:root {
  --bg: #0a1018;
  --text: #f3f7ff;
  --muted: #a9b7d2;
  --panel: rgba(26, 38, 56, 0.88);
  --panel-2: rgba(18, 28, 43, 0.9);
  --border: rgba(162, 193, 238, 0.24);
  --accent: #4fdcff;
  --accent-2: #7bffb3;
  --shadow: 0 16px 36px rgba(0, 0, 0, 0.36);
  --max-width: 1120px;
  --icon-cyan: #7deaff;
  --icon-blue: #85b5ff;
  --icon-violet: #db79ff;
  --icon-gold: #ffd86a;
  --icon-soft-outline: rgba(173, 223, 255, 0.36);
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  color: var(--text);
  font-family: "Avenir Next", "Segoe UI", sans-serif;
  line-height: 1.5;
  background:
    radial-gradient(circle at 16% 14%, rgba(79, 220, 255, 0.12), transparent 38%),
    radial-gradient(circle at 84% 10%, rgba(123, 255, 179, 0.09), transparent 42%),
    linear-gradient(180deg, #0a1018 0%, #0d1523 62%, #0a1018 100%);
}

.container {
  width: min(calc(100% - 32px), var(--max-width));
  margin: 0 auto;
}

.site-header {
  position: sticky;
  top: 0;
  z-index: 120;
  border-bottom: 1px solid rgba(162, 193, 238, 0.2);
  background: rgba(10, 16, 24, 0.88);
  backdrop-filter: blur(8px);
}

.header-inner {
  min-height: 64px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 14px;
}

.brand {
  display: inline-flex;
  align-items: center;
  flex: 0 0 auto;
  color: var(--text);
  text-decoration: none;
}

.site-logo {
  display: block;
  width: auto;
  height: 34px;
  max-width: min(44vw, 176px);
}

.visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

.header-nav {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

.header-nav a {
  color: #d6e4fb;
  text-decoration: none;
  font-size: 0.93rem;
  font-weight: 600;
}

.header-nav a:hover,
.header-nav a:focus-visible {
  color: white;
}

.uiIcon {
  width: 20px;
  height: 20px;
  display: inline-block;
  flex: 0 0 auto;
  stroke: currentColor;
  fill: none;
  overflow: visible;
  color: var(--icon-cyan);
  filter:
    drop-shadow(0 0 1px rgba(255, 255, 255, 0.55))
    drop-shadow(0 0 6px rgba(83, 203, 255, 0.42))
    drop-shadow(0 0 12px rgba(162, 110, 255, 0.22));
  transition: transform 0.16s ease, filter 0.16s ease, color 0.16s ease;
}

.uiIcon--sm {
  width: 18px;
  height: 18px;
}

.uiIcon--lg {
  width: 24px;
  height: 24px;
}

.iconLabel {
  display: inline-flex;
  align-items: center;
  gap: 8px;
}

.iconButton {
  display: inline-flex;
  align-items: center;
  gap: 8px;
}

.iconCardTitle {
  display: inline-flex;
  align-items: center;
  gap: 8px;
}

.iconLabel .uiIcon,
.iconButton .uiIcon {
  color: var(--icon-cyan);
}

.iconButton .uiIcon,
.iconCardTitle .uiIcon {
  padding: 2px;
  border-radius: 0;
  background: linear-gradient(165deg, rgba(110, 196, 255, 0.2), rgba(199, 106, 255, 0.14));
  box-shadow:
    inset 0 1px 0 rgba(255, 255, 255, 0.24),
    0 0 0 1px var(--icon-soft-outline),
    0 0 12px rgba(83, 203, 255, 0.22);
}

.site-header .iconLabel .uiIcon {
  color: var(--icon-blue);
}

.daily-copy h1 .uiIcon,
#theme-title .uiIcon,
#related-title .uiIcon,
.tray h2 .uiIcon {
  color: var(--icon-gold);
  filter:
    drop-shadow(0 0 1px rgba(255, 250, 226, 0.6))
    drop-shadow(0 0 7px rgba(255, 204, 89, 0.48))
    drop-shadow(0 0 13px rgba(219, 121, 255, 0.23));
}

#restart-btn .uiIcon {
  color: var(--icon-gold);
}

#sound-btn .uiIcon {
  color: var(--icon-blue);
}

a:hover .uiIcon,
button:hover .uiIcon,
a:focus-visible .uiIcon,
button:focus-visible .uiIcon {
  transform: translateY(-1px) scale(1.06);
  filter:
    drop-shadow(0 0 1px rgba(255, 255, 255, 0.65))
    drop-shadow(0 0 8px rgba(90, 213, 255, 0.56))
    drop-shadow(0 0 16px rgba(182, 104, 255, 0.34));
}

@media (prefers-reduced-motion: reduce) {
  .uiIcon {
    transition: none;
  }

  a:hover .uiIcon,
  button:hover .uiIcon,
  a:focus-visible .uiIcon,
  button:focus-visible .uiIcon {
    transform: none;
  }
}

main {
  padding: 30px 0 54px;
}

.daily-layout {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(340px, 520px);
  align-items: start;
  gap: 28px;
}

.daily-copy {
  border: 1px solid var(--border);
  border-radius: 16px;
  background: var(--panel-2);
  padding: 18px;
}

.daily-copy h1 {
  margin: 0;
  font-size: clamp(1.8rem, 3.5vw, 2.6rem);
}

.lead {
  margin: 12px 0 0;
  color: #cfdbf1;
}

.daily-meta {
  margin-top: 12px;
  color: var(--muted);
  font-size: 0.92rem;
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

.info-card {
  margin-top: 14px;
  border: 1px solid var(--border);
  border-radius: 12px;
  background: rgba(22, 34, 50, 0.8);
  padding: 12px;
}

.info-card h2,
.info-card h3 {
  margin: 0 0 8px;
  font-size: 1.02rem;
}

.info-card p,
.info-card li {
  color: #d3e0f4;
}

.info-card ul,
.info-card ol {
  margin: 8px 0 0;
  padding-left: 20px;
}

.solution-toggle {
  border: 1px solid rgba(142, 203, 255, 0.42);
  border-radius: 10px;
  padding: 8px 12px;
  color: #dcf0ff;
  background: rgba(57, 104, 143, 0.3);
  cursor: pointer;
  font-weight: 650;
}

.solution-toggle:hover {
  background: rgba(67, 122, 166, 0.36);
}

.hidden {
  display: none !important;
}

.game-shell {
  border: 1px solid rgba(174, 208, 255, 0.28);
  border-radius: 22px;
  background: linear-gradient(180deg, rgba(30, 42, 60, 0.92), rgba(23, 33, 48, 0.9));
  box-shadow: var(--shadow);
  padding: 14px;
}

.hud {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 8px;
  margin-bottom: 10px;
}

.hud-item {
  border: 1px solid var(--border);
  border-radius: 10px;
  background: rgba(17, 28, 43, 0.84);
  padding: 8px;
}

.hud-item span {
  display: block;
  color: var(--muted);
  font-size: 0.76rem;
}

.hud-item strong {
  font-size: 1rem;
}

.control-row {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-bottom: 10px;
}

.control-row button,
.control-row select {
  min-height: 38px;
  border-radius: 9px;
  border: 1px solid var(--border);
  background: rgba(18, 32, 48, 0.9);
  color: var(--text);
  font-weight: 620;
  padding: 0 10px;
}

#board {
  width: 100%;
  aspect-ratio: 1;
  display: grid;
  grid-template-columns: repeat(9, minmax(0, 1fr));
  grid-template-rows: repeat(9, minmax(0, 1fr));
  gap: 3px;
  touch-action: none;
  transition: box-shadow 140ms ease;
}

#board.focus {
  box-shadow: 0 0 18px rgba(79, 220, 255, 0.42);
}

#board.shake {
  animation: boardShake 220ms ease;
}

@keyframes boardShake {
  0%,
  100% {
    transform: translateX(0);
  }
  25% {
    transform: translateX(-3px);
  }
  75% {
    transform: translateX(3px);
  }
}

.board-cell {
  position: relative;
  background: rgba(255, 255, 255, 0.08);
  border: 1px solid rgba(255, 255, 255, 0.18);
  border-radius: 10px;
  box-shadow:
    0 1px 0 rgba(255, 255, 255, 0.18) inset,
    0 -6px 10px rgba(0, 0, 0, 0.1) inset;
}

.board-cell.filled {
  background: linear-gradient(180deg, var(--top), var(--bottom));
  border-color: rgba(255, 255, 255, 0.34);
  box-shadow:
    0 0 12px var(--glow),
    0 1px 0 rgba(255, 255, 255, 0.3) inset,
    0 -8px 11px rgba(0, 0, 0, 0.18) inset;
}

.board-cell.filled::before {
  content: "";
  position: absolute;
  inset: 2px 3px auto 3px;
  height: 34%;
  border-radius: 8px;
  background: linear-gradient(180deg, rgba(255, 255, 255, 0.45), rgba(255, 255, 255, 0));
}

.board-cell.preview-valid {
  border-color: rgba(123, 197, 255, 0.75);
  background: rgba(93, 179, 255, 0.28);
  box-shadow:
    0 0 0 2px rgba(93, 179, 255, 0.5) inset,
    0 0 14px rgba(93, 179, 255, 0.32);
}

.board-cell.preview-invalid {
  border-color: rgba(255, 131, 152, 0.75);
  background: rgba(255, 108, 136, 0.26);
  box-shadow:
    0 0 0 2px rgba(255, 108, 136, 0.6) inset,
    0 0 14px rgba(255, 108, 136, 0.32);
}

.board-cell.preview-valid::after,
.board-cell.preview-invalid::after {
  content: "";
  position: absolute;
  inset: 2px;
  border-radius: 8px;
  pointer-events: none;
}

.board-cell.preview-valid::after {
  background: linear-gradient(180deg, rgba(198, 229, 255, 0.45), rgba(93, 179, 255, 0.08));
}

.board-cell.preview-invalid::after {
  background: linear-gradient(180deg, rgba(255, 214, 221, 0.44), rgba(255, 108, 136, 0.08));
}

.color-i {
  --top: #7ceaff;
  --bottom: #2db9e6;
  --glow: rgba(68, 216, 255, 0.22);
}

.color-o {
  --top: #ffe894;
  --bottom: #d0aa2a;
  --glow: rgba(247, 215, 90, 0.22);
}

.color-t {
  --top: #d2b0ff;
  --bottom: #8f63da;
  --glow: rgba(184, 137, 255, 0.22);
}

.color-s {
  --top: #90ffb7;
  --bottom: #3dcf76;
  --glow: rgba(77, 242, 139, 0.22);
}

.color-z {
  --top: #ff9ab0;
  --bottom: #de4b68;
  --glow: rgba(255, 106, 132, 0.22);
}

.color-j {
  --top: #95b4ff;
  --bottom: #3f6fd9;
  --glow: rgba(90, 141, 255, 0.22);
}

.color-l {
  --top: #ffd196;
  --bottom: #da8f34;
  --glow: rgba(255, 179, 91, 0.22);
}

.tray {
  margin-top: 10px;
  border: 1px solid var(--border);
  border-radius: 14px;
  background: rgba(255, 255, 255, 0.06);
  padding: 10px;
}

.tray h2 {
  margin: 0 0 8px;
  font-size: 0.96rem;
}

.tray-list {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 8px;
}

.tray-piece {
  width: 100%;
  border-radius: 12px;
  border: 1px solid rgba(190, 214, 252, 0.24);
  background: rgba(11, 19, 31, 0.6);
  padding: 5px;
  cursor: grab;
  touch-action: none;
  user-select: none;
  -webkit-user-select: none;
}

.tray-piece.selected {
  border-color: rgba(123, 255, 179, 0.75);
  box-shadow: 0 0 0 2px rgba(123, 255, 179, 0.22) inset;
}

.tray-piece.empty {
  opacity: 0.45;
}

.preview-grid {
  display: grid;
  grid-template-columns: repeat(5, minmax(0, 1fr));
  grid-template-rows: repeat(5, minmax(0, 1fr));
  gap: 2px;
  aspect-ratio: 1;
}

.preview-cell {
  border-radius: 7px;
  border: 1px solid rgba(255, 255, 255, 0.18);
  background: rgba(255, 255, 255, 0.08);
}

.preview-cell.filled {
  background: linear-gradient(180deg, var(--top), var(--bottom));
  border-color: rgba(255, 255, 255, 0.34);
  box-shadow: 0 0 8px var(--glow);
}

.game-over {
  margin-top: 10px;
  padding: 10px;
  border-radius: 10px;
  border: 1px solid rgba(255, 125, 146, 0.4);
  background: rgba(102, 26, 42, 0.45);
}

.nav-links,
.related-links {
  margin-top: 12px;
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

.nav-links a,
.related-links a,
.archive-month a {
  color: #d8e9ff;
  text-decoration: none;
  border: 1px solid rgba(160, 198, 255, 0.28);
  border-radius: 9px;
  padding: 7px 10px;
  background: rgba(24, 35, 52, 0.72);
  font-size: 0.9rem;
}

.nav-links a:hover,
.related-links a:hover,
.archive-month a:hover {
  color: white;
  border-color: rgba(123, 255, 179, 0.56);
}

.archive-wrap {
  border: 1px solid var(--border);
  border-radius: 16px;
  background: var(--panel);
  padding: 14px;
}

.archive-wrap h1 {
  margin-top: 0;
  font-size: clamp(1.8rem, 3.8vw, 2.4rem);
}

.archive-grid {
  margin-top: 14px;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 12px;
}

.archive-month {
  border: 1px solid rgba(165, 193, 236, 0.28);
  border-radius: 12px;
  padding: 10px;
  background: rgba(15, 27, 43, 0.72);
}

.archive-month h2 {
  margin: 0 0 8px;
  font-size: 1.04rem;
}

.archive-days {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
}

footer {
  margin-top: 40px;
  color: var(--muted);
  text-align: center;
  font-size: 0.9rem;
}

@media (max-width: 900px) {
  .daily-layout {
    grid-template-columns: 1fr;
  }

  .game-shell {
    max-width: 520px;
    margin: 0 auto;
  }

  .archive-grid {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 430px) {
  .container {
    width: min(calc(100% - 20px), var(--max-width));
  }

  .header-inner {
    min-height: 56px;
  }

  .brand .site-logo {
    height: 30px;
  }

  .header-nav {
    gap: 8px;
    font-size: 0.82rem;
  }

  .daily-copy {
    padding: 14px;
  }

  .daily-copy h1 {
    font-size: clamp(1.5rem, 7.6vw, 2rem);
  }

  .lead {
    font-size: 0.94rem;
  }

  .hud {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .tray {
    padding: 8px;
  }

  .tray-list {
    gap: 6px;
  }
}