* { box-sizing: border-box; }

body {
      margin: 0;
      height: 100vh;
      display: flex;
      justify-content: center;
      align-items: center;
      background: #f0f0f0;
      font-family: Arial, sans-serif;
}

.container {
      display: flex;
      gap: 40px;
      align-items: flex-start;
    }

/* =============== BOARD =============== */
#sudoku-board {
      display: grid;
      grid-template-columns: repeat(9, 60px);
      grid-template-rows: repeat(9, 60px);
      background: #000;
      padding: 3px;
      box-shadow: 0 0 10px rgba(0, 0, 0, 0.2);
}

.cell {
      background: #fff;
      display: flex;
      justify-content: center;
      align-items: center;
      font-size: 24px;
      color: #2c3e50;
      outline: none;
      border: none;
}

.prefilled {
      font-weight: bold;
      background: #e9ecef;
}

/* =============== PANEL =============== */
.panel {
      display: flex;
      flex-direction: column;
      gap: 20px;
}

.difficulty, .timer {
      background: #333;
      color: #fff;
      padding: 10px 15px;
      border-radius: 5px;
      font-size: 16px;
}

.btn {
      padding: 10px 20px;
      font-size: 16px;
      border: none;
      border-radius: 6px;
      cursor: pointer;
}

.btn-finish {
      background: #27ae60;
      color: white;
}

.btn-finish:hover {
      background: #1e8449;
}

.exitButton {
    background-color: #ff0000; 
    color: white; 
    padding: 8px 16px; 
    text-decoration: none; 
    border-radius: 4px; 
    border: none; 
    cursor: pointer; 
    display: inline-block; 
    text-align: center;
    transition: background-color 0.3s; 
}

/* Efek saat tombol dihover */
.exitButton:hover {
    background-color: #cc0000; 
}

/* Efek saat tombol ditekan */
.exitButton:active {
    background-color: #990000; 
}

/* =============== MODAL =============== */
.modal {
  display: none;
  position: fixed;
  z-index: 1;
  left: 0;
  top: 0;
  width: 100%;
  height: 100%;
  overflow: auto;
  background-color: rgba(0,0,0,0.4);
}

.modal-content {
  background-color: #fefefe;
  margin: 15% auto;
  padding: 20px;
  border: 1px solid #888;
  width: 80%;
}

.close {
  color: #aaa;
  float: right;
  font-size: 28px;
  font-weight: bold;
}

.close:hover,
.close:focus {
  color: black;
  text-decoration: none;
  cursor: pointer;
}