/* Cell core styling */
.cell {
    width: 100%; height: 100%; position: relative;
    outline: none; transition: background-color 0.1s; border: 1px solid #cbd5e1;
    cursor: pointer; user-select: none;
}

/* Clean outline selection (fixes gradient issues) */
.cell.selected {
    box-shadow: inset 0 0 0 4px #3b82f6 !important;
}
.cell.conflict .digit { color: #dc2626 !important; }

/* Mark Layers */
.digit {
    position: absolute; inset: 0; display: flex; justify-content: center; align-items: center;
    /* Responsive font sizing */
    font-size: clamp(1.2rem, 4vw, 2.25rem); 
    font-weight: bold; color: #2563eb; line-height: 1; pointer-events: none;
}
.cell.given .digit { color: #000; }

.center-marks {
    position: absolute; inset: 0; display: flex; justify-content: center; align-items: center; flex-wrap: wrap;
    /* Responsive font sizing */
    font-size: clamp(0.5rem, 1.5vw, 0.8rem); 
    font-weight: 600; color: #4b5563; pointer-events: none; letter-spacing: 1px;
}

.corner-marks {
    position: absolute; inset: 2px; display: grid; grid-template-columns: repeat(3, 1fr); grid-template-rows: repeat(3, 1fr);
    /* Responsive font sizing */
    font-size: clamp(0.4rem, 1.2vw, 0.7rem); 
    font-weight: 600; color: #4b5563; pointer-events: none; line-height: 1; text-align: center;
}

/* Thicker Box Borders - Disabled because SVG handles them perfectly centered */
.box-right { /* border-right: 2px solid #000; */ }
.box-bottom { /* border-bottom: 2px solid #000; */ }
.box-top { /* border-top: 2px solid #000; */ }
.box-left { /* border-left: 2px solid #000; */ }

/* Region Background Colors */
.bg-color-R { background-color: #fee2e2; }
.bg-color-G { background-color: #ecfccb; }
.bg-color-B { background-color: #e0f2fe; }

.bg-color-RG { background: repeating-linear-gradient(45deg, #fee2e2, #fee2e2 10px, #ecfccb 10px, #ecfccb 20px); }
.bg-color-RB { background: repeating-linear-gradient(45deg, #fee2e2, #fee2e2 10px, #e0f2fe 10px, #e0f2fe 20px); }

/* Yaku Labels */
.yaku-label { transition: color 0.3s; }
.label-valid { color: #16a34a !important; text-decoration: line-through; }
.label-invalid { color: #dc2626 !important; }

.label-R { color: #b30000; }
.label-G { color: #009900; }
.label-B { color: #0000b3; }

/* Pause State */
.board-paused {
    filter: blur(6px);
    pointer-events: none;
    user-select: none;
}