/* GLOBAL RESET */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    background-color: #e0f7fa; /* Light Blue background */
    font-family: 'Poppins', sans-serif;
    color: #333;
    display: flex;
    justify-content: center;
    min-height: 100vh;
    padding: 20px;
}

.main-wrapper {
    width: 100%;
    max-width: 500px;
    display: flex;
    flex-direction: column;
    gap: 40px;
}

h1 {
    text-align: center;
    color: #2f3640;
    margin-bottom: 15px;
    font-weight: 600;
    letter-spacing: 1px;
}

/* --- COMMON CONTAINER STYLES --- */
.program-container {
    animation: fadeIn 0.8s ease-in-out;
}

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(20px); }
    to { opacity: 1; transform: translateY(0); }
}

/* --- CALCULATOR STYLES --- */
.calculator-box {
    background-color: #2f3640; /* Dark Slate */
    border-radius: 20px;
    padding: 25px;
    box-shadow: 0px 15px 25px rgba(0,0,0,0.2);
}

.display-container input {
    width: 100%;
    height: 70px;
    background-color: #ecf0f1;
    border: none;
    border-radius: 10px;
    margin-bottom: 20px;
    text-align: right;
    font-size: 2.5rem;
    padding-right: 15px;
    font-family: 'Poppins', sans-serif;
    color: #2f3640;
    box-shadow: inset 0px 4px 8px rgba(0,0,0,0.1);
}

.buttons-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 12px;
}

button {
    border: none;
    outline: none;
    border-radius: 12px;
    font-size: 1.2rem;
    font-weight: 600;
    cursor: pointer;
    padding: 15px 0;
    transition: transform 0.1s, filter 0.2s;
    font-family: 'Poppins', sans-serif;
}

button:active {
    transform: scale(0.95);
}

/* Button Colors */
.digits {
    background-color: #353b48;
    color: white;
    box-shadow: 0 4px 0 #1e2229;
}

.operator-btn {
    background-color: #e1b12c; /* Yellow/Orange */
    color: white;
    box-shadow: 0 4px 0 #c29a26;
}

.action-btn {
    background-color: #e74c3c; /* Red */
    color: white;
    box-shadow: 0 4px 0 #c0392b;
}

.equal-btn {
    grid-row: span 2; /* Makes equal button tall */
    background-color: #44bd32; /* Green */
    color: white;
    height: 100%;
    box-shadow: 0 4px 0 #369628;
}

/* --- ARRAY PROGRAM STYLES --- */
.array-box {
    background-color: #2f3640;
    padding: 30px;
    border-radius: 20px;
    color: white;
    box-shadow: 0px 15px 25px rgba(0,0,0,0.2);
}

.input-group {
    margin-bottom: 15px;
    display: flex;
    flex-direction: column;
    gap: 5px;
}

.input-group.row {
    flex-direction: row;
    gap: 10px;
}

.array-box label {
    font-size: 0.9rem;
    color: #bdc3c7;
}

.array-box input {
    width: 100%;
    padding: 12px;
    border-radius: 8px;
    border: none;
    font-family: 'Poppins', sans-serif;
    font-size: 1rem;
    outline: none;
}

.array-box input:read-only {
    background-color: #3e4652;
    color: #44bd32; /* Green Text */
    font-weight: bold;
}

.success-btn {
    background-color: #44bd32;
    color: white;
    width: 80px;
    box-shadow: 0 4px 0 #369628;
}

.danger-btn {
    background-color: #e74c3c;
    color: white;
    width: 80px;
    box-shadow: 0 4px 0 #c0392b;
}

/* --- FOOTER --- */
.copyright {
    text-align: center;
    color: #7f8fa6;
    font-size: 0.8rem;
    margin-bottom: 20px;
}

/* --- RESPONSIVE DESIGN (MOBILE) --- */
@media (max-width: 400px) {
    .buttons-grid {
        gap: 8px;
    }
    
    button {
        padding: 12px 0;
        font-size: 1rem;
    }

    .display-container input {
        font-size: 2rem;
    }
}