* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    min-height: 100vh;
    padding: 20px;
}

.container {
    max-width: 1000px;
    margin: 0 auto;
    background: white;
    border-radius: 20px;
    overflow: hidden;
    border: 3px solid #ff8c00;
}

.header {
    background: #ff8c00;
    color: white;
    padding: 40px;
    text-align: center;
}

.header h1 {
    font-size: 2.5em;
    margin-bottom: 10px;
}

.header p {
    font-size: 1.1em;
    opacity: 0.95;
}

.converter {
    padding: 40px;
}

.input-group {
    margin-bottom: 25px;
}

.input-group label {
    display: block;
    margin-bottom: 8px;
    font-weight: 600;
    color: #000;
    font-size: 1.1em;
}

.input-group input,
.input-group select {
    width: 100%;
    border: 2px solid #000;
    border-radius: 10px;
    font-size: 1.1em;
    transition: all 0.3s;
}

.input-group input:focus,
.input-group select:focus {
    outline: none;
    border-color: #ff8c00;
    box-shadow: 0 0 0 3px rgba(255, 140, 0, 0.2);
}

.input-group select optgroup {
    font-weight: bold;
    color: #ff8c00;
    font-style: normal;
}

.input-group select option {
    color: #000;
    padding: 5px;
}

.quick-buttons {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 15px;
    margin: 30px 0;
}

.quick-btn {
    padding: 20px;
    background: #ff8c00;
    color: white;
    border: 2px solid #ff8c00;
    border-radius: 10px;
    font-size: 1.1em;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s;
}

.quick-btn:hover {
    background: white;
    color: #ff8c00;
    transform: translateY(-3px);
    box-shadow: 0 10px 20px rgba(255, 140, 0, 0.3);
}

.result {
    background: #000;
    color: white;
    padding: 30px;
    border-radius: 15px;
    text-align: center;
    margin-top: 30px;
    font-size: 1.5em;
    font-weight: bold;
    border: 3px solid #ff8c00;
}

.result strong {
    color: #ff8c00;
}

.explanation {
    padding: 40px;
    background: #f9f9f9;
}

.explanation h2 {
    color: #ff8c00;
    margin-bottom: 20px;
    font-size: 2em;
}

.explanation h3 {
    color: #000;
    margin-top: 30px;
    margin-bottom: 15px;
    font-size: 1.5em;
}

.explanation p {
    line-height: 1.8;
    color: #333;
    margin-bottom: 15px;
    font-size: 1.05em;
}

.formula {
    background: white;
    padding: 20px;
    border-radius: 10px;
    margin: 20px 0;
    border-left: 4px solid #ff8c00;
    border: 2px solid #000;
}

table {
    width: 100%;
    border-collapse: collapse;
    margin: 20px 0;
    background: white;
    overflow: hidden;
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.1);
}

th {
    background: #ff8c00;
    color: white;
    padding: 15px 10px;
    text-align: center;
    font-weight: 600;
    border: 1px solid #000;
}

td {
    padding: 12px 10px;
    border: 1px solid #000;
    text-align: center;
}

tr:nth-child(even) {
    background: #f9f9f9;
}

tr:hover {
    background: rgba(255, 140, 0, 0.1);
}

.table-container {
    margin-bottom: 40px;
}

.table-title {
    font-size: 1.3em;
    font-weight: 600;
    color: #000;
    margin: 30px 0 15px 0;
}