/* Reset and Base Styles */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: Arial, sans-serif;
    background-color: #f5f5f5;
    padding: 20px;
    line-height: 1.6;
}

/* Container */
.container {
    max-width: 600px;
    margin: 0 auto;
    background-color: #ffffff;
    border: 2px solid #000000;
    padding: 0;
}

/* Header */
header {
    background-color: #000000;
    color: #ffffff;
    padding: 20px;
    border-bottom: 2px solid #000000;
}

header h1 {
    font-size: 24px;
    font-weight: bold;
}

/* Main */
main {
    padding: 30px;
}

/* Input Group */
.input-group {
    margin-bottom: 30px;
    display: grid;
    grid-template-columns: auto 1fr auto auto;
    gap: 10px;
    align-items: center;
}

.input-group label {
    font-weight: bold;
}

.input-group input {
    padding: 8px;
    border: 2px solid #000000;
    font-size: 14px;
    background-color: #ffffff;
}

.input-group input:focus {
    outline: none;
    background-color: #f0f0f0;
}

.input-group select {
    padding: 8px;
    border: 2px solid #000000;
    font-size: 14px;
    background-color: #ffffff;
    cursor: pointer;
}

.input-group select:focus {
    outline: none;
    background-color: #f0f0f0;
}

/* Operator Group */
.operator-group {
    margin-bottom: 30px;
    display: grid;
    grid-template-columns: auto 1fr;
    gap: 10px;
    align-items: center;
    width: 66%;
}

.operator-group label {
    font-weight: bold;
}

.operator-group select {
    padding: 8px;
    border: 2px solid #000000;
    font-size: 14px;
    background-color: #ffffff;
    cursor: pointer;
}

.operator-group select:focus {
    outline: none;
    background-color: #f0f0f0;
}

/* Button Group */
.button-group {
    margin-bottom: 30px;
    text-align: center;
}

.button-group button {
    padding: 12px 40px;
    border: 2px solid #000000;
    background-color: #ffffff;
    font-size: 16px;
    font-weight: bold;
    cursor: pointer;
}

.button-group button:hover {
    background-color: #000000;
    color: #ffffff;
}

.button-group button:active {
    background-color: #333333;
}

/* Result Area */
.result-area {
    margin-bottom: 20px;
    padding: 20px;
    border: 2px solid #000000;
    background-color: #ffffff;
}

.result-label {
    font-weight: bold;
    font-size: 16px;
    margin-bottom: 10px;
}

.result-value {
    font-size: 24px;
    font-weight: bold;
    color: #000000;
    min-height: 30px;
}

.result-value.true {
    color: #008000;
}

.result-value.false {
    color: #ff0000;
}

/* Message Area */
.message-area {
    padding: 20px;
    border: 2px solid #000000;
    background-color: #ffffff;
}

.message-text {
    font-size: 14px;
    color: #333333;
    min-height: 20px;
    font-family: monospace;
}

.message-text.error {
    color: #ff0000;
    font-weight: bold;
}

.message-text.success {
    color: #000000;
}