:root {
    --primary: #4f46e5;
    --sec: #06b6d4;
    --bg: #f8fafc;
    --card: #ffffff;
}

body {
    font-family: 'Segoe UI', sans-serif;
    background: var(--bg);
    color: #334155;
    padding: 20px;
    display: flex;
    flex-direction: column;
    align-items: center;
}

h1 {
    color: var(--primary);
    margin-bottom: 10px;
}

p {
    font-size: 14px;
    color: #64748b;
    margin-bottom: 20px;
}

/* Controls */
.controls {
    background: var(--card);
    padding: 20px;
    border-radius: 12px;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.05);
    display: flex;
    gap: 15px;
    flex-wrap: wrap;
    justify-content: center;
    margin-bottom: 20px;
}

.input-group {
    display: flex;
    flex-direction: column;
    font-size: 12px;
    font-weight: bold;
}

input,
select {
    padding: 8px;
    border: 1px solid #cbd5e1;
    border-radius: 6px;
    margin-top: 5px;
    width: 80px;
}

button {
    margin-top: auto;
    padding: 10px 20px;
    background: var(--primary);
    color: white;
    border: none;
    border-radius: 6px;
    cursor: pointer;
    font-weight: bold;
    transition: 0.2s;
}

button:hover {
    background: #4338ca;
    transform: translateY(-2px);
}

/* Main Layout */
.main-area {
    display: flex;
    gap: 20px;
    flex-wrap: wrap;
    justify-content: center;
    width: 100%;
    max-width: 1000px;
}

/* Grid Section */
.grid-section {
    flex: 1;
    background: var(--card);
    padding: 20px;
    border-radius: 12px;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.05);
    min-width: 300px;
    display: flex;
    justify-content: center;
    align-items: flex-start;
}

.grid {
    display: grid;
    gap: 8px;
}

.cell {
    width: 60px;
    height: 60px;
    background: #e2e8f0;
    border-radius: 8px;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    transition: 0.2s;
    border: 2px solid transparent;
    font-size: 12px;
}

.cell:hover {
    border-color: var(--sec);
    transform: scale(1.05);
}

.cell.active {
    background: var(--primary);
    color: white;
    border-color: var(--primary);
    box-shadow: 0 0 10px rgba(79, 70, 229, 0.4);
}

.cell span {
    font-size: 10px;
    opacity: 0.7;
}

/* Formula Panel */
.formula-panel {
    flex: 1;
    background: #1e293b;
    color: #f1f5f9;
    padding: 25px;
    border-radius: 12px;
    min-width: 300px;
    box-shadow: 0 10px 15px -3px rgba(0, 0, 0, 0.1);
}

.formula-title {
    text-transform: uppercase;
    letter-spacing: 1px;
    font-size: 12px;
    color: #94a3b8;
    margin-bottom: 10px;
    border-bottom: 1px solid #334155;
    padding-bottom: 5px;
}

.big-math {
    font-family: 'Courier New', monospace;
    font-size: 18px;
    margin: 15px 0;
    line-height: 1.6;
}

.highlight {
    color: #22d3ee;
    font-weight: bold;
}

/* Cyan for dynamic numbers */
.var-i {
    color: #f472b6;
}

/* Pink for Row */
.var-j {
    color: #a78bfa;
}

/* Purple for Col */
.result-box {
    background: var(--primary);
    padding: 10px;
    border-radius: 6px;
    text-align: center;
    font-weight: bold;
    margin-top: 20px;
    font-size: 20px;
}