/* Shared every-visit arena intro gate (Game Review, Blunder Override, AI Coach, Sparring). */

@media (prefers-reduced-motion: reduce) {
  .arena-intro-backdrop,
  .arena-intro-stage,
  .arena-intro-seal,
  .arena-intro-eyebrow,
  .arena-intro-title,
  .arena-intro-copy,
  .arena-intro-modes,
  .arena-intro-note,
  .arena-intro-actions,
  .arena-intro-play,
  .arena-intro-stay,
  .arena-intro-hint {
    animation: none;
  }
}

/* Full-viewport gate: hide chrome that would peek past a page-shell overlay. */
body:has(.arena-intro:not([hidden])),
body:has(.puzzle-intro:not([hidden])) {
  overflow: hidden;
}
body:has(.arena-intro:not([hidden])) .site-footer,
body:has(.puzzle-intro:not([hidden])) .site-footer {
  display: none !important;
}

/* Arena intro gate — same dramatic splash as /puzzles (every visit).
   Mounted on document.body (see JS) so position:fixed is never trapped by
   .page-shell / transforms, and the backdrop covers the whole viewport. */
.arena-intro[hidden] {
  display: none !important;
}
.arena-intro {
  position: fixed;
  inset: 0;
  width: 100vw;
  width: 100dvw;
  height: 100vh;
  height: 100dvh;
  z-index: 10000;
  display: grid;
  place-items: center;
  padding: 24px;
  margin: 0;
}
.arena-intro-backdrop {
  position: absolute;
  inset: 0;
  background:
    radial-gradient(ellipse 70% 55% at 50% 38%, color-mix(in srgb, var(--gold) 16%, transparent), transparent 68%),
    radial-gradient(ellipse 90% 70% at 50% 100%, rgba(0, 0, 0, 0.55), transparent 55%),
    rgba(4, 4, 5, 0.82);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  animation: arena-intro-fade 0.4s ease;
}
.arena-intro-stage {
  position: relative;
  width: min(480px, 100%);
  padding: 2.6rem 2rem 2rem;
  border-radius: 20px;
  text-align: center;
  color: var(--cream);
  border: 1px solid color-mix(in srgb, var(--gold) 32%, var(--line-strong));
  background:
    radial-gradient(ellipse 85% 55% at 50% -12%, color-mix(in srgb, var(--gold) 22%, transparent), transparent 58%),
    linear-gradient(180deg, color-mix(in srgb, var(--paper) 92%, #fff 8%), var(--paper-2));
  overflow: hidden;
  box-shadow:
    0 0 0 1px rgba(255, 255, 255, 0.05) inset,
    0 1px 0 color-mix(in srgb, var(--gold) 35%, transparent) inset,
    0 0 60px color-mix(in srgb, var(--gold) 12%, transparent),
    0 32px 90px rgba(0, 0, 0, 0.58);
  animation: arena-intro-rise 0.55s cubic-bezier(0.22, 1, 0.36, 1);
}
.arena-intro-stage::before {
  content: "";
  position: absolute;
  inset: 0 0 auto 0;
  height: 1px;
  background: linear-gradient(
    90deg,
    transparent 4%,
    color-mix(in srgb, var(--gold) 55%, transparent) 30%,
    color-mix(in srgb, #fff 40%, transparent) 50%,
    color-mix(in srgb, var(--gold) 55%, transparent) 70%,
    transparent 96%
  );
  pointer-events: none;
}
.arena-intro-stage::after {
  content: "";
  position: absolute;
  inset: 10px;
  border-radius: 14px;
  border: 1px solid color-mix(in srgb, var(--gold) 12%, transparent);
  pointer-events: none;
}
.arena-intro-seal {
  display: grid;
  place-items: center;
  width: 88px;
  height: 88px;
  margin: 0 auto 1.15rem;
  border-radius: 50%;
  font-size: 2.55rem;
  line-height: 1;
  color: var(--gold-bright);
  background:
    radial-gradient(circle at 50% 42%, color-mix(in srgb, var(--gold) 22%, transparent), transparent 68%),
    color-mix(in srgb, var(--gold) 10%, transparent);
  box-shadow:
    0 0 0 1px color-mix(in srgb, var(--gold) 35%, transparent),
    0 0 28px color-mix(in srgb, var(--gold) 22%, transparent);
  filter: drop-shadow(0 0 14px color-mix(in srgb, var(--gold) 28%, transparent));
  animation:
    arena-intro-seal 0.7s cubic-bezier(0.22, 1, 0.36, 1) 0.05s both,
    arena-intro-breathe 3.6s ease-in-out 0.9s infinite;
}
.arena-intro-eyebrow {
  margin: 0 0 0.55rem;
  font-size: 0.68rem;
  font-weight: 800;
  letter-spacing: 0.22em;
  text-transform: uppercase;
  color: var(--gold);
  animation: arena-intro-rise 0.55s cubic-bezier(0.22, 1, 0.36, 1) 0.08s both;
}
.arena-intro-title {
  margin: 0 0 0.55rem;
  font-family: var(--font);
  font-size: clamp(2.15rem, 5.5vw, 2.75rem);
  font-weight: 800;
  letter-spacing: -0.04em;
  line-height: 1.05;
  color: var(--cream);
  animation: arena-intro-rise 0.55s cubic-bezier(0.22, 1, 0.36, 1) 0.12s both;
}
.arena-intro-copy {
  margin: 0 auto 1.15rem;
  max-width: 28ch;
  font-size: 1rem;
  line-height: 1.5;
  color: var(--muted);
  animation: arena-intro-rise 0.55s cubic-bezier(0.22, 1, 0.36, 1) 0.16s both;
}
.arena-intro-modes {
  list-style: none;
  margin: 0 auto 1.55rem;
  padding: 0.65rem 0.85rem;
  width: min(100%, 22rem);
  text-align: left;
  border-radius: 12px;
  border: 1px solid color-mix(in srgb, var(--gold) 16%, var(--line));
  background: color-mix(in srgb, var(--gold) 6%, rgba(0, 0, 0, 0.22));
  animation: arena-intro-rise 0.55s cubic-bezier(0.22, 1, 0.36, 1) 0.18s both;
}
.arena-intro-modes li {
  display: grid;
  grid-template-columns: 5.25rem 1fr;
  gap: 0.55rem 0.75rem;
  align-items: baseline;
  padding: 0.42rem 0.25rem;
  font-size: 0.84rem;
  line-height: 1.35;
  color: var(--muted);
}
.arena-intro-modes li + li {
  border-top: 1px solid color-mix(in srgb, var(--line) 80%, transparent);
}
.arena-intro-modes strong {
  font-size: 0.78rem;
  font-weight: 800;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--gold);
}
.arena-intro-note {
  position: relative;
  z-index: 1;
  margin: -0.35rem auto 1.15rem;
  max-width: 22rem;
  font-size: 0.82rem;
  line-height: 1.45;
  letter-spacing: 0.02em;
  color: color-mix(in srgb, var(--muted) 92%, var(--gold));
  animation: arena-intro-rise 0.55s cubic-bezier(0.22, 1, 0.36, 1) 0.2s both;
}
.arena-intro-actions {
  position: relative;
  z-index: 1;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 1.35rem;
  width: min(100%, 22rem);
  margin-inline: auto;
  animation: arena-intro-rise 0.55s cubic-bezier(0.22, 1, 0.36, 1) 0.22s both;
}
.arena-intro-actions .arena-intro-play,
.arena-intro-actions .arena-intro-stay {
  box-sizing: border-box;
  width: 100%;
  max-width: 22rem;
  margin-inline: auto;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  text-align: center;
}
.arena-intro-actions .arena-intro-play {
  animation:
    arena-intro-pulse 2.4s ease-in-out 1s infinite;
  min-width: 0;
  letter-spacing: 0.06em;
  font-size: 0.92rem;
  padding: 0.9rem 1.25rem;
}
.arena-intro-stay {
  appearance: none;
  padding: 0.72rem 1.1rem;
  border-radius: 10px;
  border: 1px solid color-mix(in srgb, var(--line) 88%, var(--gold));
  background: color-mix(in srgb, var(--paper) 72%, transparent);
  font: inherit;
  font-size: 0.82rem;
  font-weight: 700;
  letter-spacing: 0.05em;
  color: color-mix(in srgb, var(--muted) 78%, var(--cream-dim, var(--text)));
  cursor: pointer;
  transition:
    color 0.15s ease,
    border-color 0.15s ease,
    background 0.15s ease,
    box-shadow 0.15s ease;
}
.arena-intro-stay:hover,
.arena-intro-stay:focus-visible {
  color: var(--cream-dim, var(--text));
  border-color: color-mix(in srgb, var(--gold) 42%, var(--line));
  background: color-mix(in srgb, var(--gold) 8%, var(--paper));
  box-shadow: 0 0 0 1px color-mix(in srgb, var(--gold) 18%, transparent);
  outline: none;
}
html[data-theme="light"] .arena-intro-stay {
  background: rgba(255, 255, 255, 0.72);
  border-color: color-mix(in srgb, var(--line) 90%, var(--gold));
  color: color-mix(in srgb, var(--text) 72%, var(--muted));
}
html[data-theme="light"] .arena-intro-stay:hover,
html[data-theme="light"] .arena-intro-stay:focus-visible {
  color: var(--text);
  border-color: color-mix(in srgb, var(--gold) 40%, var(--line));
  background: color-mix(in srgb, var(--gold) 7%, #fff);
}
.arena-intro-play {
  position: relative;
  z-index: 1;
  min-width: 11.5rem;
  padding: 0.95rem 2.1rem;
  font-size: 1.05rem;
  font-weight: 800;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  animation:
    arena-intro-rise 0.55s cubic-bezier(0.22, 1, 0.36, 1) 0.22s both,
    arena-intro-pulse 2.4s ease-in-out 1s infinite;
  box-shadow:
    0 0 0 1px color-mix(in srgb, var(--gold-bright) 40%, transparent),
    0 10px 28px color-mix(in srgb, var(--gold) 28%, transparent);
}
.arena-intro-play:hover,
.arena-intro-play:focus-visible {
  box-shadow:
    0 0 0 1px color-mix(in srgb, var(--gold-bright) 55%, transparent),
    0 12px 36px color-mix(in srgb, var(--gold) 40%, transparent);
}
.arena-intro-hint {
  position: relative;
  z-index: 1;
  margin: 0.85rem 0 0;
  font-size: 0.72rem;
  letter-spacing: 0.04em;
  color: color-mix(in srgb, var(--muted) 88%, transparent);
  animation: arena-intro-rise 0.55s cubic-bezier(0.22, 1, 0.36, 1) 0.26s both;
}
.arena-intro-hint kbd {
  display: inline-block;
  padding: 0.1em 0.4em;
  border-radius: 4px;
  border: 1px solid color-mix(in srgb, var(--line) 90%, var(--gold));
  background: color-mix(in srgb, var(--paper) 70%, transparent);
  font-family: var(--font);
  font-size: 0.68rem;
  font-weight: 700;
  letter-spacing: 0.06em;
  color: var(--cream-dim, var(--muted));
}
html[data-theme="light"] .arena-intro-backdrop {
  background:
    radial-gradient(ellipse 70% 55% at 50% 38%, color-mix(in srgb, var(--gold) 12%, transparent), transparent 68%),
    rgba(15, 23, 42, 0.48);
}
html[data-theme="light"] .arena-intro-stage {
  border-color: color-mix(in srgb, var(--gold) 34%, var(--line));
  color: var(--text);
  background:
    radial-gradient(ellipse 85% 55% at 50% -12%, color-mix(in srgb, var(--gold) 14%, transparent), transparent 58%),
    linear-gradient(180deg, #fff, var(--paper-2));
  box-shadow:
    0 0 0 1px rgba(15, 23, 42, 0.04) inset,
    0 0 48px color-mix(in srgb, var(--gold) 10%, transparent),
    0 28px 72px rgba(15, 23, 42, 0.18);
}
html[data-theme="light"] .arena-intro-title {
  color: var(--text);
}
html[data-theme="light"] .arena-intro-seal {
  color: inherit;
  background:
    radial-gradient(circle at 50% 42%, color-mix(in srgb, var(--gold) 16%, transparent), transparent 68%),
    color-mix(in srgb, var(--gold) 8%, #fff);
}
html[data-theme="light"] .arena-intro-modes {
  background: rgba(24, 24, 27, 0.03);
  border-color: color-mix(in srgb, var(--gold) 22%, var(--line));
}
html[data-theme="light"] .arena-intro-hint kbd {
  color: var(--text);
  background: rgba(24, 24, 27, 0.04);
}
@keyframes arena-intro-fade {
  from { opacity: 0; }
  to { opacity: 1; }
}
@keyframes arena-intro-rise {
  from {
    opacity: 0;
    transform: translateY(16px) scale(0.96);
  }
  to {
    opacity: 1;
    transform: translateY(0) scale(1);
  }
}
@keyframes arena-intro-seal {
  from {
    opacity: 0;
    transform: scale(0.72);
  }
  to {
    opacity: 1;
    transform: scale(1);
  }
}
@keyframes arena-intro-breathe {
  0%, 100% { transform: scale(1); }
  50% { transform: scale(1.045); }
}
@keyframes arena-intro-pulse {
  0%, 100% {
    box-shadow:
      0 0 0 1px color-mix(in srgb, var(--gold-bright) 40%, transparent),
      0 10px 28px color-mix(in srgb, var(--gold) 28%, transparent);
  }
  50% {
    box-shadow:
      0 0 0 1px color-mix(in srgb, var(--gold-bright) 55%, transparent),
      0 12px 36px color-mix(in srgb, var(--gold) 42%, transparent),
      0 0 28px color-mix(in srgb, var(--gold) 22%, transparent);
  }
}