/* Default (Dark) Theme Variables */
:root {
    --glow-color: rgb(0, 255, 255);
    --glow-spread-color: rgba(0, 255, 255, 0.4);
    --enhanced-glow-color: rgb(0, 255, 255);
    --btn-color: rgb(20, 20, 20);
    --bg-color: rgb(0, 0, 0);
    --text-color: rgb(255, 255, 255);
    --x-color: rgb(255, 50, 50);
    --o-color: rgb(50, 255, 255);
  }
    
  body {
    background: var(--bg-color);
    color: var(--text-color);
    font-family: 'Roboto', sans-serif;
    text-align: center;
    min-height: 100vh;
    margin: 0;
    padding: 0;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    transition: all 0.5s ease;
    line-height: 1.6;
  }
    
  h1 {
    font-family: 'Montserrat', sans-serif;
    font-size: 4.5vmax;
    margin: 0.5em 0;
    text-shadow: 0 0 0.3em var(--glow-color), 0 0 0.6em var(--glow-color);
    letter-spacing: 2px;
    text-transform: uppercase;
    font-weight: 700;
    transition: text-shadow 0.5s ease;
  }
    
  .player-info {
    margin-bottom: 2vmin;
    font-size: 3vmin;
    text-shadow: 0 0 0.5em var(--glow-color);
    transition: text-shadow 0.5s ease;
    font-family: 'Montserrat', sans-serif;
  }
    
  .current-player {
    font-weight: bold;
    animation: pulseText 1.5s infinite alternate;
  }
    
  @keyframes pulseText {
    0% { 
      opacity: 0.8; 
      text-shadow: 0 0 0.3em currentColor;
    }
    100% { 
      opacity: 1; 
      text-shadow: 0 0 1em currentColor, 0 0 0.5em currentColor;
    }
  }
    
  .game-container {
    display: flex;
    flex-direction: column;
    align-items: center;
    margin-top: 20px;
  }
    
  .board {
    display: grid;
    grid-template-columns: repeat(3, 20vmin);
    grid-template-rows: repeat(3, 20vmin);
    gap: 1.5vmin;
    margin: 2vmin 0;
  }
    
  .cell {
    width: 20vmin;
    height: 20vmin;
    background: rgba(20, 20, 20, 0.2);
    border: 0.25vmin solid var(--glow-color);
    box-shadow: 0 0 0.8em 0.1em var(--glow-spread-color);
    font-size: 8vmin;
    font-weight: bold;
    color: var(--text-color);
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    position: relative;
    transition: all 0.3s;
    border-radius: 0.6em;
    overflow: hidden;
    z-index: 1;
  }
    
  .cell:hover {
    background: rgba(20, 20, 20, 0.4);
    box-shadow: 0 0 1.2em 0.2em var(--glow-spread-color);
  }
    
  .cell.x::before,
  .cell.x::after {
    content: '';
    position: absolute;
    width: 10%;
    height: 70%;
    background-color: var(--x-color);
    border-radius: 1vmin;
    box-shadow: 0 0 1em 0.2em var(--x-color);
    transition: background-color 0.5s ease, box-shadow 0.5s ease;
    z-index: 2;
  }
    
  .cell.x::before {
    transform: rotate(45deg);
  }
    
  .cell.x::after {
    transform: rotate(-45deg);
  }
    
  .cell.o::before {
    content: '';
    position: absolute;
    width: 60%;
    height: 60%;
    border: 0.8vmin solid var(--o-color);
    border-radius: 50%;
    box-shadow: 0 0 1em 0.2em var(--o-color);
    transition: border-color 0.5s ease, box-shadow 0.5s ease;
    z-index: 2;
  }
    
  .win-line {
    position: absolute;
    inset: 0;
    background: rgba(255, 255, 255, 0.2);
    border: 3px solid var(--enhanced-glow-color);
    border-radius: inherit;
    z-index: 0;
    pointer-events: none;
    opacity: 0;
    animation: winPulse 1.5s infinite ease-in-out;
  }
    
  @keyframes winPulse {
    0% { opacity: 0; }
    50% { opacity: 1; }
    100% { opacity: 0; }
  }
    
  button {
    background-color: var(--btn-color);
    color: var(--text-color);
    border: none;
    border-radius: 0.5em;
    padding: 1.5vmin 3vmin;
    margin: 1.5vmin;
    font-size: 2.5vmin;
    font-weight: bold;
    cursor: pointer;
    transition: background-color 0.3s ease, transform 0.2s ease, box-shadow 0.3s ease;
    box-shadow: 0 0 0.5em 0.1em var(--glow-spread-color);
    font-family: 'Montserrat', sans-serif;
  }
    
  button:hover {
    background-color: var(--glow-color);
    transform: scale(1.05);
    box-shadow: 0 0 1em 0.2em var(--glow-spread-color);
  }
    
  button:active {
    transform: scale(0.95);
  }
    
  .player-setup {
    display: flex;
    flex-direction: column;
    align-items: center;
    margin-bottom: 20px;
    width: 80%;
    max-width: 400px;
    font-family: 'Roboto', sans-serif;
  }
    
  .player-setup input {
    padding: 2vmin;
    margin: 1vmin 0;
    width: 100%;
    border-radius: 10px;
    border: 1px solid var(--glow-color);
    background-color: rgba(20, 20, 20, 0.2);
    color: var(--text-color);
    outline: none;
    font-size: 2.5vmin;
    box-shadow: 0 0 0.3em 0.05em var(--glow-spread-color);
    transition: border-color 0.5s ease, box-shadow 0.5s ease, background-color 0.5s ease;
  }
    
  .player-setup input:focus {
    box-shadow: 0 0 0.8em 0.15em var(--glow-color);
  }
    
  .player-setup h2 {
    margin-bottom: 15px;
    font-size: 3vmin;
    text-shadow: 0 0 0.5em var(--glow-color);
    transition: text-shadow 0.5s ease;
    font-family: 'Montserrat', sans-serif;
  }
    
  @media (max-width: 600px) {
    h1 {
      font-size: 6vmax;
      margin: 0.3em 0;
    }
    .board {
      grid-template-columns: repeat(3, 25vmin);
      grid-template-rows: repeat(3, 25vmin);
      gap: 2vmin;
    }
    .cell {
      width: 25vmin;
      height: 25vmin;
      font-size: 10vmin;
    }
    button {
      padding: 3vmin 6vmin;
      font-size: 3.5vmin;
      width: 80%;
      max-width: 300px;
    }
    .player-info {
      font-size: 4vmin;
    }
    .player-setup {
      width: 90%;
    }
    .player-setup input {
      font-size: 4vmin;
      padding: 3vmin;
    }
    .player-setup h2 {
      font-size: 4vmin;
    }
  }
    
  @media (max-width: 400px) {
    .board {
      grid-template-columns: repeat(3, 28vmin);
      grid-template-rows: repeat(3, 28vmin);
    }
    .cell {
      width: 28vmin;
      height: 28vmin;
    }
  }
  
  /* Modal styling matching the theme */
  .modal {
    display: none; 
    position: fixed;
    z-index: 1000;
    left: 0;
    top: 0;
    width: 100%;
    height: 100%;
    overflow: auto;
    background-color: rgba(0,0,0,0.7);
  }
  .modal-content {
    background-color: var(--bg-color);
    color: var(--text-color);
    margin: 15% auto;
    padding: 20px;
    border: 1px solid var(--glow-color);
    width: 80%;
    max-width: 400px;
    text-align: center;
    border-radius: 10px;
    box-shadow: 0 0 1em var(--glow-color);
  }
  .modal-close {
    float: right;
    font-size: 28px;
    font-weight: bold;
    cursor: pointer;
  }
  
  /* More prominent pulsing overlay for move removal */
  .pulse-overlay {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(255,255,255,0.2);
    border-radius: inherit;
    pointer-events: none;
    z-index: 3;
    animation: overlayPulse 2s infinite ease-in-out;
  }
  @keyframes overlayPulse {
    0% { opacity: 0.2; }
    50% { opacity: 0.8; }
    100% { opacity: 0.2; }
  }