:root {
    --dark-gray: #333333;
    --light-gray: #f2f2f2;
    --orange: #ff8d00;
    --white: #ffffff;
    --black: #000000;
    --green: #00ff00;
    --red: #ff0000;
    --blue: #0000ff;
    --yellow: #ffff00;
    --cyan: #00ffff;
    --magenta: #ff00ff;
}

body {
    background-color: var(--dark-gray);
    color: var(--white);
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    min-height: 100vh;
    margin: 0;
    font-family: Arial, sans-serif;
}

header {
    text-align: center;
    margin-bottom: 20px;
    color: var(--orange);
}

.container {
    display: flex;
    flex-direction: column;
    align-items: center;
    width: 350px;
    border: 2px solid var(--orange);
    margin: 20px;
    padding: 20px;
    border-radius: 10px;
    box-shadow: 0 0 10px rgba(0, 0, 0, 0.2);
}

.display {
    display: flex;
    flex-direction: column;
    width: 100%;
    margin-bottom: 20px;
    background-color: rgba(0, 0, 0, 0.2);
    border-radius: 5px;
    padding: 10px;
    box-sizing: border-box;
}

.syntax {
    min-height: 30px;
    font-size: 18px;
    margin-bottom: 5px;
    word-wrap: break-word;
    color: var(--white);
    text-align: left;
}

.result {
    min-height: 40px;
    font-size: 24px;
    font-weight: bold;
    color: var(--orange);
    text-align: right;
    word-wrap: break-word;
}

.buttons {
    display: flex;
    flex-direction: column;
    gap: 10px;
    width: 100%;
}

.row {
    display: flex;
    gap: 10px;
    justify-content: space-between;
}

button {
    flex: 1;
    padding: 15px 0;
    font-size: 18px;
    border: none;
    border-radius: 10px;
    cursor: pointer;
    transition: all 0.2s ease-in-out;
    background-color: var(--black);
}

button:hover {
    background-color: #222;
    transform: translateY(-2px);
}

button:active {
    transform: translateY(1px);
}

.operator {
    color: var(--green);
    font-weight: bold;
}

.number {
    color: var(--orange);
    font-weight: bold;
}

.sp {
    color: var(--blue);
    font-weight: bold;
}

.sign {
    color: var(--magenta);
    font-weight: bold;
}

#calculate {
    background-color: #222;
}

#calculate:hover {
    background-color: var(--orange);
    color: var(--black);
}

footer {
    text-align: center;
    margin-top: 20px;
    color: var(--orange);
}