:root {
  --brand-blue: #2563eb;
  --brand-red: #ef4444;
  --brand-yellow: #fbbf24;
  --brand-green: #16a34a;
  --brand-ink: #10233e;
  --brand-copy: #4b5a6d;
  --brand-muted: #7c8797;
  --brand-line: rgba(148, 163, 184, 0.22);
  --brand-panel: rgba(255, 255, 255, 0.9);
  --brand-panel-strong: #ffffff;
  --brand-bg: #f8fafc;
  --brand-shadow: 0 24px 60px rgba(15, 23, 42, 0.08);
}

html {
  scroll-behavior: smooth;
}

body {
  background:
    radial-gradient(circle at top left, rgba(37, 99, 235, 0.1), transparent 28%),
    radial-gradient(circle at 85% 10%, rgba(239, 68, 68, 0.09), transparent 22%),
    radial-gradient(circle at 20% 78%, rgba(251, 191, 36, 0.09), transparent 22%),
    radial-gradient(circle at 82% 74%, rgba(22, 163, 74, 0.08), transparent 20%),
    linear-gradient(180deg, #ffffff 0%, var(--brand-bg) 100%);
  color: var(--brand-ink);
}

body::before {
  content: "";
  position: fixed;
  inset: 0;
  pointer-events: none;
  background-image:
    linear-gradient(rgba(255, 255, 255, 0.55), rgba(255, 255, 255, 0.55)),
    radial-gradient(rgba(15, 23, 42, 0.025) 0.8px, transparent 0.8px);
  background-size: auto, 18px 18px;
  opacity: 0.55;
  z-index: -1;
}

.brand-header {
  background: rgba(255, 255, 255, 0.86);
  border-color: var(--brand-line);
  box-shadow: 0 12px 30px rgba(15, 23, 42, 0.05);
}

.brand-lockup {
  display: inline-flex;
  align-items: center;
  gap: 0.7rem;
  min-width: 0;
}

.brand-symbol {
  height: 52px;
  width: 52px;
  flex: none;
}

.brand-logo-text {
  min-width: 0;
  line-height: 1;
}

.brand-logo-row {
  display: flex;
  align-items: baseline;
  gap: 0.22rem;
  font-size: 1.95rem;
  font-weight: 700;
  letter-spacing: 0.02em;
  white-space: nowrap;
}

.brand-logo-subtitle {
  margin-top: 0.2rem;
  display: block;
  font-size: 0.78rem;
  letter-spacing: 0.09em;
  color: var(--brand-muted);
  white-space: nowrap;
}

.brand-letter-blue { color: var(--brand-blue); }
.brand-letter-red { color: var(--brand-red); }
.brand-letter-yellow { color: var(--brand-yellow); }
.brand-letter-green { color: var(--brand-green); }

.brand-logo {
  height: 48px;
  width: auto;
}

.brand-logo-lg {
  height: 74px;
  width: auto;
}

.brand-link {
  color: var(--brand-copy);
  transition: color 160ms ease;
}

.brand-link:hover,
.brand-link:focus-visible,
.brand-link-active {
  color: var(--brand-blue);
}

.brand-nav {
  display: flex;
  align-items: center;
  gap: 1.5rem;
}

.brand-dropdown {
  position: relative;
}

.brand-dropdown-toggle {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
}

.brand-dropdown-menu {
  position: absolute;
  top: calc(100% + 0.8rem);
  left: 0;
  min-width: 250px;
  padding: 0.8rem;
  border: 1px solid var(--brand-line);
  border-radius: 1rem;
  background: rgba(255, 255, 255, 0.96);
  box-shadow: 0 18px 40px rgba(15, 23, 42, 0.08);
  opacity: 0;
  visibility: hidden;
  transform: translateY(8px);
  transition: opacity 150ms ease, transform 150ms ease, visibility 150ms ease;
  z-index: 60;
}

.brand-dropdown:hover .brand-dropdown-menu,
.brand-dropdown:focus-within .brand-dropdown-menu {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
}

.brand-dropdown-item {
  display: block;
  padding: 0.8rem 0.9rem;
  border-radius: 0.9rem;
  color: var(--brand-ink);
  transition: background 150ms ease, color 150ms ease;
}

.brand-dropdown-item:hover,
.brand-dropdown-item:focus-visible {
  background: #eff6ff;
  color: var(--brand-blue);
}

.brand-dropdown-label {
  display: block;
  font-size: 0.94rem;
  font-weight: 600;
}

.brand-dropdown-copy {
  display: block;
  margin-top: 0.18rem;
  font-size: 0.78rem;
  color: var(--brand-muted);
}

.brand-button {
  border-radius: 999px;
  font-weight: 600;
  transition: transform 180ms ease, box-shadow 180ms ease, opacity 180ms ease;
}

.brand-button:hover,
.brand-button:focus-visible {
  transform: translateY(-1px);
}

.brand-button-primary {
  background: linear-gradient(135deg, var(--brand-blue), var(--brand-green));
  color: #fff;
  box-shadow: 0 14px 30px rgba(37, 99, 235, 0.22);
}

.brand-button-secondary {
  background: rgba(255, 255, 255, 0.72);
  border: 1px solid rgba(37, 99, 235, 0.16);
  color: var(--brand-ink);
}

.brand-panel {
  background: linear-gradient(180deg, rgba(255, 255, 255, 0.96), rgba(255, 255, 255, 0.88));
  border: 1px solid var(--brand-line);
  box-shadow: var(--brand-shadow);
}

.brand-panel-soft {
  background: linear-gradient(180deg, rgba(255, 255, 255, 0.74), rgba(255, 255, 255, 0.62));
  border: 1px solid var(--brand-line);
}

.brand-hero {
  position: relative;
}

.brand-hero::after {
  content: "";
  position: absolute;
  inset: 0;
  background:
    radial-gradient(circle at 12% 25%, rgba(37, 99, 235, 0.16), transparent 24%),
    radial-gradient(circle at 92% 10%, rgba(239, 68, 68, 0.14), transparent 20%),
    radial-gradient(circle at 24% 88%, rgba(251, 191, 36, 0.14), transparent 20%),
    radial-gradient(circle at 84% 84%, rgba(22, 163, 74, 0.14), transparent 18%);
  pointer-events: none;
}

.brand-chip {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.45rem 1rem;
  border-radius: 999px;
  border: 1px solid rgba(37, 99, 235, 0.14);
  background: rgba(255, 255, 255, 0.72);
  color: var(--brand-muted);
}

.brand-heading {
  color: var(--brand-ink);
}

.brand-subtle {
  color: var(--brand-copy);
}

.brand-section-border {
  border-color: var(--brand-line);
}

.brand-gradient-text {
  background: linear-gradient(90deg, var(--brand-blue), var(--brand-red), var(--brand-yellow), var(--brand-green));
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}

.brand-accent-bar {
  height: 4px;
  width: 84px;
  border-radius: 999px;
  background: linear-gradient(90deg, var(--brand-blue), var(--brand-red), var(--brand-yellow), var(--brand-green));
}

.brand-grid-glow {
  position: relative;
  overflow: hidden;
}

.brand-grid-glow::before {
  content: "";
  position: absolute;
  inset: auto -30% -45% auto;
  width: 220px;
  height: 220px;
  background: radial-gradient(circle, rgba(37, 99, 235, 0.14), transparent 65%);
  pointer-events: none;
}

.brand-footer {
  background: rgba(255, 255, 255, 0.72);
  border-color: var(--brand-line);
}

.brand-legal {
  background: rgba(255, 255, 255, 0.78);
}

.tool-hero-grid {
  display: grid;
  gap: 2rem;
}

.tool-list-card {
  display: block;
  border-radius: 1.5rem;
  border: 1px solid var(--brand-line);
  background: linear-gradient(180deg, rgba(255, 255, 255, 0.97), rgba(255, 255, 255, 0.9));
  box-shadow: var(--brand-shadow);
  transition: transform 180ms ease, box-shadow 180ms ease;
}

.tool-list-card:hover,
.tool-list-card:focus-visible {
  transform: translateY(-2px);
  box-shadow: 0 28px 60px rgba(15, 23, 42, 0.12);
}

.tool-metric {
  border-radius: 1rem;
  border: 1px solid rgba(37, 99, 235, 0.1);
  background: linear-gradient(180deg, #ffffff, #f8fbff);
  padding: 1rem;
}

.tool-result {
  border-radius: 1.5rem;
  border: 1px solid rgba(37, 99, 235, 0.14);
  background: linear-gradient(180deg, #ffffff, #f8fbff);
  padding: 1.25rem;
}

.tool-result strong {
  color: var(--brand-ink);
}

.tool-badge {
  display: inline-flex;
  align-items: center;
  gap: 0.45rem;
  padding: 0.42rem 0.85rem;
  border-radius: 999px;
  background: #eff6ff;
  color: var(--brand-blue);
  font-size: 0.78rem;
  font-weight: 600;
}

.game-board {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 0.85rem;
}

.game-toolbar {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  gap: 1.25rem;
}

.game-mode-switch {
  display: inline-flex;
  flex-wrap: wrap;
  gap: 0.75rem;
}

.game-mode-option input {
  position: absolute;
  opacity: 0;
  pointer-events: none;
}

.game-mode-option span {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-width: 132px;
  padding: 0.8rem 1rem;
  border: 1px solid rgba(37, 99, 235, 0.14);
  border-radius: 999px;
  background: linear-gradient(180deg, #ffffff, #f8fbff);
  color: var(--brand-copy);
  font-size: 0.92rem;
  font-weight: 600;
  transition: border-color 160ms ease, box-shadow 160ms ease, color 160ms ease, transform 160ms ease;
  cursor: pointer;
}

.game-mode-option input:checked + span {
  color: var(--brand-blue);
  border-color: rgba(37, 99, 235, 0.32);
  box-shadow: 0 14px 28px rgba(37, 99, 235, 0.12);
}

.game-scoreboard {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 0.75rem;
  min-width: min(100%, 280px);
}

.game-score-card {
  border-radius: 1rem;
  border: 1px solid rgba(37, 99, 235, 0.12);
  background: linear-gradient(180deg, #ffffff, #f8fbff);
  padding: 0.9rem 0.75rem;
  text-align: center;
}

.game-score-card strong {
  display: block;
  color: var(--brand-ink);
  font-size: 1.35rem;
  line-height: 1;
}

.game-score-card span {
  display: block;
  margin-top: 0.35rem;
  color: var(--brand-muted);
  font-size: 0.78rem;
  text-transform: uppercase;
  letter-spacing: 0.08em;
}

.game-turn-strip {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 0.75rem;
}

.game-turn-pill {
  border-radius: 999px;
  border: 1px solid rgba(37, 99, 235, 0.12);
  background: rgba(255, 255, 255, 0.74);
  padding: 0.75rem 1rem;
  text-align: center;
  color: var(--brand-copy);
  font-weight: 600;
}

.game-turn-pill-active {
  color: var(--brand-blue);
  border-color: rgba(37, 99, 235, 0.3);
  box-shadow: 0 14px 28px rgba(37, 99, 235, 0.1);
}

.game-cell {
  min-height: 100px;
  border: 1px solid rgba(37, 99, 235, 0.14);
  border-radius: 1.25rem;
  background: linear-gradient(180deg, #ffffff, #f8fbff);
  box-shadow: 0 12px 30px rgba(15, 23, 42, 0.06);
  font-size: 2rem;
  font-weight: 700;
  color: var(--brand-ink);
  transition: transform 160ms ease, box-shadow 160ms ease, border-color 160ms ease;
}

.game-cell:hover:not(:disabled),
.game-cell:focus-visible:not(:disabled) {
  transform: translateY(-1px);
  border-color: rgba(37, 99, 235, 0.28);
  box-shadow: 0 18px 34px rgba(15, 23, 42, 0.08);
}

.game-cell:disabled {
  cursor: default;
}

.game-cell-x {
  color: var(--brand-blue);
}

.game-cell-o {
  color: var(--brand-red);
}

.game-cell-winning {
  border-color: rgba(22, 163, 74, 0.35);
  background: linear-gradient(180deg, rgba(240, 253, 244, 0.98), rgba(220, 252, 231, 0.92));
  box-shadow: 0 18px 34px rgba(22, 163, 74, 0.14);
}

.game-status {
  border-radius: 1.25rem;
  border: 1px solid rgba(37, 99, 235, 0.14);
  background: linear-gradient(180deg, #ffffff, #f8fbff);
  padding: 1rem 1.1rem;
}

@media (max-width: 640px) {
  .game-toolbar {
    flex-direction: column;
  }

  .game-scoreboard {
    min-width: 0;
  }

  .game-cell {
    min-height: 84px;
    font-size: 1.65rem;
  }
}

input,
select,
textarea {
  background: rgba(255, 255, 255, 0.85) !important;
  color: var(--brand-ink) !important;
  border-color: rgba(148, 163, 184, 0.26) !important;
}

summary {
  list-style: none;
}

summary::-webkit-details-marker {
  display: none;
}

@media (max-width: 768px) {
  .brand-symbol {
    height: 42px;
    width: 42px;
  }

  .brand-logo-row {
    font-size: 1.35rem;
    gap: 0.16rem;
  }

  .brand-logo-subtitle {
    font-size: 0.58rem;
    letter-spacing: 0.06em;
  }

  .brand-logo {
    height: 42px;
  }

  .brand-logo-lg {
    height: 56px;
  }

  .brand-nav {
    gap: 1rem;
  }

  .brand-dropdown-menu {
    left: auto;
    right: 0;
    min-width: 220px;
  }
}