/* ==========================================================================
   Open Gate NIIGATA 2026 — base.css
   リセット・CSSカスタムプロパティ・タイポグラフィ
   ========================================================================== */

:root {
  /* ---------- Brand colors ---------- */
  --opg-primary:   #0a0a14;
  --opg-secondary: #faf8f4;
  --opg-accent:    #e84b3c;

  /* ---------- 7予選＋FINAL用アクセントカラー（Pastel系・logo由来） ---------- */
  --c-red:    oklch(64% 0.22 28);
  --c-orange: oklch(75% 0.18 55);
  --c-yellow: oklch(85% 0.16 90);
  --c-green:  oklch(72% 0.16 150);
  --c-teal:   oklch(70% 0.14 210);
  --c-blue:   oklch(60% 0.15 240);
  --c-indigo: oklch(55% 0.18 285);
  --c-pink:   oklch(72% 0.18 350);

  /* ---------- Logo-derived ---------- */
  --opg-logo-blue-deep: #1670b8;
  --opg-logo-blue:      #2da3da;
  --opg-logo-red:       #e84b3c;

  /* ---------- Surface / Text ---------- */
  --opg-paper:     #faf8f4;
  --opg-paper-2:   #f2efe8;
  --opg-paper-3:   #e8e3d8;
  --opg-bg:        #ffffff;
  --opg-bg-soft:   #faf8f3;
  --opg-text:      #0a0a14;
  --opg-ink:       #0a0a14;
  --opg-ink-soft:  #2a2a38;
  --opg-text-mute: #6b6b7a;
  --opg-ink-mute:  #6b6b7a;
  --opg-border:    rgba(10, 10, 20, 0.08);
  --opg-border-strong: rgba(10, 10, 20, 0.18);

  /* ---------- Gradients ---------- */
  --opg-grad-rainbow:
    linear-gradient(110deg,
      oklch(64% 0.22 28) 0%,
      oklch(75% 0.18 55) 14%,
      oklch(85% 0.16 90) 28%,
      oklch(72% 0.16 150) 42%,
      oklch(70% 0.14 210) 56%,
      oklch(60% 0.15 240) 70%,
      oklch(55% 0.18 285) 85%,
      oklch(72% 0.18 350) 100%);

  --opg-grad-poster:
    conic-gradient(from 220deg at 30% 60%,
      oklch(64% 0.22 28) 0deg,
      oklch(78% 0.18 55) 50deg,
      oklch(86% 0.16 95) 100deg,
      oklch(72% 0.16 150) 150deg,
      oklch(68% 0.14 210) 200deg,
      oklch(55% 0.18 285) 260deg,
      oklch(72% 0.18 350) 320deg,
      oklch(64% 0.22 28) 360deg);

  --opg-shadow-1: 0 1px 2px rgba(10,10,20,0.04), 0 4px 12px rgba(10,10,20,0.04);
  --opg-shadow-2: 0 2px 6px rgba(10,10,20,0.05), 0 16px 40px rgba(10,10,20,0.1);
  --opg-shadow-3: 0 4px 14px rgba(10,10,20,0.08), 0 30px 80px rgba(80,60,140,0.18);

  /* ---------- Typography ---------- */
  --opg-font-ja:   "Zen Kaku Gothic New", "Noto Sans JP", system-ui, sans-serif;
  --opg-font-en:   "Space Grotesk", "Zen Kaku Gothic New", system-ui, sans-serif;
  --opg-font-mono: "JetBrains Mono", ui-monospace, monospace;

  --opg-text-xs:   13px;
  --opg-text-sm:   14px;
  --opg-text-base: 16px;
  --opg-text-md:   17px;

  /* ---------- Spacing / Layout ---------- */
  --opg-container: 1240px;
  --opg-gutter: clamp(20px, 4vw, 56px);
  --opg-radius:    12px;
  --opg-radius-sm: 10px;
  --opg-radius-md: 16px;
  --opg-radius-lg: 24px;
  --opg-radius-xl: 32px;
  --opg-radius-pill: 999px;
}

/* ---------- Reset ---------- */
*, *::before, *::after { box-sizing: border-box; }
html {
  -webkit-text-size-adjust: 100%;
  scroll-behavior: smooth;
  scroll-padding-top: 72px;
}
body {
  margin: 0;
  font-family: var(--opg-font-ja);
  font-size: var(--opg-text-base);
  color: var(--opg-text);
  background: var(--opg-paper);
  line-height: 1.7;
  font-feature-settings: "palt";
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
  overflow-x: hidden;
}
img, svg, video { max-width: 100%; height: auto; display: block; }
a { color: inherit; text-decoration: none; }
button { font: inherit; cursor: pointer; background: none; border: 0; padding: 0; color: inherit; }
h1, h2, h3, h4, h5, h6, p, figure { margin: 0; }
ul, ol { margin: 0; padding: 0; list-style: none; }
::selection { background: var(--opg-ink); color: var(--opg-paper); }

/* ---------- Utility ---------- */
.opg-container {
  width: 100%;
  max-width: var(--opg-container);
  margin-inline: auto;
  padding-inline: var(--opg-gutter);
}

.opg-eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 12px;
  font-family: var(--opg-font-en);
  font-size: var(--opg-text-xs);
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--opg-ink-soft);
  font-weight: 700;
}
.opg-eyebrow::before {
  content: "";
  width: 28px;
  height: 1px;
  background: currentColor;
}

.opg-section-head {
  display: flex;
  align-items: end;
  justify-content: space-between;
  gap: 40px;
  margin-bottom: clamp(40px, 5vw, 72px);
  flex-wrap: wrap;
}
.opg-section-head__lead {
  max-width: 420px;
  font-size: var(--opg-text-base);
  color: var(--opg-ink-soft);
  margin: 0;
  line-height: 1.9;
}
.opg-section-head > div > .opg-section-title-en:first-child {
  margin-top: 0;
}
.opg-section-title-en {
  font-family: var(--opg-font-en);
  font-size: clamp(40px, 6vw, 88px);
  font-weight: 700;
  letter-spacing: -0.03em;
  line-height: 1.02;
  margin: 10px 0 6px;
}
.opg-section-title-jp {
  font-size: 20px;
  font-weight: 700;
  color: var(--opg-ink-mute);
  margin: 12px 0 0;
  letter-spacing: 0.08em;
}

/* ---------- Section base rhythm ---------- */
.opg-section {
  position: relative;
  padding: clamp(80px, 10vw, 140px) 0;
}

/* ---------- Buttons ---------- */
.opg-btn {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  padding: 16px 28px;
  border-radius: var(--opg-radius-pill);
  font-weight: 700;
  font-size: var(--opg-text-sm);
  letter-spacing: 0.02em;
  border: 0;
  transition: transform 0.2s ease, box-shadow 0.2s ease, opacity 0.15s ease;
}
.opg-btn:hover { transform: translateY(-2px); }
.opg-btn--lg { padding: 20px 36px; font-size: var(--opg-text-base); }
.opg-btn--primary {
  background: #fff;
  color: var(--opg-ink);
  box-shadow: 0 8px 32px rgba(0,0,0,0.18);
}
.opg-btn--ghost {
  background: rgba(255,255,255,0.08);
  color: #fff;
  border: 1px solid rgba(255,255,255,0.3);
  backdrop-filter: blur(10px);
}
.opg-btn--rainbow {
  background: var(--opg-grad-rainbow);
  color: #fff;
  box-shadow: 0 12px 40px -8px oklch(60% 0.2 280 / 0.5);
  position: relative;
  overflow: hidden;
}
.opg-btn--rainbow::after {
  content: "";
  position: absolute;
  inset: 0;
  background: linear-gradient(180deg, rgba(255,255,255,0.15), transparent 50%);
  pointer-events: none;
}
.opg-btn--dark {
  background: var(--opg-ink);
  color: #fff;
  box-shadow: 0 8px 32px rgba(10,10,20,0.3);
}
.opg-btn--dark:hover {
  box-shadow: 0 12px 40px rgba(10,10,20,0.38);
}

.opg-link-arrow {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-size: var(--opg-text-sm);
  font-weight: 700;
  color: var(--opg-ink-soft);
  text-decoration: underline;
  text-underline-offset: 4px;
  text-decoration-thickness: 1.5px;
  text-decoration-color: var(--opg-border-strong);
  transition: color 0.2s ease;
}
.opg-link-arrow:hover { color: var(--opg-ink); }

/* ---------- Fade-in (JS adds .is-visible) ---------- */
.opg-fade {
  opacity: 0;
  transform: translateY(24px);
  transition: opacity 0.7s ease, transform 0.7s ease;
}
.opg-fade.is-visible {
  opacity: 1;
  transform: none;
}
@media (prefers-reduced-motion: reduce) {
  .opg-fade { opacity: 1; transform: none; transition: none; }
}