.modeling-nav .modeling-nav-item { width: 100%; text-align: left; font: inherit; border: 0; border-left: 3px solid transparent; background: transparent; color: #b7c8df; }
.modeling-nav .modeling-nav-item.active { border-left-color: #65a3f6; background: #1c304c; color: #fff; }
.lesson-selector { display: grid; grid-template-columns: repeat(4,minmax(0,1fr)); max-width: 700px; gap: 10px; margin: 22px 0 18px; }
.lesson-topic { min-height: 70px; min-width: 0; border: 1px solid #394558; border-radius: 6px; background: #171f2c; color: #c5d3e4; font: inherit; padding: 10px 6px; cursor: pointer; transition: background .18s, border-color .18s; }
.lesson-topic i { display: block; font-size: 20px; margin-bottom: 8px; color: #8cb9e7; }
.lesson-topic span { display: block; font-size: 13px; overflow-wrap: anywhere; }
.lesson-topic.active { background: #25374b; border-color: #8cb9e7; color: #fff; }
.lesson-topic:hover { border-color: #c7d8eb; }
.lesson-host { min-width: 0; }
.lesson-loading { min-height: 340px; display: grid; align-content: center; justify-items: center; gap: 16px; color: #adbed3; }
.lesson-workbench { min-width: 0; }
.lesson-meta { display: flex; align-items: baseline; justify-content: space-between; flex-wrap: wrap; gap: 8px; margin-bottom: 12px; }
.lesson-meta h5 { font-size: 18px; line-height: 1.5; margin: 0; }
.lesson-phase { color: #ddba77; font-size: 12px; }
.lesson-viewport { position: relative; height: 380px; width: 100%; background: #101620; touch-action: none; overflow: hidden; cursor: grab; }
.lesson-viewport:active { cursor: grabbing; }
.lesson-viewport canvas { display: block; width: 100%; height: 100%; }
.lesson-status { position: absolute; inset: 0; display: grid; place-items: center; padding: 20px; text-align: center; pointer-events: none; }
.lesson-status[hidden] { display: none; }
.lesson-transport { display: flex; align-items: center; flex-wrap: wrap; gap: 8px; border-bottom: 1px solid #303b4c; padding: 12px 0; }
.lesson-tool { display: inline-grid; place-items: center; width: 36px; height: 36px; padding: 0; border: 1px solid #40506a; border-radius: 5px; background: #202b3a; color: #edf3fa; font-size: 14px; cursor: pointer; }
.lesson-tool:hover { background: #354862; }
.lesson-transport .lesson-progress { flex: 1; min-width: 100px; width: 100px; accent-color: #8cb9e7; height: 28px; padding: 0; }
.lesson-progress-value { min-width: 38px; font-size: 12px; color: #b6c5d5; font-variant-numeric: tabular-nums; }
.lesson-transport select { background: #172231; border: 1px solid #40506a; border-radius: 5px; color: #d6e2ef; font: inherit; font-size: 12px; width: 66px; height: 36px; padding: 0 4px; }
.lesson-options { display: flex; align-items: center; flex-wrap: wrap; gap: 14px; padding: 12px 0; font-size: 13px; color: #b6c5d5; }
.lesson-options label { display: inline-flex; align-items: center; gap: 6px; }
.lesson-options input[type=checkbox] { accent-color: #8cb9e7; width: 15px; height: 15px; }
.lesson-parameter { flex: 1; min-width: 220px; }
.lesson-parameter input { min-width: 70px; flex: 1; width: 100px; height: 28px; padding: 0; accent-color: #ddba77; }
.lesson-parameter output { min-width: 36px; text-align: right; font-variant-numeric: tabular-nums; }
.lesson-content { display: grid; grid-template-columns: minmax(0,1.3fr) minmax(0,1fr); gap: 22px; padding: 16px 0; border-top: 1px solid #303b4c; }
.lesson-content h6 { margin: 0 0 5px; color: #ddba77; font-size: 12px; font-weight: 500; }
.lesson-content p { margin: 0; font-size: 13px; color: #b7c8df; line-height: 1.8; }
.lesson-content .lesson-check { grid-column: 1 / -1; }
.lesson-question { border: 0; border-top: 1px solid #303b4c; margin: 12px 0 0; padding: 16px 0; min-width: 0; }
.lesson-question legend { font-size: 13px; color: #ddba77; padding-right: 10px; }
.lesson-question > p { font-size: 14px; color: #d6e2ef; margin: 0 0 10px; }
.lesson-answers { display: flex; gap: 12px 20px; flex-wrap: wrap; }
.lesson-answers label { display: inline-flex; align-items: flex-start; gap: 7px; font-size: 13px; color: #b7c8df; cursor: pointer; }
.lesson-answers input { width: 15px; height: 15px; margin: 3px 0; flex-shrink: 0; accent-color: #80bda7; }
.lesson-question .lesson-feedback { margin: 12px 0 0; color: #b8cadc; font-size: 13px; line-height: 1.8; min-height: 24px; }
.lesson-feedback[data-correct=true] { color: #95d3b3; }
.lesson-feedback[data-correct=false] { color: #ecc586; }
.modeling-display :focus-visible, .render-settings :focus-visible { outline: 2px solid #b5d4f8; outline-offset: 3px; }
.render-settings { border-radius: 8px; }
.render-settings-summary { display: flex; align-items: center; justify-content: space-between; gap: 12px; list-style: none; cursor: pointer; font-size: 16px; color: #edf2f7; }
.render-settings-summary::-webkit-details-marker { display: none; }
.render-settings-summary span { display: flex; align-items: center; gap: 8px; }
.render-settings-summary > i { font-size: 12px; transition: transform .2s; }
.render-settings[open] .render-settings-summary > i { transform: rotate(180deg); }
.render-copy-toolbar { display: flex; justify-content: flex-end; padding: 16px 0 12px; }
.render-settings .param-group-title { width: 100%; border: 0; font-family: inherit; text-align: left; }
@media (max-width: 700px) {
    .lesson-selector { gap: 6px; }
    .lesson-topic { padding: 10px 3px; }
    .lesson-topic span { font-size: 12px; }
    .lesson-viewport { height: 330px; }
    .lesson-meta h5 { font-size: 17px; }
    .lesson-content { grid-template-columns: 1fr; gap: 12px; }
    .lesson-transport { gap: 6px; }
    .lesson-transport .lesson-progress { order: 2; flex-basis: calc(100% - 52px); }
    .lesson-progress-value { order: 3; }
    .lesson-parameter { flex-basis: 100%; }
    .render-settings { padding: 18px 14px; }
    .render-settings-summary { font-size: 14px; }
    #render > div[style*="display: flex"] > div { min-width: 0 !important; flex-basis: 100% !important; }
}
@media (prefers-reduced-motion: reduce) { .lesson-topic, .render-settings-summary > i { transition: none; } }