:root {
  --bg: #f4f7fb;
  --card-bg: #fff;
  --text: #182230;
  --muted: #667085;
  --card-border: #d0d5dd;
  --accent: #5b21b6;
  --accent2: #db2777;
  --grad: linear-gradient(120deg, var(--accent), var(--accent2));
  --btn-c1: #6d28d9;
  --btn-c2: #db2777;
  --btn-grad: linear-gradient(120deg, var(--btn-c1), var(--btn-c2));
  --danger: #dc2626;
  --hero-grid: rgba(20, 20, 40, 0.05);
  --p1-color: #2563eb;
  --p2-color: #db2777;
  --p3-color: #16a34a;
  --p4-color: #d97706;
  --cell-size: 24px;
}
:root[data-theme="dark"] {
  --bg: #111018;
  --card-bg: #1d1a28;
  --text: #f0edf7;
  --muted: #b5aec5;
  --card-border: #383249;
  --accent: #b794f4;
  --accent2: #f472b6;
  --btn-c1: #8b5cf6;
  --btn-c2: #ec4899;
  --danger: #fb7185;
  --hero-grid: rgba(255, 255, 255, 0.06);
  --p1-color: #60a5fa;
  --p2-color: #f472b6;
  --p3-color: #4ade80;
  --p4-color: #fbbf24;
}
* { box-sizing: border-box; }
body {
  margin: 0;
  font-family: "Hiragino Sans", "Yu Gothic", Meiryo, sans-serif;
  background-color: var(--bg);
  background-image:
    radial-gradient(circle, var(--hero-grid) 1px, transparent 1px),
    radial-gradient(900px circle at 15% -10%, color-mix(in srgb, var(--accent) 12%, transparent), transparent 55%),
    radial-gradient(800px circle at 100% 10%, color-mix(in srgb, var(--accent2) 9%, transparent), transparent 55%);
  background-size: 22px 22px, auto, auto;
  background-attachment: fixed;
  color: var(--text);
  text-align: center;
  display: flex;
  flex-direction: column;
  align-items: center;
  min-height: 100vh;
}
.site-nav { width: 100%; max-width: 1040px; margin: auto; padding: 12px 16px; text-align: left; }
.site-nav a, footer a { color: var(--accent); text-decoration: none; }
.site-header { padding: 4px 16px; text-align: center; }
.site-header h1 { margin: 8px 0; font-size: 2rem; font-weight: 800; background: var(--grad); -webkit-background-clip: text; background-clip: text; color: transparent; }
.site-header p, .status, .label { color: var(--muted); }
.ad-slot { width: 100%; min-height: 56px; max-width: 728px; margin: 10px auto; display: flex; align-items: center; justify-content: center; background: repeating-linear-gradient(45deg, #eee, #eee 10px, #e2e2e2 10px, #e2e2e2 20px); color: #999; font-size: .8rem; border-radius: 8px; }
:root[data-theme="dark"] .ad-slot { background: repeating-linear-gradient(45deg, #1c1c20, #1c1c20 10px, #232328 10px, #232328 20px); color: #9a9aa2; }
main { width: 100%; max-width: 1080px; margin: auto; padding: 12px 16px 36px; }
.hidden { display: none !important; }
.panel { width: 100%; max-width: 700px; margin: 0 auto 16px; padding: 20px; background: var(--card-bg); border: 1px solid var(--card-border); border-radius: 12px; box-shadow: 0 4px 16px rgba(0, 0, 0, .06); text-align: center; }
.panel h2, .panel h3 { margin-top: 0; }
.text-input, select { padding: 10px; border: 1px solid var(--card-border); border-radius: 7px; background: var(--card-bg); color: var(--text); font: inherit; text-align: center; }
.panel > .text-input { width: min(100%, 260px); display: block; margin: .5rem auto 1rem; }
.online-choice { display: flex; flex-direction: column; align-items: center; gap: 1rem; margin-top: 1rem; }
.join-row { display: flex; flex-wrap: wrap; justify-content: center; align-items: center; gap: .5rem; }
.join-row .text-input { width: 140px; text-transform: uppercase; letter-spacing: .14em; }
.result-actions { display: flex; flex-wrap: wrap; justify-content: center; gap: 12px; margin-top: 16px; }
.primary, .link-button { font: inherit; font-weight: bold; cursor: pointer; border-radius: 8px; transition: transform .15s ease, box-shadow .15s ease; }
.primary { display: inline-block; border: 0; padding: .75rem 1rem; background: var(--btn-grad); color: #fff; }
.primary:hover:not(:disabled) { transform: translateY(-1px); box-shadow: 0 6px 16px color-mix(in srgb, var(--btn-c1) 35%, transparent); }
.link-button { display: inline-block; border: 0; padding: .35rem; background: none; color: var(--accent); text-decoration: underline; }
.secondary-btn { display: inline-flex; align-items: center; justify-content: center; border: 1px solid var(--accent); border-radius: 8px; padding: .75rem 1rem; background: transparent; color: var(--accent); font: inherit; font-weight: bold; text-decoration: none; cursor: pointer; transition: transform .15s ease, box-shadow .15s ease; }
.secondary-btn:hover { transform: translateY(-1px); box-shadow: 0 6px 16px color-mix(in srgb, var(--accent) 25%, transparent); }
button:disabled { opacity: .5; cursor: not-allowed; transform: none; box-shadow: none; }
.cell:disabled { opacity: 1; }
.error { color: var(--danger); min-height: 1.2em; }
.host-code { padding-bottom: 1rem; margin-bottom: 1rem; border-bottom: 1px solid var(--card-border); }
.room-code { display: block; color: var(--accent); font-size: 2rem; font-weight: bold; letter-spacing: .2em; margin: .3rem 0; }
.overlay { position: fixed; inset: 0; z-index: 10; display: flex; align-items: center; justify-content: center; background: #0009; }
.overlay-card { width: 390px; max-width: 90%; max-height: 85vh; overflow: auto; padding: 1.5rem; border-radius: 12px; background: var(--card-bg); border: 1px solid var(--card-border); text-align: center; }
.result-title { font-size: 1.35rem; font-weight: bold; }
.result-meta { margin: .2rem 0; color: var(--muted); font-size: .92rem; }
.roster, .result-scores { list-style: none; padding: 0; margin: 10px auto; max-width: 400px; }
.roster li, .result-scores li { margin: 6px 0; padding: 8px; border-left: 5px solid var(--muted); border-radius: 6px; text-align: left; font-weight: bold; background: color-mix(in srgb, var(--accent) 8%, var(--card-bg)); }
.p1 { border-color: var(--p1-color) !important; }
.p2 { border-color: var(--p2-color) !important; }
.p3 { border-color: var(--p3-color) !important; }
.p4 { border-color: var(--p4-color) !important; }
.scores { display: flex; gap: 8px; justify-content: center; flex-wrap: wrap; margin: 12px 0; }
.score { padding: 8px 10px; border-left: 5px solid; border-radius: 8px; font-weight: bold; background: var(--card-bg); box-shadow: 0 2px 8px rgba(0, 0, 0, .06); }
.flag-controls { display: flex; gap: 10px; justify-content: center; align-items: center; flex-wrap: wrap; margin: 8px 0 2px; }
.flag-controls .secondary-btn[aria-pressed="true"] { color: #fff; background: var(--btn-grad); border-color: transparent; }
.flag-note { margin: 6px 0; color: var(--muted); font-size: .9rem; }
.board-scroll { overflow-x: auto; padding: 10px; }
.board { display: grid; gap: 2px; width: max-content; margin: auto; padding: 7px; background: #64748b; border: 3px solid #475569; border-radius: 8px; }
.cell { width: var(--cell-size); height: var(--cell-size); padding: 0; border: 1px outset #f8fafc; border-radius: 2px; background: #cbd5e1; font-weight: 800; font-size: 14px; cursor: pointer; }
.cell.targeted:not(:disabled) { background: #ddd6fe; }
.cell.opened { border: 1px solid #94a3b8; background: #e2e8f0; cursor: default; }
.cell.flagged { background: #fef3c7; color: #b91c1c; }
.cell.p1 { background: color-mix(in srgb, var(--p1-color) 25%, var(--card-bg)); }
.cell.p2 { background: color-mix(in srgb, var(--p2-color) 25%, var(--card-bg)); }
.cell.p3 { background: color-mix(in srgb, var(--p3-color) 25%, var(--card-bg)); }
.cell.p4 { background: color-mix(in srgb, var(--p4-color) 25%, var(--card-bg)); }
.cell.mine { background: #fecaca; }
.board.is-frozen { opacity: .72; }
.number-1 { color: #2563eb; }
.number-2 { color: #15803d; }
.number-3 { color: #dc2626; }
.number-4 { color: #4338ca; }
.number-5 { color: #991b1b; }
.number-6 { color: #0f766e; }
.number-7 { color: #111827; }
.number-8 { color: #475569; }
.howto { text-align: left; }
.howto h2 { text-align: center; }
.howto li { margin: 8px 0; line-height: 1.5; }
.connection-health { position: sticky; top: .5rem; z-index: 20; margin: .5rem auto; padding: .7rem 1rem; max-width: 42rem; border: 1px solid #d97706; border-radius: .6rem; background: #fffbeb; color: #92400e; font-weight: 700; text-align: center; }
footer { width: 100%; margin-top: auto; padding: 20px; color: var(--muted); font-size: .85rem; }
@media (max-width: 480px) {
  :root { --cell-size: 22px; }
  .site-header h1 { font-size: 1.55rem; }
  .panel { padding: 16px 10px; }
  .room-code { font-size: 1.6rem; }
  .result-actions { flex-direction: column; }
}