/* T1 frame lesson: slot grid, moving frames, and the clock experiment. */
.xr-tdm { --tdm-protection: #b7a0ff; --tdm-scada: #f2c66d; --tdm-voice: #72e5ef; --tdm-data: #87e8a0; --tdm-spare: #2a4350; --tdm-bad: #ff7b6b; }
.xr-tdm [data-service=protection] { --c: var(--tdm-protection); }
.xr-tdm [data-service=scada] { --c: var(--tdm-scada); }
.xr-tdm [data-service=voice] { --c: var(--tdm-voice); }
.xr-tdm [data-service=data] { --c: var(--tdm-data); }
.xr-tdm [data-service=spare] { --c: var(--tdm-spare); }

.xr-tdm .xr-tdm-step { margin: 28px 0 4px; padding-top: 18px; border-top: 1px solid #1d3742; color: #e6f7fb; font: 600 15px/1.4 var(--sans); }
.xr-tdm .xr-tdm-help { margin: 0 0 10px; color: #9bb5c3; font: 400 13px/1.5 var(--sans); }
.xr-tdm-legend { display: flex; flex-wrap: wrap; gap: 6px 16px; margin: 0 0 12px; padding: 0; list-style: none; color: #b3cdd7; font: 500 12px/1.4 var(--sans); }
.xr-tdm-legend li { display: flex; align-items: center; gap: 6px; }
.xr-tdm-swatch { display: inline-block; flex: none; width: 12px; height: 12px; border-radius: 3px; background: var(--c); }

.xr-tdm-slots { display: grid; grid-template-columns: repeat(12, minmax(0, 1fr)); gap: 5px; }
.xr-tdm-slot {
  display: flex; flex-direction: column; align-items: center; justify-content: center; gap: 2px;
  min-height: 52px; padding: 4px 2px; border: 1px solid color-mix(in srgb, var(--c) 70%, transparent); border-radius: 6px;
  background: color-mix(in srgb, var(--c) 16%, #0a1d27); color: #e6f7fb; cursor: pointer;
}
.xr-tdm-slot b { font: 600 13px/1 var(--mono); }
.xr-tdm-slot span { font: 500 8.5px/1 var(--mono); letter-spacing: .04em; color: #b3cdd7; }
.xr-tdm-slot[data-service=spare] { border-style: dashed; border-color: #35505d; }
.xr-tdm-slot:hover { background: color-mix(in srgb, var(--c) 28%, #0a1d27); }
.xr-tdm-slot:focus-visible { outline: 2px solid #72e5ef; outline-offset: 2px; }
.xr-tdm-usage { margin: 10px 0 0; color: #b3cdd7; font: 400 13px/1.5 var(--mono); }
.xr-tdm-usage strong { color: #e6f7fb; }

.xr-tdm-link { display: grid; grid-template-columns: auto minmax(0, 1fr) auto; align-items: center; gap: 8px; margin-top: 12px; }
.xr-tdm-end { padding: 10px 8px; border: 1px solid #456775; border-radius: 6px; background: #102630; color: #d2e7ef; font: 600 10px/1 var(--mono); letter-spacing: .08em; }
.xr-tdm-lane { position: relative; overflow: hidden; height: 34px; border-block: 1px solid #35505d; background: #0a1d27; }
.xr-tdm-track { --frame: 196px; position: absolute; top: 8px; left: 0; display: flex; animation: xr-tdm-flow 1.25s linear infinite; }
.xr-tdm-frame { display: flex; flex-direction: row-reverse; gap: 1px; flex: none; width: calc(var(--frame) - 10px); margin-right: 10px; }
.xr-tdm-frame i { flex: 1; height: 16px; border-radius: 1px; background: var(--c); }
.xr-tdm-frame .xr-tdm-f { flex: none; width: 3px; background: #fff; box-shadow: 0 0 6px #fff; }
@keyframes xr-tdm-flow { from { transform: translateX(calc(-1 * var(--frame))); } to { transform: translateX(0); } }
.xr-tdm[data-timing=lof] .xr-tdm-frame i { background: #3a4a52; }
.xr-tdm[data-timing=lof] .xr-tdm-frame .xr-tdm-f { background: var(--tdm-bad); box-shadow: none; }
.xr-tdm[data-timing=lof] .xr-tdm-lane { border-color: #ff7b6b66; }
.xr-tdm .xr-tdm-math { margin: 12px 0 0; color: #cfe3ea; font: 400 13px/1.6 var(--mono); }
.xr-tdm .xr-tdm-math strong { color: #b3f4f8; }

.xr-tdm-clock { margin-top: 4px; }
.xr-tdm .xr-tdm-rate { margin: 0 0 10px; color: #cfe3ea; font: 400 14px/1.5 var(--sans); }
.xr-tdm .xr-tdm-rate strong { color: #e6f7fb; }
.xr-tdm-minute { position: relative; display: flex; justify-content: space-between; padding-top: 24px; color: #8fa9b6; font: 400 11px var(--mono); }
.xr-tdm-ticks { position: absolute; top: 0; left: 0; right: 0; height: 18px; border-radius: 4px; background: #72e5ef1a; border: 1px solid #35505d; }
.xr-tdm-ticks i { position: absolute; top: -1px; bottom: -1px; width: 2px; margin-left: -1px; background: var(--tdm-bad); }
.xr-tdm[data-timing=lof] .xr-tdm-ticks { background: repeating-linear-gradient(135deg, #ff7b6b40 0 6px, #ff7b6b1a 6px 12px); border-color: #ff7b6b66; }

.xr-tdm-outputs { display: grid; grid-template-columns: repeat(auto-fit, minmax(230px, 1fr)); gap: 8px; margin: 16px 0 0; padding: 0; list-style: none; }
.xr-tdm-outputs li { display: flex; gap: 10px; padding: 12px 14px; border: 1px solid #35505d; border-radius: 8px; background: #0d2631; }
.xr-tdm-outputs li[data-state=slips] { border-color: #f2b56b66; }
.xr-tdm-outputs li[data-state=lof] { border-color: #ff7b6b66; }
.xr-tdm-outputs .xr-tdm-swatch { margin-top: 4px; }
.xr-tdm-outputs strong { color: #e6f7fb; font: 600 14px/1.4 var(--sans); }
.xr-tdm-outputs .xr-tdm-slots-used { color: #8fa9b6; font: 400 11px var(--mono); }
.xr-tdm-outputs p { margin: 4px 0 0; color: #b9ced8; font: 400 13px/1.55 var(--sans); }

.xr-tdm-verdict { margin-top: 16px; padding: 14px 18px; border-left: 3px solid #72e5ef; border-radius: 0 8px 8px 0; background: #0d2631; color: #d9edf5; font: 400 14px/1.6 var(--sans); }
.xr-tdm-verdict[data-tone=warn] { border-color: #f2b56b; }
.xr-tdm-verdict[data-tone=bad] { border-color: #ff7b6b; }

@media (max-width: 699px) {
  .xr-tdm-slots { grid-template-columns: repeat(6, minmax(0, 1fr)); }
  .xr-tdm-track { --frame: 150px; }
}
.xr-tdm .xr-tdm-minute-label { margin: 0 0 6px; color: #8fa9b6; font: 400 12px/1.5 var(--sans); }
.xr-tdm .xr-tdm-help strong { color: #e6f7fb; }

/* Step 2: frames vs packets toggle and the comparison table. */
.xr-tdm-mode { display: inline-flex; margin: 4px 0 2px; padding: 3px; border: 1px solid #35505d; border-radius: 999px; background: #0a1d27; }
.xr-tdm-mode button { min-height: 36px; padding: 0 16px; border: 0; border-radius: 999px; background: none; color: #9bb5c3; font: 500 13px/1 var(--sans); cursor: pointer; }
.xr-tdm-mode button[aria-pressed=true] { background: #1b3b48; color: #e6f7fb; box-shadow: inset 0 0 0 1px #72e5ef88; }
.xr-tdm-mode button:focus-visible { outline: 2px solid #72e5ef; outline-offset: 2px; }
.xr-tdm-pkt { display: flex; flex-direction: row-reverse; gap: 1px; flex: none; }
.xr-tdm-pkt i { height: 16px; border-radius: 1px; background: var(--c); }
.xr-tdm-pkt .xr-tdm-h { width: 5px; background: #9fb3bd; }
.xr-tdm[data-mode=packets] .xr-tdm-end { color: #b3cdd7; }

.xr-tdm-compare { width: 100%; margin: 18px 0 0; border-collapse: collapse; font: 400 13px/1.5 var(--sans); }
.xr-tdm-compare caption { margin-bottom: 8px; text-align: left; }
.xr-tdm-compare th, .xr-tdm-compare td { padding: 8px 10px; border-bottom: 1px solid #1d3742; text-align: left; vertical-align: top; }
.xr-tdm-compare thead th { color: #e6f7fb; font-weight: 600; }
.xr-tdm-compare tbody th { color: #8fa9b6; font: 500 11px/1.5 var(--mono); letter-spacing: .04em; text-transform: uppercase; white-space: nowrap; }
.xr-tdm-compare td { color: #b9ced8; }

/* Step 3: clock-source cards and the fault switch. */
.xr-tdm-sources { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 8px; margin: 14px 0 0; padding: 0; border: 0; min-width: 0; }
.xr-tdm-sources legend { margin-bottom: 8px; padding: 0; color: #e6f7fb; font: 500 13px/1.4 var(--sans); }
.xr-tdm-source { --tone: #72e5ef; position: relative; display: flex; flex-direction: column; gap: 4px; padding: 12px 14px; border: 1px solid #35505d; border-radius: 8px; background: #0d2631; cursor: pointer; }
.xr-tdm-source[data-tone=stratum3] { --tone: #f2b56b; }
.xr-tdm-source[data-tone=stratum4] { --tone: #ff7b6b; }
.xr-tdm-source input { position: absolute; opacity: 0; pointer-events: none; }
.xr-tdm-source-name { display: flex; align-items: center; gap: 8px; color: #e6f7fb; font: 600 14px/1.3 var(--sans); }
.xr-tdm-source-name::before { content: ''; flex: none; width: 12px; height: 12px; border: 2px solid #5d7c89; border-radius: 50%; }
.xr-tdm-source-copy { color: #9bb5c3; font: 400 12.5px/1.45 var(--sans); }
.xr-tdm-source-spec { margin-top: auto; padding-top: 4px; color: var(--tone); font: 500 11px/1.4 var(--mono); }
.xr-tdm-source:hover { border-color: #5d7c89; }
.xr-tdm-source:has(input:checked) { border-color: var(--tone); background: color-mix(in srgb, var(--tone) 9%, #0d2631); }
.xr-tdm-source:has(input:checked) .xr-tdm-source-name::before { border-color: var(--tone); background: radial-gradient(circle, var(--tone) 0 3px, transparent 3.5px); }
.xr-tdm-source:has(input:focus-visible) { outline: 2px solid #72e5ef; outline-offset: 2px; }
.xr-tdm-sources:disabled { opacity: .45; }
.xr-tdm-sources:disabled .xr-tdm-source { cursor: not-allowed; }

.xr-tdm-fault { display: flex; align-items: center; gap: 12px; margin: 12px 0 18px; padding: 10px 14px; border: 1px dashed #ff7b6b55; border-radius: 8px; cursor: pointer; }
.xr-tdm-fault input { position: absolute; opacity: 0; pointer-events: none; }
.xr-tdm-fault-switch { position: relative; flex: none; width: 36px; height: 20px; border-radius: 999px; background: #22343c; box-shadow: inset 0 0 0 1px #4a6977; transition: background .2s; }
.xr-tdm-fault-switch::after { content: ''; position: absolute; top: 3px; left: 3px; width: 14px; height: 14px; border-radius: 50%; background: #9bb5c3; transition: transform .2s; }
.xr-tdm-fault input:checked + .xr-tdm-fault-switch { background: #ff7b6b55; box-shadow: inset 0 0 0 1px #ff7b6b; }
.xr-tdm-fault input:checked + .xr-tdm-fault-switch::after { transform: translateX(16px); background: #ff7b6b; }
.xr-tdm-fault input:focus-visible + .xr-tdm-fault-switch { outline: 2px solid #72e5ef; outline-offset: 2px; }
.xr-tdm-fault strong { display: block; color: #e6f7fb; font: 600 14px/1.3 var(--sans); }
.xr-tdm-fault small { color: #9bb5c3; font: 400 12.5px/1.4 var(--sans); }
.xr-tdm .xr-tdm-rate strong { font-size: 17px; }
.xr-tdm-help em { color: #e6f7fb; }

@media (max-width: 699px) {
  .xr-tdm-sources { grid-template-columns: 1fr; }
  .xr-tdm-compare { font-size: 12.5px; }
  .xr-tdm-compare th, .xr-tdm-compare td { padding: 7px 6px; }
  .xr-tdm-compare tbody th { white-space: normal; }
}
@media (prefers-reduced-motion: reduce) {
  .xr-tdm-fault-switch, .xr-tdm-fault-switch::after { transition: none; }
}