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

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
    background: #f5f5f5;
    color: #333;
}

.header {
    background: #2c3e50;
    color: white;
    padding: 1rem 2rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.header .logo {
    font-size: 1.5rem;
    font-weight: bold;
}

.header nav a {
    color: white;
    text-decoration: none;
    margin-left: 1.5rem;
}

.header .user-info {
    display: flex;
    align-items: center;
    gap: 1rem;
}

.container {
    max-width: 1200px;
    margin: 2rem auto;
    padding: 0 1rem;
}

.card {
    background: white;
    border-radius: 8px;
    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
    padding: 1.5rem;
    margin-bottom: 1rem;
}

.btn {
    padding: 0.5rem 1rem;
    border: none;
    border-radius: 4px;
    cursor: pointer;
    font-size: 1rem;
}

.btn-primary {
    background: #3498db;
    color: white;
}

.btn-danger {
    background: #e74c3c;
    color: white;
}

.btn-success {
    background: #27ae60;
    color: white;
}

.btn:disabled {
    opacity: 0.5;
    cursor: not-allowed;
}

.difficulty-easy { color: #27ae60; }
.difficulty-medium { color: #f39c12; }
.difficulty-hard { color: #e74c3c; }

.result-badge {
    padding: 0.25rem 0.5rem;
    border-radius: 4px;
    font-weight: bold;
}

.result-ac { background: #27ae60; color: white; }
.result-wa { background: #e74c3c; color: white; }
.result-tle { background: #f39c12; color: white; }
.result-mle { background: #e67e22; color: white; }
.result-re { background: #9b59b6; color: white; }
.result-ce { background: #95a5a6; color: white; }

table {
    width: 100%;
    border-collapse: collapse;
}

th, td {
    padding: 0.75rem;
    text-align: left;
    border-bottom: 1px solid #ddd;
}

th {
    background: #f8f9fa;
    font-weight: 600;
}

.error-compare {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 1rem;
    margin-top: 1rem;
}

.error-box {
    background: #f8f9fa;
    padding: 1rem;
    border-radius: 4px;
    font-family: monospace;
}

.error-box.expected { border-left: 4px solid #27ae60; }
.error-box.actual { border-left: 4px solid #e74c3c; }

#loading {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(0,0,0,0.5);
    display: flex;
    justify-content: center;
    align-items: center;
    color: white;
    font-size: 1.5rem;
}

.error-line-highlight {
    background-color: #ffcccc !important;
    display: inline-block;
    width: 100%;
}

.similarity-badge {
    padding: 0.25rem 0.5rem;
    border-radius: 4px;
    font-weight: bold;
    background: #e74c3c;
    color: white;
}

.btn-secondary {
    background: #95a5a6;
    color: white;
}