:root {
    --primary-color: #007bff;
    --primary-light: #e6f2ff;
    --background-color: #f8f9fa;
    --card-color: #ffffff;
    --text-color: #333;
    --text-light: #666;
    --border-color: #dee2e6;
    --error-color: #d9534f;
    --success-color: #5cb85c;
    --font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
    --border-radius: 8px;
}

.vdot-calculator-container {
    font-family: var(--font-family);
    background-color: var(--background-color);
    padding: 20px;
    border-radius: var(--border-radius);
    max-width: 700px;
    margin: 20px auto;
    box-shadow: 0 4px 12px rgba(0,0,0,0.05);
    color: var(--text-color);
}

/* --- Form --- */
.vdot-form fieldset {
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius);
    padding: 15px;
    margin-bottom: 15px;
}
.vdot-form legend {
    padding: 0 10px;
    font-weight: 600;
    color: var(--primary-color);
}

.form-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 15px;
}
.form-group.span-two { grid-column: span 2; }
.form-group label {
    display: block;
    margin-bottom: 5px;
    font-size: 0.9em;
    font-weight: 500;
}
.form-group input, .form-group select {
    width: 100%;
    padding: 10px;
    border: 1px solid var(--border-color);
    border-radius: 6px;
    font-size: 1em;
    background-color: #fff;
    transition: border-color 0.2s;
}
.form-group input:focus, .form-group select:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 2px var(--primary-light);
}

.time-input { grid-column: span 2; }
.time-inputs {
    display: flex;
    align-items: center;
    gap: 5px;
}
.time-inputs input { text-align: center; }
.time-inputs span { font-size: 1.2em; color: var(--text-light); }

.custom-distance-inputs {
    display: flex;
    gap: 10px;
}
.custom-distance-inputs input { flex-grow: 1; }
.custom-distance-inputs select { width: 120px; }

.calculate-btn {
    width: 100%;
    padding: 12px;
    font-size: 1.1em;
    font-weight: 600;
    color: #fff;
    background-color: var(--primary-color);
    border: none;
    border-radius: 6px;
    cursor: pointer;
    transition: background-color 0.2s;
}
.calculate-btn:hover { background-color: #0056b3; }

.optional-section summary {
    cursor: pointer;
    font-weight: 500;
    color: var(--text-color);
    margin-bottom: 10px;
}
.optional-section summary:hover { color: var(--primary-color); }
.summary-hint {
    font-size: 0.8em;
    font-weight: 400;
    color: var(--text-light);
}
.optional-section[open] > summary { margin-bottom: 15px; }
.optional-section fieldset { margin: 0; }

/* --- Results --- */
.vdot-results-container {
    margin-top: 25px;
    padding: 20px;
    background-color: var(--card-color);
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius);
}

.results-summary {
    display: flex;
    justify-content: space-around;
    align-items: center;
    text-align: center;
    margin-bottom: 20px;
    padding-bottom: 20px;
    border-bottom: 1px solid var(--border-color);
    flex-wrap: wrap;
    gap: 20px;
}
.vdot-score-display h3 {
    margin: 0 0 5px;
    font-size: 1em;
    color: var(--text-light);
    font-weight: 500;
}
.score-value {
    font-size: 3.5em;
    font-weight: 700;
    color: var(--primary-color);
    margin: 0;
    line-height: 1;
}
.score-level {
    margin: 5px 0 0;
    font-weight: 500;
    color: var(--text-color);
}

/* Gauge */
.vdot-gauge-container { width: 150px; }
.vdot-gauge {
    position: relative;
    width: 150px;
    height: 75px;
    overflow: hidden;
}
.gauge-arc {
    width: 100%;
    height: 100%;
    background: conic-gradient(from 180deg, #d9534f, #f0ad4e, #5cb85c);
    border-radius: 150px 150px 0 0;
}
.gauge-pointer {
    position: absolute;
    bottom: 0;
    left: 50%;
    width: 2px;
    height: 70px;
    background-color: var(--text-color);
    transform-origin: bottom center;
    transition: transform 0.5s ease-out;
    transform: translateX(-50%) rotate(-90deg); /* Start position */
}
.gauge-center {
    position: absolute;
    bottom: -5px;
    left: 50%;
    transform: translateX(-50%);
    width: 10px;
    height: 10px;
    background-color: var(--text-color);
    border-radius: 50%;
}
.gauge-labels {
    display: flex;
    justify-content: space-between;
    font-size: 0.7em;
    color: var(--text-light);
    margin-top: -5px;
}

/* Tabs */
.results-tabs {
    display: flex;
    border-bottom: 1px solid var(--border-color);
    margin-bottom: 20px;
}
.tab-link {
    padding: 10px 15px;
    border: none;
    background: none;
    cursor: pointer;
    font-size: 1em;
    font-weight: 500;
    color: var(--text-light);
    border-bottom: 3px solid transparent;
    margin-bottom: -1px;
}
.tab-link.active {
    color: var(--primary-color);
    border-bottom-color: var(--primary-color);
}

.tab-content { display: none; }
.tab-content.active { display: block; animation: fadeIn 0.5s; }

@keyframes fadeIn { from { opacity: 0; } to { opacity: 1; } }

h4 { margin-top: 0; }
.table-wrapper { overflow-x: auto; }
table {
    width: 100%;
    border-collapse: collapse;
}
th, td {
    padding: 10px;
    text-align: left;
    border-bottom: 1px solid var(--border-color);
}
th { font-size: 0.9em; color: var(--text-light); }
tbody tr:last-child td { border-bottom: none; }
tbody tr:nth-child(even) { background-color: #f8f9fa; }

/* Pace Chart */
.paces-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 20px;
    align-items: flex-start;
}
.pace-chart-container h5 { text-align: center; margin: 0 0 15px; }
.pace-chart .pace-bar-group {
    display: flex;
    align-items: center;
    margin-bottom: 10px;
    font-size: 0.8em;
}
.pace-bar-group .pace-label {
    width: 60px;
    flex-shrink: 0;
    text-align: right;
    padding-right: 10px;
    color: var(--text-light);
}
.pace-bar-group .bar-wrapper {
    flex-grow: 1;
    background-color: #e9ecef;
    border-radius: 4px;
    height: 20px;
}
.pace-bar-group .bar {
    height: 100%;
    border-radius: 4px;
    transition: width 0.5s ease-out;
    background-color: var(--primary-color);
}

/* Insights */
.insight-card {
    background-color: #f8f9fa;
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius);
    padding: 15px;
    margin-bottom: 15px;
}
.insight-card h5 { margin: 0 0 10px; }
.insight-description { font-size: 0.9em; color: var(--text-light); margin: 5px 0 0; }
.progress-bar-container {
    height: 10px;
    background-color: #e9ecef;
    border-radius: 5px;
    overflow: hidden;
    margin: 10px 0;
}
.progress-bar {
    height: 100%;
    width: 0%;
    background-color: var(--success-color);
    border-radius: 5px;
    transition: width 0.5s ease-out;
}
.tooltip-icon {
    display: inline-block;
    width: 16px;
    height: 16px;
    background-color: var(--text-light);
    color: white;
    border-radius: 50%;
    text-align: center;
    font-size: 12px;
    line-height: 16px;
    cursor: help;
    position: relative;
}
.tooltip-icon:hover::after {
    content: attr(data-tooltip);
    position: absolute;
    bottom: 120%;
    left: 50%;
    transform: translateX(-50%);
    background-color: #333;
    color: #fff;
    padding: 5px 10px;
    border-radius: 4px;
    font-size: 0.8em;
    width: 200px;
    text-align: center;
    z-index: 10;
}


/* Utility & Responsive */
.hidden { display: none !important; }

.error-message {
    background-color: #f8d7da;
    color: #721c24;
    border: 1px solid #f5c6cb;
    padding: 10px;
    border-radius: 6px;
    margin-top: 15px;
}

@media (max-width: 768px) {
    .vdot-calculator-container { padding: 15px; }
    .form-grid { grid-template-columns: 1fr; }
    .form-group.span-two { grid-column: span 1; }
    .time-input { grid-column: span 1; }
    .results-summary { flex-direction: column; }
    .paces-grid { grid-template-columns: 1fr; }
    .pace-chart-container { margin-top: 20px; }
}



    h1,h2,h3{line-height:1.25; margin:16px 0 8px}
    h1{font-size:2rem}
    h2{font-size:1.5rem; margin-top:28px}
    h3{font-size:1.15rem; margin-top:20px; color:#0f172a}
    p{margin:10px 0}
    .lead{font-size:1.05rem; color:#0f172a}
    .muted{color:var(--muted)}
    .card{
      background:var(--card); border:1px solid var(--border);
      border-radius:14px; padding:16px; margin:16px 0;
    }
    .grid{display:grid; gap:16px}
    .grid.cols-2{grid-template-columns:repeat(auto-fit,minmax(280px,1fr))}
    nav a{color:var(--accent); text-decoration:none}
    nav{margin:12px 0 24px}
    code{background:#f1f5f9; padding:2px 6px; border-radius:6px}
    ul{padding-left:18px}
    .faq details{border:1px solid var(--border); border-radius:12px; padding:12px; margin:10px 0; background:#fff}
    .faq summary{cursor:pointer; font-weight:600}
    footer{padding-bottom:56px; color:var(--muted)}