/* ============================================================
   TIC TAC TOE — NEXUS | style.css
   Neon arcade aesthetic, dark/light themes, fully responsive
   ============================================================ */

/* ---------- CSS Variables ---------- */
:root {
  --bg:         #060611;
  --surface:    #0d0d1f;
  --surface2:   #12122a;
  --border:     rgba(99, 88, 255, 0.25);
  --border-glow:rgba(99, 88, 255, 0.6);
  --x-color:    #ff4d8d;
  --x-glow:     rgba(255, 77, 141, 0.5);
  --o-color:    #00e5ff;
  --o-glow:     rgba(0, 229, 255, 0.5);
  --accent:     #6358ff;
  --accent2:    #a259ff;
  --win-glow:   rgba(255, 220, 50, 0.55);
  --win-color:  #ffdc32;
  --text:       #e8e8f5;
  --text-muted: #7070a0;
  --draw-color: #7070a0;
  --radius:     16px;
  --cell-size:  clamp(90px, 28vw, 130px);
  --font-main:  'Orbitron', sans-serif;
  --font-body:  'Rajdhani', sans-serif;
  --transition: 0.2s ease;
}

[data-theme="light"] {
  --bg:         #f0eeff;
  --surface:    #ffffff;
  --surface2:   #ece9ff;
  --border:     rgba(99, 88, 255, 0.2);
  --border-glow:rgba(99, 88, 255, 0.45);
  --x-color:    #e0005a;
  --x-glow:     rgba(224, 0, 90, 0.25);
  --o-color:    #007acc;
  --o-glow:     rgba(0, 122, 204, 0.25);
  --accent:     #5548e0;
  --accent2:    #8a40e0;
  --win-glow:   rgba(200, 155, 0, 0.3);
  --win-color:  #c89b00;
  --text:       #1a1a3a;
  --text-muted: #7070a0;
  --draw-color: #8888aa;
}

/* ---------- Reset & Base ---------- */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

html { scroll-behavior: smooth; }

body {
  font-family: var(--font-body);
  background: var(--bg);
  color: var(--text);
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  overflow-x: hidden;
  transition: background 0.4s, color 0.4s;
}

/* ---------- Background ---------- */
.bg-grid {
  position: fixed;
  inset: 0;
  background-image:
    linear-gradient(var(--border) 1px, transparent 1px),
    linear-gradient(90deg, var(--border) 1px, transparent 1px);
  background-size: 48px 48px;
  pointer-events: none;
  z-index: 0;
  opacity: 0.5;
}

.bg-glow {
  position: fixed;
  inset: 0;
  background: radial-gradient(ellipse 60% 50% at 50% 30%, rgba(99,88,255,0.12) 0%, transparent 70%);
  pointer-events: none;
  z-index: 0;
}

/* ---------- Container ---------- */
.container {
  position: relative;
  z-index: 1;
  width: min(560px, 96vw);
  padding: 24px 20px 32px;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 20px;
}

/* ---------- Header ---------- */
.header {
  width: 100%;
  display: flex;
  align-items: center;
  justify-content: center;
  position: relative;
}

.logo {
  font-family: var(--font-main);
  font-size: clamp(1.5rem, 6vw, 2.2rem);
  font-weight: 900;
  letter-spacing: 0.1em;
  display: flex;
  gap: 12px;
  align-items: center;
  user-select: none;
}
.logo-x  { color: var(--x-color); text-shadow: 0 0 20px var(--x-glow); }
.logo-o  { color: var(--o-color); text-shadow: 0 0 20px var(--o-glow); }
.logo-title { color: var(--text); }

.theme-toggle {
  position: absolute;
  right: 0;
  background: var(--surface2);
  border: 1px solid var(--border);
  border-radius: 50%;
  width: 40px;
  height: 40px;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.1rem;
  color: var(--text);
  transition: border-color var(--transition), transform var(--transition);
}
.theme-toggle:hover { border-color: var(--accent); transform: rotate(20deg); }

/* ---------- Mode Tabs ---------- */
.mode-tabs {
  display: flex;
  gap: 8px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 50px;
  padding: 5px;
}

.mode-tab {
  font-family: var(--font-main);
  font-size: 0.7rem;
  font-weight: 700;
  letter-spacing: 0.08em;
  display: flex;
  align-items: center;
  gap: 6px;
  padding: 9px 22px;
  border: none;
  border-radius: 50px;
  cursor: pointer;
  background: transparent;
  color: var(--text-muted);
  transition: all 0.25s;
}
.mode-tab .tab-icon { font-size: 1rem; }
.mode-tab.active {
  background: linear-gradient(135deg, var(--accent), var(--accent2));
  color: #fff;
  box-shadow: 0 0 20px rgba(99, 88, 255, 0.45);
}
.mode-tab:not(.active):hover { color: var(--text); }

/* ---------- Difficulty ---------- */
.difficulty-section {
  width: 100%;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 10px;
  opacity: 1;
  transform: translateY(0);
  transition: opacity 0.3s, transform 0.3s;
}
.difficulty-section.hidden {
  opacity: 0;
  pointer-events: none;
  transform: translateY(-10px);
}

.section-label {
  font-family: var(--font-main);
  font-size: 0.6rem;
  letter-spacing: 0.2em;
  color: var(--text-muted);
}

.difficulty-tabs {
  display: flex;
  gap: 8px;
  width: 100%;
}

.diff-btn {
  flex: 1;
  display: flex;
  flex-direction: column;
  align-items: center;
  padding: 12px 8px;
  border-radius: var(--radius);
  border: 1px solid var(--border);
  background: var(--surface);
  cursor: pointer;
  color: var(--text-muted);
  transition: all 0.25s;
}
.diff-btn .diff-name {
  font-family: var(--font-main);
  font-size: 0.65rem;
  font-weight: 700;
  letter-spacing: 0.1em;
}
.diff-btn .diff-desc {
  font-family: var(--font-body);
  font-size: 0.7rem;
  margin-top: 3px;
  opacity: 0.7;
}
.diff-btn.active[data-diff="easy"] {
  border-color: #22ee88;
  background: rgba(34, 238, 136, 0.1);
  color: #22ee88;
  box-shadow: 0 0 18px rgba(34, 238, 136, 0.25);
}
.diff-btn.active[data-diff="medium"] {
  border-color: #ffaa00;
  background: rgba(255, 170, 0, 0.1);
  color: #ffaa00;
  box-shadow: 0 0 18px rgba(255, 170, 0, 0.25);
}
.diff-btn.active[data-diff="hard"] {
  border-color: var(--x-color);
  background: rgba(255, 77, 141, 0.1);
  color: var(--x-color);
  box-shadow: 0 0 18px var(--x-glow);
}
.diff-btn:not(.active):hover { border-color: var(--border-glow); color: var(--text); }

/* ---------- Status ---------- */
.status-section { width: 100%; display: flex; justify-content: center; }

.status-badge {
  display: flex;
  align-items: center;
  gap: 10px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 50px;
  padding: 10px 24px;
  min-width: 200px;
  justify-content: center;
}

.status-dot {
  width: 10px;
  height: 10px;
  border-radius: 50%;
  background: var(--x-color);
  box-shadow: 0 0 10px var(--x-glow);
  transition: background 0.3s, box-shadow 0.3s;
  flex-shrink: 0;
}
.status-dot.o {
  background: var(--o-color);
  box-shadow: 0 0 10px var(--o-glow);
}
.status-dot.draw {
  background: var(--draw-color);
  box-shadow: none;
}

.status-text {
  font-family: var(--font-main);
  font-size: 0.75rem;
  font-weight: 700;
  letter-spacing: 0.08em;
  color: var(--text);
  white-space: nowrap;
}

/* ---------- Board ---------- */
.board-wrapper {
  perspective: 800px;
}

.board {
  display: grid;
  grid-template-columns: repeat(3, var(--cell-size));
  grid-template-rows: repeat(3, var(--cell-size));
  gap: 10px;
  position: relative;
}

/* Grid lines as pseudo-elements on board */
.board::before, .board::after {
  content: '';
  position: absolute;
  background: linear-gradient(90deg, transparent, var(--border-glow), transparent);
  pointer-events: none;
  border-radius: 2px;
}

/* ---------- Cells ---------- */
.cell {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  display: flex;
  align-items: center;
  justify-content: center;
  font-family: var(--font-main);
  font-size: clamp(2.2rem, 9vw, 3.8rem);
  font-weight: 900;
  cursor: pointer;
  position: relative;
  overflow: hidden;
  transition: border-color 0.2s, background 0.2s, transform 0.15s;
  user-select: none;
}

.cell::before {
  content: '';
  position: absolute;
  inset: 0;
  background: radial-gradient(circle at 50% 50%, rgba(99,88,255,0.08), transparent 70%);
  opacity: 0;
  transition: opacity 0.3s;
}
.cell:not(.taken):hover::before { opacity: 1; }
.cell:not(.taken):hover {
  border-color: var(--border-glow);
  transform: translateY(-2px);
  box-shadow: 0 8px 24px rgba(99, 88, 255, 0.15);
}

/* X and O rendering */
.cell.x {
  color: var(--x-color);
  text-shadow: 0 0 18px var(--x-glow), 0 0 40px var(--x-glow);
  border-color: rgba(255, 77, 141, 0.3);
  background: rgba(255, 77, 141, 0.05);
}
.cell.o {
  color: var(--o-color);
  text-shadow: 0 0 18px var(--o-glow), 0 0 40px var(--o-glow);
  border-color: rgba(0, 229, 255, 0.3);
  background: rgba(0, 229, 255, 0.05);
}

/* Place animation */
@keyframes placeX {
  0%   { transform: scale(0) rotate(-20deg); opacity: 0; }
  60%  { transform: scale(1.15) rotate(5deg); opacity: 1; }
  100% { transform: scale(1) rotate(0deg); opacity: 1; }
}
@keyframes placeO {
  0%   { transform: scale(0); opacity: 0; }
  60%  { transform: scale(1.15); opacity: 1; }
  100% { transform: scale(1); opacity: 1; }
}

.cell.x .cell-symbol { display: inline-block; animation: placeX 0.3s cubic-bezier(0.34, 1.56, 0.64, 1) forwards; }
.cell.o .cell-symbol { display: inline-block; animation: placeO 0.3s cubic-bezier(0.34, 1.56, 0.64, 1) forwards; }

/* Winning cells */
.cell.winner {
  border-color: var(--win-color) !important;
  background: rgba(255, 220, 50, 0.12) !important;
  box-shadow: 0 0 20px var(--win-glow), inset 0 0 20px var(--win-glow);
  animation: winPulse 0.8s ease infinite alternate;
}
@keyframes winPulse {
  from { box-shadow: 0 0 16px var(--win-glow), inset 0 0 10px var(--win-glow); }
  to   { box-shadow: 0 0 32px var(--win-glow), inset 0 0 22px var(--win-glow); }
}

/* Disabled board */
.board.disabled .cell { cursor: default; }
.board.disabled .cell:not(.taken):hover {
  border-color: var(--border);
  transform: none;
  box-shadow: none;
}

/* ---------- Scoreboard ---------- */
.scoreboard {
  width: 100%;
  display: grid;
  grid-template-columns: 1fr auto 1fr;
  gap: 8px;
}

.score-item {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 14px 10px;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 4px;
}

.score-symbol {
  font-family: var(--font-main);
  font-size: 1.4rem;
  font-weight: 900;
}
.score-x .score-symbol  { color: var(--x-color); text-shadow: 0 0 12px var(--x-glow); }
.score-o .score-symbol  { color: var(--o-color); text-shadow: 0 0 12px var(--o-glow); }
.score-draw .score-symbol { color: var(--draw-color); }

.score-label {
  font-family: var(--font-main);
  font-size: 0.5rem;
  letter-spacing: 0.12em;
  color: var(--text-muted);
  text-align: center;
}
.score-value {
  font-family: var(--font-main);
  font-size: 1.8rem;
  font-weight: 900;
  color: var(--text);
  transition: transform 0.2s;
}
.score-value.bump {
  animation: scoreBump 0.35s cubic-bezier(0.34, 1.56, 0.64, 1);
}
@keyframes scoreBump {
  0%   { transform: scale(1); }
  50%  { transform: scale(1.35); }
  100% { transform: scale(1); }
}

/* ---------- Controls ---------- */
.controls {
  display: flex;
  gap: 10px;
  width: 100%;
}

.btn-restart, .btn-reset {
  flex: 1;
  font-family: var(--font-main);
  font-size: 0.7rem;
  font-weight: 700;
  letter-spacing: 0.1em;
  padding: 14px;
  border-radius: var(--radius);
  border: 1px solid;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  transition: all 0.2s;
}
.btn-icon { font-size: 1rem; }

.btn-restart {
  background: linear-gradient(135deg, var(--accent), var(--accent2));
  border-color: transparent;
  color: #fff;
  box-shadow: 0 0 20px rgba(99, 88, 255, 0.3);
}
.btn-restart:hover { box-shadow: 0 0 32px rgba(99, 88, 255, 0.6); transform: translateY(-2px); }

.btn-reset {
  background: transparent;
  border-color: var(--border);
  color: var(--text-muted);
}
.btn-reset:hover { border-color: var(--border-glow); color: var(--text); }

/* ---------- Overlay ---------- */
.overlay {
  position: fixed;
  inset: 0;
  background: rgba(6, 6, 17, 0.85);
  backdrop-filter: blur(8px);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 100;
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.35s;
}
.overlay.show {
  opacity: 1;
  pointer-events: all;
}

.overlay-card {
  background: var(--surface);
  border: 1px solid var(--border-glow);
  border-radius: 24px;
  padding: 48px 40px;
  text-align: center;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 14px;
  box-shadow: 0 0 60px rgba(99, 88, 255, 0.3);
  transform: scale(0.85);
  transition: transform 0.35s cubic-bezier(0.34, 1.56, 0.64, 1);
}
.overlay.show .overlay-card { transform: scale(1); }

.overlay-emoji { font-size: 3.5rem; animation: emojiPop 0.5s ease; }
@keyframes emojiPop {
  0%   { transform: scale(0) rotate(-30deg); }
  70%  { transform: scale(1.2) rotate(5deg); }
  100% { transform: scale(1); }
}

.overlay-title {
  font-family: var(--font-main);
  font-size: clamp(1.4rem, 5vw, 2rem);
  font-weight: 900;
  letter-spacing: 0.1em;
  color: var(--text);
}

.overlay-sub {
  font-family: var(--font-body);
  font-size: 1rem;
  color: var(--text-muted);
  letter-spacing: 0.05em;
}

.btn-play-again {
  margin-top: 10px;
  font-family: var(--font-main);
  font-size: 0.75rem;
  font-weight: 700;
  letter-spacing: 0.12em;
  padding: 14px 36px;
  border-radius: 50px;
  border: none;
  background: linear-gradient(135deg, var(--accent), var(--accent2));
  color: #fff;
  cursor: pointer;
  box-shadow: 0 0 24px rgba(99, 88, 255, 0.4);
  transition: all 0.2s;
}
.btn-play-again:hover { box-shadow: 0 0 40px rgba(99, 88, 255, 0.7); transform: translateY(-2px); }

/* ---------- AI Thinking indicator ---------- */
.thinking-dots {
  display: inline-flex;
  gap: 4px;
  align-items: center;
  margin-left: 8px;
}
.thinking-dots span {
  width: 5px;
  height: 5px;
  background: var(--o-color);
  border-radius: 50%;
  animation: dotBounce 0.8s ease infinite;
}
.thinking-dots span:nth-child(2) { animation-delay: 0.15s; }
.thinking-dots span:nth-child(3) { animation-delay: 0.3s; }
@keyframes dotBounce {
  0%, 100% { transform: translateY(0); opacity: 0.5; }
  50%       { transform: translateY(-5px); opacity: 1; }
}

/* ---------- Responsive ---------- */
@media (max-width: 420px) {
  .container { padding: 16px 12px 24px; gap: 14px; }
  .diff-btn .diff-desc { display: none; }
  .diff-btn { padding: 10px 4px; }
  .scoreboard { gap: 6px; }
  .overlay-card { padding: 36px 24px; }
}