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

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    min-height: 100vh;
    color: #333;
    padding: 20px;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    background: white;
    border-radius: 15px;
    box-shadow: 0 10px 30px rgba(0,0,0,0.2);
    overflow: hidden;
}

header {
    background: linear-gradient(45deg, #3498db, #2980b9);
    color: white;
    padding: 30px;
}

.header-content {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    text-align: center;
}

.title-section {
    flex: 1;
}

.home-link {
    display: inline-block;
    font-size: 2rem;
    color: white;
    text-decoration: none;
    padding: 10px;
    border-radius: 50%;
    transition: all 0.3s ease;
    background: rgba(255, 255, 255, 0.1);
    backdrop-filter: blur(10px);
    border: 2px solid rgba(255, 255, 255, 0.2);
}

.home-link:hover {
    background: rgba(255, 255, 255, 0.2);
    transform: scale(1.1);
    box-shadow: 0 4px 15px rgba(0, 0, 0, 0.3);
}

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

header p {
    font-size: 1.1rem;
    opacity: 0.9;
}

.slide-rule-container {
    padding: 40px 60px;
    background: #f8f9fa;
    display: flex;
    justify-content: center;
}

.slide-rule {
    position: relative;
    width: 1000px;
    height: 180px;
    background: #2c3e50;
    border-radius: 10px;
    box-shadow: 0 5px 15px rgba(0,0,0,0.3);
    display: flex;
    flex-direction: column;
    overflow: visible;
}

.scale {
    position: relative;
    height: 50%;
    background: #ecf0f1;
    border: 2px solid #34495e;
    display: flex;
    flex-direction: column;
}

.fixed-scale {
    border-bottom: none;
    border-radius: 10px 10px 0 0;
}

.sliding-scale {
    border-top: none;
    border-bottom: none;
    background: #d5dbdb;
}

.l-scale {
    border-top: none;
    border-radius: 0 0 10px 10px;
    background: #bdc3c7;
}

.scale-label {
    background: #34495e;
    color: white;
    text-align: center;
    padding: 4px;
    font-weight: bold;
    font-size: 0.9rem;
}

.sliding-scale .scale-label {
    background: #000;
    color: white;
}

.scale-value {
    position: absolute;
    top: 20%;
    right: 10px;
    transform: translateY(-50%);
    background: rgba(231, 76, 60, 0.95);
    color: white;
    padding: 2px 6px;
    border-radius: 4px;
    font-size: 0.8rem;
    font-weight: bold;
    white-space: nowrap;
    z-index: 30;
    pointer-events: none;
    box-shadow: 0 2px 4px rgba(0,0,0,0.3);
    border: 1px solid white;
}

.scale-markings {
    position: relative;
    flex: 1;
    background: linear-gradient(to bottom, #ecf0f1, #d5dbdb);
}

.marking {
    position: absolute;
    top: 0;
    width: 2px;
    height: 100%;
    background: #2c3e50;
    cursor: pointer;
    transition: background-color 0.2s ease;
}

.marking:hover,
.marking:focus {
    background: #e74c3c;
    width: 4px;
}

.marking.major {
    width: 4px;
    background: #2c3e50;
}

.marking.major:hover,
.marking.major:focus {
    width: 6px;
    background: #e74c3c;
}

.marking-label {
    position: absolute;
    left: 50%;
    top: 0;
    transform: translateX(-50%);
    background: rgba(44, 62, 80, 0.9);
    color: white;
    padding: 2px 6px;
    border-radius: 3px;
    font-size: 0.7rem;
    font-weight: bold;
    pointer-events: none;
    opacity: 0;
    transition: opacity 0.2s ease;
    white-space: nowrap;
    z-index: 20;
}

.marking:hover .marking-label,
.marking:focus .marking-label {
    opacity: 1;
}

.side-label {
    opacity: 1;
}

.side-label {
    position: absolute;
    top: 50%;
    transform: translateY(-50%);
    background: rgba(44, 62, 80, 0.9);
    color: white;
    padding: 2px 6px;
    border-radius: 3px;
    font-size: 0.8rem;
    font-weight: bold;
    pointer-events: none;
    white-space: nowrap;
    z-index: 20;
}

.side-label.left {
    left: 50%;
    transform: translate(-50%, -50%);
}

.side-label.right {
    right: -30px;
}

.hairline {
    position: absolute;
    top: 0;
    left: 50%;
    width: 2px;
    height: 100%;
    background: #e74c3c;
    transform: translateX(-50%);
    z-index: 10;
    pointer-events: none;
    box-shadow: 0 0 5px rgba(231, 76, 60, 0.5);
}



.controls {
    padding: 30px;
    background: white;
    border-bottom: 1px solid #dee2e6;
}

.control-group {
    display: flex;
    align-items: center;
    margin-bottom: 20px;
    gap: 15px;
}

.control-group label {
    font-weight: 600;
    min-width: 120px;
}

.control-group input[type="range"] {
    flex: 1;
    height: 8px;
    border-radius: 4px;
    background: #ddd;
    outline: none;
    -webkit-appearance: none;
}

.control-group input[type="range"]::-webkit-slider-thumb {
    -webkit-appearance: none;
    appearance: none;
    width: 20px;
    height: 20px;
    border-radius: 50%;
    background: #3498db;
    cursor: pointer;
    box-shadow: 0 2px 5px rgba(0,0,0,0.2);
}

.control-group input[type="range"]::-moz-range-thumb {
    width: 20px;
    height: 20px;
    border-radius: 50%;
    background: #3498db;
    cursor: pointer;
    border: none;
    box-shadow: 0 2px 5px rgba(0,0,0,0.2);
}

.control-group span {
    font-weight: bold;
    color: #3498db;
    min-width: 60px;
    text-align: right;
}

.info-panel {
    padding: 30px;
    background: #f8f9fa;
}

.info-panel h2 {
    color: #2c3e50;
    margin-bottom: 15px;
}

.info-panel ul {
    list-style-type: none;
    padding-left: 0;
}

.info-panel li {
    padding: 8px 0;
    border-bottom: 1px solid #dee2e6;
    position: relative;
    padding-left: 25px;
}

.info-panel li:before {
    content: "•";
    color: #3498db;
    font-weight: bold;
    position: absolute;
    left: 0;
}

.info-panel li:last-child {
    border-bottom: none;
}

/* Mobile optimizations */
@media (max-width: 768px) {
    .slide-rule {
        width: 600px;
        height: 150px;
    }
    
    .control-group {
        flex-direction: column;
        align-items: stretch;
        gap: 10px;
    }
    
    .control-group label {
        min-width: auto;
    }
    
    .control-group span {
        text-align: center;
    }
}