* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Arial', sans-serif;
}

body {
    width: 100%;
    height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
    background: linear-gradient(45deg, #0a0a0a, #3a4452);
}

h1 {
    padding-bottom: 23px;
    top: 20px;
    width: 100%;
    font-size: 40px;
    text-align: center;
    font-weight: 600;
    background: linear-gradient(90deg, #fb7c14, #6dee0a, #2196f3, #ff004f);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    color: transparent;
    transition: filter 0.3s;
}

h1:hover {
    filter: brightness(1.3) drop-shadow(0 0 8px #fb7c14);
    letter-spacing: 2px;
    cursor: pointer;
}

.calculator {
    border: 1px solid #717377;
    padding: 20px;
    border-radius: 16px;
    background: transparent;
    box-shadow: 0px 3px 15px rgba(0, 0, 0, 0.1);
    transition: box-shadow 0.4s ease, transform 0.4s ease;
}

.calculator:hover {
    box-shadow: 0 0 20px rgba(251, 124, 20, 0.7);
    transform: scale(1.1);
}

input {
    width: 320px;
    border: none;
    padding: 24px;
    margin: 10px;
    background: transparent;
    box-shadow: 0px 2px 5px rgba(84, 84, 84, 0.1);
    font-size: 40px;
    text-align: right;
    cursor: pointer;
    color: #fff;
    border-radius: 16px;
}

input::placeholder {
    color: #fff;
    opacity: 0.6;
}

button {
    width: 60px;
    height: 60px;
    margin: 10px;
    border: none;
    border-radius: 50%;
    background: transparent;
    color: #fff;
    font-size: 20px;
    font-weight: bold;
    cursor: pointer;
    box-shadow: -8px -8px 15px rgba(255, 255, 255, 0.1);
}

button:hover {
    background: rgba(255, 255, 255, 0.2);
    transform: scale(1.1);
}

.equal-btn {
    background-color: #fb7c14;
}

.operator-btn {
    color: #6dee0a;
}

footer {
    width: 100%;
    background: #212227;
    color: #ccc;
    text-align: center;
    padding: 14px 0 10px 0;
    font-size: 1rem;
    letter-spacing: 0.5px;
    position: fixed;
    bottom: 0;
    left: 0;
}

.copyright i {
    color: #ff004f;
}