body {
    background: linear-gradient(135deg, #f7d9d9, #dbe2ef);
    height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
    font-family: "Segoe UI", sans-serif;
}

.container {
    backdrop-filter: blur(15px);
    background: rgba(255, 255, 255, 0.35);
    box-shadow: 0 8px 25px rgba(0, 0, 0, 0.15);
    border-radius: 25px;
    padding: 25px;
    width: 380px;
}

.calc-input {
    background: rgba(255, 255, 255, 0.55);
    border-radius: 15px;
    padding: 20px;
    font-size: 40px;
    text-align: right;
    color: #333;
    box-shadow: inset 0 0 10px rgba(0,0,0,0.1);
}

.buttons {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 12px;
    margin-top: 20px;
}

button {
    height: 75px;
    border-radius: 18px;
    border: none;
    font-size: 24px;
    cursor: pointer;
    transition: 0.15s;
    background: rgba(255, 255, 255, 0.55);
    box-shadow: 0 4px 12px rgba(0,0,0,0.1);
}

button:hover {
    background: rgba(255, 255, 255, 0.75);
    transform: translateY(-3px);
}

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

.number {
    color: #333;
}

.classic-operations {
    background: #ffb6a0;
    color: #fff;
}

.classic-operations:hover {
    background: #ff9d85;
}

.other-operations {
    background: #cddafd;
    color: #2c3e50;
}

.change-mode {
    background: #b8e994;
    color: #2d572c;
}