/* ===========================================
   Simple Calculator - Tool Specific Styles
   =========================================== */

/* Tool Layout */
.cal-box {
    max-width: 300px; /* Smaller footprint than scientific */
    margin: 0 auto;
    background: #ffffff;
    border-radius: 15px;
    box-shadow: 0 10px 20px rgba(0, 0, 0, 0.1);
    padding: 20px;
}

/* Display Area */
.cal-display-area {
    margin-bottom: 15px;
    background: #f0f4f8; /* Light Blueish Gray */
    border-radius: 8px;
    padding: 10px;
    border: 1px solid #c9d7e5;
}

.cal-history {
    font-size: 0.8rem;
    color: #607289;
    min-height: 16px;
    text-align: right;
    overflow: hidden;
    white-space: nowrap;
}

.cal-input {
    width: 100%;
    font-size: 2rem;
    font-weight: 700;
    color: #1f2937;
    text-align: right;
    border: none;
    background: transparent;
    padding: 0;
    margin: 0;
    outline: none; 
}

/* Keypad Grid */
.cal-keypad {
    display: grid;
    grid-template-columns: repeat(4, 1fr); /* 4 standard columns */
    gap: 10px;
}

/* Buttons */
.cal-btn {
    padding: 15px 5px;
    font-size: 1.2rem;
    font-weight: 600;
    border: none;
    border-radius: 8px;
    cursor: pointer;
    transition: background 0.15s, transform 0.05s;
    height: 60px;
    display: flex;
    align-items: center;
    justify-content: center;
    color: #1f2937;
}

.cal-btn:active {
    transform: scale(0.98);
}

/* Operation Buttons (+, -, x, /) - Primary Blue */
.btn-operation {
    background: #dbeafe; 
    color: #3b82f6;
}
.btn-operation:hover {
    background: #bfdbfe;
}

/* Control Buttons (AC, C) - Red */
.btn-control {
    background: #fee2e2;
    color: #ef4444;
}
.btn-control:hover {
    background: #fecaca;
}

/* Equals Button (=) - Darker Blue/Full Column */
.btn-equals {
    background: #3b82f6; 
    color: white;
    font-size: 1.5rem;
}
.btn-equals:hover {
    background: #2563eb;
}

/* Number/Decimal Buttons - Standard Grey */
.btn-number {
    background: #f3f4f6;
    color: #1f2937;
}
.btn-number:hover {
    background: #e5e7eb;
}

/* Zero button spanning two columns */
.btn-zero {
    grid-column: span 2;
}