/* General layout */
body {
    background: #e6f2ff;
    font-family: 'Segoe UI', sans-serif;
    padding-top: 70px;
    color: #003366;
}

/* Navbar */
.navbar-custom {
    background-color: #cce6ff;
    box-shadow: 0 2px 10px rgba(0,0,0,0.1);
}
.navbar-brand {
    font-weight: bold;
    color: #003366;
}
.navbar-nav .nav-link {
    color: #003366;
}
.navbar-toggler {
    border: none;
}
.navbar-toggler:focus {
    outline: none;
    box-shadow: none;
}

/* Calculator container */
.calc-container {
    max-width: 640px;
    margin: auto;
    background: #ffffff;
    padding: 2rem 1.5rem;
    border-radius: 20px;
    box-shadow: 0 6px 18px rgba(0, 0, 0, 0.1);
}

/* Input tiles */
.math-tile {
    background: #d9ecff;
    border-radius: 12px;
    padding: 1rem;
    font-weight: 500;
    font-size: 1rem;
    margin-bottom: 1rem;
    display: flex;
    flex-direction: column;
}
.math-tile label {
    margin-bottom: 0.5rem;
}
.calc-input {
    width: 100%;
    padding: 0.65rem 0.85rem;
    font-size: 1.1rem;
    border: 2px solid #99caff;
    border-radius: 10px;
    outline: none;
}
.calc-input:focus {
    border-color: #3399ff;
    box-shadow: 0 0 6px #66b3ff;
}

/* Buttons */
.calc-button {
    background-color: #3399ff;
    color: white;
    border: none;
    padding: 0.75rem 1.5rem;
    font-size: 1rem;
    border-radius: 12px;
    transition: all 0.2s ease;
    margin: 0.25rem;
    flex: 1 1 auto;
}
.calc-button:hover {
    background-color: #267acc;
    box-shadow: 0 0 10px #80c1ff;
}
.calc-button:active {
    transform: scale(0.97);
}

/* Output equation block */
.equation-display {
    font-family: monospace;
    background-color: #f0faff;
    border-left: 4px solid #66b3ff;
    padding: 0.75rem;
    margin-bottom: 1.5rem;
    font-size: 1.05rem;
    border-radius: 10px;
    word-wrap: break-word;
}

/* Button group */
.button-group {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
}
@media (max-width: 576px) {
    .calc-button {
        flex: 1 1 100%;
    }
}