(--muted);
  font-size: 13.5px;
  line-height: 1.65;
}

.archive .arrow {
  grid-area: arrow;
  align-self: center;
  color: var(--cyan);
  font-size: 20px;
  font-weight: 900;
}

footer a { color: var(--cyan); }

@media (max-width: 900px) {
  .grid { grid-template-columns: 1fr; }
  .thumb { height: 170px; }
  .body p:not(.tag) { min-height: 0; }

  .archive a {
    grid-template-columns: minmax(0, 1fr) auto;
    grid-template-areas:
      "year  arrow"
      "name  arrow"
      "desc  desc";
    gap: 4px 12px;
    padding: 16px 18px;
  }
}