:root { --bg: #1a1a1a; --text: #4caf50; }
* { box-sizing: border-box; margin: 0; padding: 0; }
body { font-family: 'Outfit', sans-serif; background: var(--bg); color: var(--text); min-height: 100vh; display: flex;
    flex-direction: column; justify-content: flex-start; align-items: center; }
.game-container { width: 100%; max-width: 400px; padding: 1rem; display: flex; flex-direction: column; align-items: center; position: relative;}
header { width: 100%; display: flex; justify-content: space-between; align-items: center; margin-bottom: 1rem; }
.back-btn { text-decoration: none; background: #4caf50; color: white; padding: 10px 20px; border-radius: 20px; font-weight: bold; box-shadow: 0 4px 0 #388e3c; }
.back-btn:active { transform: translateY(4px); box-shadow: 0 0 0; }
h1 { font-size: 2rem; color: #4caf50; text-shadow: 2px 2px 0 #000; }
.instruction { font-size: 1.5rem; margin-bottom: 2rem; font-weight: bold; text-align: center;}
.highlight { color: #ff5722; font-size: 2rem; background: #2a2a2a; padding: 5px 15px; border-radius: 10px; border: 2px dashed #ff5722; display: inline-block; margin-top: 10px;}

.grid { display: grid; grid-template-columns: repeat(4, 60px); grid-template-rows: repeat(4, 60px); gap: 10px; background: #2a2a2a; padding: 15px; border-radius: 15px; box-shadow: 0 10px 30px rgba(0,0,0,0.1); }
.cell { background: #c8e6c9; border-radius: 10px; display: flex; justify-content: center; align-items: center; font-size: 2.5rem; font-weight: bold; color: #1b5e20; cursor: pointer; user-select: none; transition: transform 0.1s, background 0.2s;}
.cell:active { transform: scale(0.9); }
.cell.selected { background: #ffeb3b; color: #e65100; transform: scale(1.1); box-shadow: 0 5px 15px rgba(255,235,59,0.5);}
.cell.found { background: #4caf50; color: white; transform: scale(1); }

.overlay { position: absolute; inset: 0; background: rgba(30,30,30,0.95); display: flex; flex-direction: column; justify-content: center; align-items: center; z-index: 10; border-radius: 20px; }
.overlay h2 { font-size: 3rem; color: #ff9800; margin-bottom: 1rem; text-align: center;}
.btn { background: #ff9800; border: none; padding: 15px 40px; font-size: 1.5rem; font-weight: 900; border-radius: 50px; cursor: pointer; color: white; font-family: 'Outfit'; box-shadow: 0 5px 0 #f57c00; }
.btn:active { transform: translateY(5px); box-shadow: none; }
.hidden { display: none !important; }