:root {
  --bg: #171e2e;
  --surface: #192639;
  --surface2: #1c2d46;
  --border: #213456;
  --border2: #2a486b;
  --text: #b2cde8;
  --text-bright: #dff0ff;
  --text-dim: #6080a2;
  --accent: #56c5f0;
  --accent-dim: rgba(86, 197, 240, 0.13);
  --accent-glow: rgba(86, 197, 240, 0.38);
  --ship-a: #ffb866;
  --ship-b: #66e5ff;
  --cable-ok: #50e8b2;
  --cable-warn: #f8d050;
  --cable-danger: #ff6868;
  --font-h: "Syncopate", sans-serif;
  --font-b: "Raleway", sans-serif;
  --font-m: "JetBrains Mono", "Space Mono", monospace;
}
*,
*::before,
*::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}
html {
  scroll-behavior: smooth;
  font-size: 21.5px;
}
body {
  font-family: var(--font-b);
  background: var(--bg);
  color: var(--text);
  min-height: 100vh;
  overflow-x: hidden;
  padding-bottom: 2rem;
}
body::before {
  content: "";
  position: fixed;
  inset: 0;
  background:
    radial-gradient(
      ellipse 70% 50% at 50% 0%,
      rgba(28, 58, 120, 0.35) 0%,
      transparent 70%
    ),
    radial-gradient(
      ellipse 40% 30% at 85% 80%,
      rgba(18, 38, 90, 0.2) 0%,
      transparent 60%
    );
  pointer-events: none;
  z-index: 0;
}

/* ── CONTAINER ── */
.container {
  position: relative;
  z-index: 1;
  max-width: 1600px;
  margin: 0 auto;
  padding: 0 1.25rem;
}

/* ── HEADER ── */
header {
  text-align: center;
  padding: 2rem 1rem 1.5rem;
  border-bottom: 1px solid var(--border);
  margin-bottom: 1.5rem;
}
.header-eyebrow {
  font-family: var(--font-m);
  font-size: 0.62rem;
  letter-spacing: 0.25em;
  color: var(--accent);
  text-transform: uppercase;
  margin-bottom: 0.7rem;
  opacity: 0.8;
}
h1 {
  font-family: var(--font-h);
  font-size: clamp(1.2rem, 3.2vw, 2rem);
  font-weight: 700;
  color: var(--text-bright);
  letter-spacing: 0.05em;
  text-transform: uppercase;
  line-height: 1.2;
  margin-bottom: 0.6rem;
}
.header-sub {
  font-weight: 300;
  font-size: 0.95rem;
  color: var(--text-dim);
  max-width: 660px;
  margin: 0 auto;
  line-height: 1.5;
}

/* ── GRID ── */
.grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1.25rem;
}
@media (min-width: 1060px) {
  .grid {
    grid-template-columns: 2.2fr 1fr;
  }
}
.left-col,
.right-col {
  display: flex;
  flex-direction: column;
  gap: 1.25rem;
  min-width: 0;
}

/* ── PANEL ── */
.panel {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 1.1rem 1.25rem;
  box-shadow: 0 8px 36px rgba(0, 0, 0, 0.38);
  position: relative;
  overflow: visible;
}
.panel-title {
  font-family: var(--font-h);
  font-size: 0.58rem;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--accent);
  margin-bottom: 0.9rem;
  display: flex;
  align-items: center;
  gap: 0.5rem;
}
.panel-title::before {
  content: "";
  display: inline-block;
  width: 3px;
  height: 12px;
  background: var(--accent);
  border-radius: 2px;
  flex-shrink: 0;
}

/* ── VIEW TABS ── */
.view-tabs {
  display: flex;
  gap: 0.4rem;
  margin-bottom: 0.65rem;
  justify-content: center;   /* ← centered */
}
.view-tab {
  font-family: var(--font-m);
  font-size: 0.62rem;
  letter-spacing: 0.08em;
  padding: 0.3rem 0.8rem;
  border-radius: 5px;
  border: 1px solid var(--border2);
  background: transparent;
  color: var(--text-dim);
  cursor: pointer;
  transition: all 0.18s;
}
.view-tab:hover {
  color: var(--text);
  border-color: var(--text-dim);
}
.view-tab.active {
  background: var(--accent-dim);
  border-color: var(--accent);
  color: var(--accent);
}

/* ── CANVAS ── */
.canvas-wrap {
  position: relative;
  border-radius: 8px;
  border: 1px solid var(--border);
  background: #0a1018;
  overflow: visible;
}
canvas {
  display: block;
  width: 100%;
  border-radius: 8px;
}
.canvas-badge {
  position: absolute;
  top: 0.65rem;
  right: 0.65rem;
  background: rgba(12, 22, 42, 0.88);
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
  border: 1px solid var(--border2);
  border-radius: 6px;
  padding: 0.35rem 0.65rem;
  font-family: var(--font-m);
  font-size: 0.62rem;
  color: var(--text-dim);
  pointer-events: none;
  line-height: 1.7;
}
.canvas-badge span {
  color: var(--text-bright);
}
.scenario-badge {
  position: absolute;
  top: 0.65rem;
  left: 0.65rem;
  border-radius: 5px;
  padding: 0.25rem 0.55rem;
  font-family: var(--font-m);
  font-size: 0.58rem;
  letter-spacing: 0.08em;
  font-weight: 700;
  text-transform: uppercase;
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
  pointer-events: none;
}
.sb-bell {
  background: rgba(255, 184, 102, 0.15);
  border: 1px solid rgba(255, 184, 102, 0.4);
  color: var(--ship-a);
}
.sb-tow {
  background: rgba(102, 229, 255, 0.12);
  border: 1px solid rgba(102, 229, 255, 0.4);
  color: var(--ship-b);
}

/* ── CONTROLS GRID ── */
.controls-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 0.85rem 1.4rem;
  margin-bottom: 0.85rem;
}
@media (min-width: 500px) {
  .controls-grid {
    grid-template-columns: repeat(4, 1fr);
  }
}
.ctrl-row {
  display: flex;
  flex-direction: column;
  gap: 0.3rem;
}
.ctrl-label {
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-size: 0.68rem;
  font-weight: 600;
  color: var(--text-dim);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  flex-wrap: nowrap;
  gap: 0.3rem;
}
.ctrl-name {
  display: flex;
  align-items: center;
  gap: 0.25rem;
  white-space: nowrap;
  flex-shrink: 0;
}
.ctrl-val {
  font-family: var(--font-m);
  font-size: 0.68rem;
  color: var(--accent);
  white-space: nowrap;
  flex-shrink: 0;
}

/* Range sliders */
input[type="range"] {
  -webkit-appearance: none;
  width: 100%;
  height: 22px;
  background: transparent;
  cursor: pointer;
}
input[type="range"]:focus {
  outline: none;
}
input[type="range"]::-webkit-slider-runnable-track {
  width: 100%;
  height: 4px;
  background: var(--border2);
  border-radius: 2px;
}
input[type="range"]:hover::-webkit-slider-runnable-track {
  background: #2a5090;
}
input[type="range"]::-webkit-slider-thumb {
  -webkit-appearance: none;
  width: 13px;
  height: 13px;
  border-radius: 50%;
  background: var(--accent);
  margin-top: -4.5px;
  box-shadow: 0 0 7px rgba(86, 197, 240, 0.55);
  transition:
    transform 0.1s,
    box-shadow 0.1s;
}
input[type="range"]::-webkit-slider-thumb:hover {
  transform: scale(1.25);
  box-shadow: 0 0 12px rgba(86, 197, 240, 0.75);
}
input[type="range"]::-moz-range-track {
  height: 4px;
  background: var(--border2);
  border-radius: 2px;
}
input[type="range"]::-moz-range-thumb {
  width: 13px;
  height: 13px;
  border-radius: 50%;
  background: var(--accent);
  border: none;
}

/* ── ROPE LENGTH SELECTOR ── */
.rope-length-row {
  display: none;
  margin-top: 0.85rem;
  padding: 0.65rem 0.85rem 0.7rem;
  background: rgba(255, 184, 102, 0.04);
  border: 1px solid rgba(255, 184, 102, 0.2);
  border-radius: 8px;
}
.rope-length-row.visible {
  display: block;
}
.rope-length-btns {
  display: flex;
  gap: 0.45rem;
  margin-top: 0.5rem;
}
.rope-btn {
  font-family: var(--font-m);
  font-size: 0.58rem;
  letter-spacing: 0.04em;
  padding: 0.35rem 0.6rem;
  border-radius: 5px;
  border: 1px solid var(--border2);
  background: transparent;
  color: var(--text-dim);
  cursor: pointer;
  transition: all 0.15s;
  flex: 1;
  text-align: center;
  line-height: 1.4;
}
.rope-btn:hover {
  border-color: var(--ship-a);
  color: var(--ship-a);
  background: rgba(255, 184, 102, 0.06);
}
.rope-btn.active {
  background: rgba(255, 184, 102, 0.12);
  border-color: var(--ship-a);
  color: var(--ship-a);
}
.rope-btn-sub {
  display: block;
  font-size: 0.52rem;
  opacity: 0.65;
  letter-spacing: 0.02em;
}

/* ── PLAYBACK BAR ── */
.playback-bar {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  flex-wrap: wrap;
  padding-top: 0.75rem;
  border-top: 1px solid var(--border);
}
.btn {
  font-family: var(--font-m);
  font-size: 0.62rem;
  letter-spacing: 0.07em;
  padding: 0.42rem 1rem;
  border-radius: 5px;
  border: 1px solid var(--border2);
  background: var(--surface2);
  color: var(--text);
  cursor: pointer;
  transition: all 0.15s;
  white-space: nowrap;
}
.btn:hover {
  border-color: var(--accent);
  color: var(--accent);
}
.btn.primary {
  background: var(--accent);
  border-color: var(--accent);
  color: #050e1c;
  font-weight: 700;
}
.btn.primary:hover {
  background: #80d8f8;
  border-color: #80d8f8;
}
.speed-group {
  display: flex;
  align-items: center;
  gap: 0.3rem;
  margin-left: auto;
  flex-wrap: wrap;
}
.speed-label {
  font-size: 0.62rem;
  color: var(--text-dim);
  font-family: var(--font-m);
}
.speed-btn {
  font-family: var(--font-m);
  font-size: 0.6rem;
  padding: 0.22rem 0.48rem;
  border-radius: 4px;
  border: 1px solid var(--border2);
  background: transparent;
  color: var(--text-dim);
  cursor: pointer;
  transition: all 0.15s;
}
.speed-btn:hover,
.speed-btn.active {
  border-color: var(--accent);
  color: var(--accent);
  background: var(--accent-dim);
}

/* ── SCENARIO SELECTOR ── */
.scenario-section {
  margin-top: 0.85rem;
  padding-top: 0.75rem;
  border-top: 1px solid var(--border);
}
.scenario-section-title {
  font-family: var(--font-h);
  font-size: 0.52rem;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--text-dim);
  margin-bottom: 0.6rem;
}
.scenario-cards {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 0.6rem;
}
.scenario-card {
  display: block;
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 0.7rem 0.85rem;
  cursor: pointer;
  transition: all 0.18s;
  background: rgba(0, 0, 0, 0.12);
}
.scenario-card input[type="radio"] {
  position: absolute;
  opacity: 0;
  pointer-events: none;
}
.scenario-card:hover {
  border-color: var(--border2);
  background: rgba(255, 255, 255, 0.03);
}
.active-bell {
  border-color: rgba(255, 184, 102, 0.45);
  background: rgba(255, 184, 102, 0.06);
}
.active-tow {
  border-color: rgba(102, 229, 255, 0.4);
  background: rgba(102, 229, 255, 0.05);
}
.sc-header {
  display: flex;
  align-items: center;
  gap: 0.45rem;
  margin-bottom: 0.35rem;
}
.sc-dot {
  width: 7px;
  height: 7px;
  border-radius: 50%;
  background: var(--text-dim);
  flex-shrink: 0;
  transition: background 0.2s;
}
.active-bell .sc-dot {
  background: var(--ship-a);
}
.active-tow .sc-dot {
  background: var(--ship-b);
}
.sc-name {
  font-family: var(--font-m);
  font-size: 0.62rem;
  font-weight: 700;
  color: var(--text);
  transition: color 0.2s;
}
.active-bell .sc-name {
  color: var(--ship-a);
}
.active-tow .sc-name {
  color: var(--ship-b);
}
.sc-desc {
  font-size: 0.7rem;
  color: var(--text-dim);
  line-height: 1.45;
}

/* ── ATTACHMENT CONFIGS ── */
.attach-configs {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 0.85rem;
  margin-top: 0.75rem;
  padding-top: 0.7rem;
  border-top: 1px solid var(--border);
}
.ship-card {
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 0.75rem;
  background: rgba(0, 0, 0, 0.15);
}
.ship-card-title {
  font-family: var(--font-m);
  font-size: 0.62rem;
  font-weight: 700;
  letter-spacing: 0.1em;
  margin-bottom: 0.55rem;
}
.ship-a-title {
  color: var(--ship-a);
}
.ship-b-title {
  color: var(--ship-b);
}
.cfg-row {
  margin-bottom: 0;
}
.cfg-row label {
  display: block;
  font-size: 0.66rem;
  color: var(--text-dim);
  margin-bottom: 0.22rem;
  letter-spacing: 0.03em;
}
select {
  width: 100%;
  background: var(--bg);
  color: var(--text-bright);
  border: 1px solid var(--border2);
  border-radius: 4px;
  padding: 0.3rem 0.45rem;
  font-family: var(--font-b);
  font-size: 0.78rem;
  cursor: pointer;
  outline: none;
  transition: border-color 0.15s;
}
select:hover,
select:focus {
  border-color: var(--accent);
}

/* ── EQUATIONS ── */
.eq-table-wrap {
  overflow-x: visible;
}
.eq-table {
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 0.44rem 0.85rem;
  align-items: center;
}
.eq-row-label {
  font-size: 0.74rem;
  color: var(--text-dim);
  display: flex;
  align-items: center;
  gap: 0.4rem;
  flex-wrap: wrap;
  transition: opacity 0.3s;
}
.eq-formula {
  font-family: var(--font-m);
  font-size: 0.6rem;
  color: #38567a;
}
.eq-result {
  font-family: var(--font-m);
  font-size: 0.78rem;
  font-weight: 700;
  color: var(--text-bright);
  text-align: right;
  white-space: nowrap;
  transition: opacity 0.3s;
}
.eq-result.v-color {
  color: var(--accent);
}
.eq-result.cable-color {
  color: var(--ship-a);
}
.eq-result.tow-color {
  color: var(--ship-b);
}
.eq-result.big {
  font-size: 0.95rem;
}
.eq-divider {
  grid-column: 1/-1;
  height: 1px;
  background: var(--border);
  margin: 0.18rem 0;
}
.eq-scenario-tag {
  font-family: var(--font-m);
  font-size: 0.55rem;
  padding: 0.12rem 0.4rem;
  border-radius: 3px;
  display: inline-block;
}
.tag-bell {
  background: rgba(255, 184, 102, 0.12);
  color: var(--ship-a);
  border: 1px solid rgba(255, 184, 102, 0.3);
}
.tag-tow {
  background: rgba(102, 229, 255, 0.1);
  color: var(--ship-b);
  border: 1px solid rgba(102, 229, 255, 0.3);
}

/* Equation dimming when switching frames */
.eq-dimmed {
  opacity: 0.22 !important;
}

/* Key insight box */
.insight-box {
  margin-top: 0.9rem;
  background: rgba(86, 197, 240, 0.05);
  border: 1px solid rgba(86, 197, 240, 0.18);
  border-radius: 8px;
  padding: 0.75rem 0.9rem;
}
.insight-title {
  font-family: var(--font-m);
  font-size: 0.6rem;
  letter-spacing: 0.12em;
  color: var(--accent);
  margin-bottom: 0.35rem;
  text-transform: uppercase;
}
.insight-eq {
  font-family: var(--font-m);
  font-size: 0.8rem;
  color: var(--text-bright);
  margin-bottom: 0.45rem;
}

/* Insight capsule (details/summary) */
.insight-capsule {
  margin-top: 0.3rem;
}
.insight-capsule summary {
  display: inline-flex;
  align-items: center;
  gap: 0.3rem;
  font-family: var(--font-m);
  font-size: 0.56rem;
  letter-spacing: 0.08em;
  color: var(--accent);
  cursor: pointer;
  padding: 0.2rem 0.55rem;
  border: 1px solid rgba(86, 197, 240, 0.28);
  border-radius: 4px;
  background: rgba(86, 197, 240, 0.07);
  list-style: none;
  transition: background 0.15s, border-color 0.15s;
  user-select: none;
}
.insight-capsule summary::-webkit-details-marker {
  display: none;
}
.insight-capsule summary:hover {
  background: rgba(86, 197, 240, 0.14);
  border-color: rgba(86, 197, 240, 0.5);
}
.insight-capsule[open] summary {
  border-color: var(--accent);
  background: rgba(86, 197, 240, 0.12);
}
.insight-sub {
  font-size: 0.74rem;
  color: var(--text-dim);
  line-height: 1.55;
  margin-top: 0.5rem;
  padding-top: 0.45rem;
  border-top: 1px solid rgba(86, 197, 240, 0.1);
}

/* ── STRAIN MONITOR ── */
.strain-top {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  margin-bottom: 0.7rem;
  gap: 0.5rem;
  flex-wrap: wrap;
}
.strain-values {
  display: flex;
  gap: 1.25rem;
  flex-wrap: wrap;
}
.sv-item {
  display: flex;
  flex-direction: column;
  gap: 0.1rem;
}
.sv-label {
  font-size: 0.6rem;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--text-dim);
}
.sv-num {
  font-family: var(--font-m);
  font-size: 0.88rem;
  font-weight: 700;
  color: var(--text-bright);
  transition: color 0.3s;
}
.strain-bar-bg {
  height: 10px;
  background: rgba(0, 0, 0, 0.35);
  border-radius: 5px;
  overflow: hidden;
  border: 1px solid var(--border);
  position: relative;
}
.strain-bar-fill {
  height: 100%;
  width: 0%;
  border-radius: 5px;
  transition:
    width 0.1s linear,
    background-color 0.3s;
}
.status-badge {
  display: inline-flex;
  align-items: center;
  gap: 0.3rem;
  font-family: var(--font-m);
  font-size: 0.6rem;
  letter-spacing: 0.12em;
  font-weight: 700;
  padding: 0.22rem 0.55rem;
  border-radius: 4px;
  text-transform: uppercase;
  white-space: nowrap;
}
.status-badge::before {
  content: "";
  display: block;
  width: 5px;
  height: 5px;
  border-radius: 50%;
}
.s-intact {
  background: rgba(80, 232, 178, 0.1);
  color: var(--cable-ok);
  border: 1px solid rgba(80, 232, 178, 0.3);
}
.s-intact::before {
  background: var(--cable-ok);
}
.s-slack {
  background: rgba(196, 156, 100, 0.1);
  color: #c49c64;
  border: 1px solid rgba(196, 156, 100, 0.3);
}
.s-slack::before {
  background: #c49c64;
}
.s-tension {
  background: rgba(248, 208, 80, 0.1);
  color: var(--cable-warn);
  border: 1px solid rgba(248, 208, 80, 0.3);
}
.s-tension::before {
  background: var(--cable-warn);
}
.s-broken {
  background: rgba(255, 104, 104, 0.1);
  color: var(--cable-danger);
  border: 1px solid rgba(255, 104, 104, 0.3);
  animation: pulse-red 1s infinite;
}
.s-broken::before {
  background: var(--cable-danger);
}
.s-tow {
  background: rgba(102, 229, 255, 0.1);
  color: var(--ship-b);
  border: 1px solid rgba(102, 229, 255, 0.3);
}
.s-tow::before {
  background: var(--ship-b);
}
@keyframes pulse-red {
  0%,
  100% {
    opacity: 1;
  }
  50% {
    opacity: 0.5;
  }
}

/* Tow mode tension display */
.tow-tension-row {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-top: 0.55rem;
  padding-top: 0.55rem;
  border-top: 1px solid var(--border);
}
.tow-tension-label {
  font-size: 0.68rem;
  color: var(--text-dim);
}
.tow-tension-val {
  font-family: var(--font-m);
  font-size: 0.8rem;
  color: var(--ship-b);
  font-weight: 700;
}

/* ── TOOLTIP ── */
.info-wrap {
  position: relative;
  display: inline-flex;
  align-items: center;
}
.info-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 14px;
  height: 14px;
  border-radius: 50%;
  background: rgba(86, 197, 240, 0.12);
  border: 1px solid rgba(86, 197, 240, 0.35);
  color: var(--accent);
  font-size: 0.55rem;
  cursor: default;
  margin-left: 0.25rem;
  font-family: var(--font-m);
  flex-shrink: 0;
  transition: background 0.15s;
}
.info-btn:hover {
  background: rgba(86, 197, 240, 0.22);
}
.info-tip {
  position: absolute;
  bottom: calc(100% + 8px);
  left: 50%;
  transform: translateX(-50%);
  background: #0e1e38;
  border: 1px solid var(--border2);
  border-radius: 6px;
  padding: 0.55rem 0.75rem;
  font-size: 0.72rem;
  color: var(--text);
  line-height: 1.5;
  width: 280px;
  box-shadow: 0 6px 24px rgba(0, 0, 0, 0.55);
  z-index: 9999;
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.15s;
  white-space: normal;
}
.info-tip::after {
  content: "";
  position: absolute;
  top: 100%;
  left: 50%;
  transform: translateX(-50%);
  border: 5px solid transparent;
  border-top-color: var(--border2);
}
.info-wrap:hover .info-tip {
  opacity: 1;
}

/* ── EXPLANATION ── */
.expl-body p {
  font-size: 0.86rem;
  color: var(--text-dim);
  line-height: 1.72;
  margin-bottom: 0.9rem;
}
.expl-body p:last-child {
  margin-bottom: 0;
}
.expl-body strong {
  color: var(--text);
  font-weight: 600;
}
.callout {
  background: rgba(255, 184, 102, 0.06);
  border-left: 3px solid var(--ship-a);
  border-radius: 0 6px 6px 0;
  padding: 0.65rem 0.9rem;
  margin: 0.75rem 0;
  font-size: 0.82rem;
  color: var(--text);
  line-height: 1.6;
}
.callout-b {
  background: rgba(102, 229, 255, 0.05);
  border-left: 3px solid var(--ship-b);
}
.callout-g {
  background: rgba(80, 232, 178, 0.05);
  border-left: 3px solid var(--cable-ok);
}

/* ── RESPONSIVE ── */
@media (max-width: 540px) {
  .container {
    padding: 0 0.75rem;
  }
  h1 {
    font-size: 1.1rem;
  }
  .controls-grid {
    grid-template-columns: 1fr 1fr;
  }
  .scenario-cards,
  .attach-configs {
    grid-template-columns: 1fr;
  }
  .speed-group {
    margin-left: 0;
  }
  .rope-length-btns {
    flex-direction: column;
  }
}