.rt-shell {
  min-height: 100vh;
  box-sizing: border-box;

  padding: 28px 18px 70px;

  background:
    radial-gradient(
      circle at 50% 0%,
      rgba(255, 255, 255, 0.055),
      transparent 30%
    ),
    #000;

  color: #fff;
}


/* HEADER */

.rt-header {
  width: min(94vw, 1100px);
  margin: 0 auto;

  text-align: center;
}

.rt-logo {
  display: block;

  width: min(22vw, 190px);
  height: auto;

  margin: 0 auto;
}

.rt-eyebrow {
  margin-top: 22px;

  color: #777;

  font-size: 11px;
  font-weight: 700;

  letter-spacing: 3px;
}

.rt-header h1 {
  margin: 8px 0 0;

  font-size: clamp(34px, 5vw, 58px);
  font-weight: 700;

  letter-spacing: -1px;
}

.rt-tagline {
  margin: 12px 0 0;

  font-size: clamp(17px, 2.2vw, 23px);
  font-weight: 700;
}

.rt-intro {
  max-width: 720px;

  margin: 16px auto 0;

  color: #aaa;

  font-size: 15px;
  line-height: 1.6;
}


/* WORKSPACE */

.rt-workspace {
  width: min(94vw, 1100px);

  margin: 48px auto 0;

  display: grid;
  grid-template-columns: 1fr 1fr;

  gap: 18px;
}

.rt-panel {
  overflow: hidden;

  border: 1px solid #343434;
  border-radius: 16px;

  background:
    linear-gradient(
      145deg,
      #111,
      #080808
    );
}

.rt-panel-title {
  padding: 18px 22px;

  border-bottom: 1px solid #2a2a2a;

  color: #ddd;

  font-size: 13px;
  font-weight: 700;

  letter-spacing: 1.5px;
  text-transform: uppercase;
}


/* DIAGRAM */

.rt-diagram-wrap {
  min-height: 420px;

  display: flex;
  align-items: center;
  justify-content: center;

  padding: 20px;

  box-sizing: border-box;
}

.rt-diagram {
  width: 100%;
  height: auto;
}

.rt-diagram line,
.rt-diagram path {
  fill: none;

  stroke: #ddd;
  stroke-width: 2.2;

  vector-effect: non-scaling-stroke;
}

.rt-diagram text {
  fill: #aaa;

  font-family: Arial, Helvetica, sans-serif;
  font-size: 17px;
  font-weight: 700;

  letter-spacing: 0.4px;
}

.rt-diagram .angle-text {
  font-size: 23px;
}

.rt-diagram-note {
  padding: 0 22px 20px;

  color: #666;

  font-size: 12px;
  text-align: center;
}


/* INPUT */

.rt-input-panel {
  padding-bottom: 22px;
}

.rt-help {
  margin: 20px 22px 0;

  color: #888;

  font-size: 13px;
  line-height: 1.5;
}

.rt-field-legend {
  margin: 12px 22px 0;

  display: flex;
  gap: 18px;

  color: #777;

  font-size: 11px;
}

.rt-field-legend span {
  display: flex;
  align-items: center;
  gap: 7px;
}

.rt-legend-box {
  width: 12px;
  height: 12px;

  box-sizing: border-box;

  border-radius: 3px;
}

.rt-legend-box.entered {
  border: 1px solid #8a8a8a;
  background: #111;
}

.rt-legend-box.calculated {
  border: 1px solid #3a3a3a;
  background: #080808;
}

.rt-input-grid {
  padding: 20px 22px 0;

  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));

  gap: 15px;
}

.rt-field {
  display: block;
}

.rt-field > span {
  display: block;

  margin-bottom: 7px;

  color: #aaa;

  font-size: 12px;
  font-weight: 700;
}

.rt-field input {
  width: 100%;

  box-sizing: border-box;

  padding: 12px 13px;

  border: 1px solid #3c3c3c;
  border-radius: 8px;

  outline: none;

  background: #050505;
  color: #fff;

  font-size: 18px;

  transition:
    border-color 0.2s ease,
    background 0.2s ease;
}

.rt-field input:focus {
  border-color: #888;
  background: #0a0a0a;
}

/*
 * Field state indicators
 */

.rt-field input.rt-entered-value {
  border-color: #8a8a8a;
  background: #111;
}

.rt-field input.rt-calculated-value {
  border-color: #3a3a3a;
  background: #080808;
  color: #c8c8c8;
}

.rt-field input.rt-entered-value:focus,
.rt-field input.rt-calculated-value:focus {
  border-color: #aaa;
}

.rt-input-with-unit {
  position: relative;
}

.rt-input-with-unit input {
  padding-right: 44px;
}

.rt-input-with-unit span {
  position: absolute;

  right: 14px;
  top: 50%;

  transform: translateY(-50%);

  color: #777;

  font-size: 15px;
}

.rt-pitch-row {
  display: grid;
  grid-template-columns: 1fr auto 60px;

  gap: 9px;

  align-items: center;
}

.rt-pitch-mark {
  color: #777;

  font-size: 20px;
  font-weight: 700;
}

.rt-pitch-fixed {
  padding: 12px 10px;

  border: 1px solid #333;
  border-radius: 8px;

  background: #0b0b0b;

  color: #888;

  text-align: center;
  font-size: 18px;
}


/* BUTTONS */

.rt-actions {
  padding: 22px 22px 0;

  display: flex;

  gap: 10px;
}

.rt-primary-button,
.rt-secondary-button {
  min-height: 45px;

  padding: 11px 18px;

  border-radius: 8px;

  font-size: 14px;
  font-weight: 700;

  cursor: pointer;
}

.rt-primary-button {
  flex: 1;

  border: 1px solid #fff;

  background: #fff;
  color: #000;
}

.rt-primary-button:hover {
  background: #ddd;
}

.rt-secondary-button {
  border: 1px solid #555;

  background: transparent;
  color: #fff;
}

.rt-secondary-button:hover {
  background: #141414;
}

.rt-status {
  min-height: 20px;

  margin: 14px 22px 0;

  color: #aaa;

  font-size: 13px;
  line-height: 1.4;
}


/* SECTION HEADINGS */

.rt-results-section,
.rt-solution,
.rt-learning {
  width: min(94vw, 1100px);

  margin: 52px auto 0;
}

.rt-section-heading {
  display: flex;

  gap: 14px;

  align-items: flex-start;
}

.rt-section-number {
  min-width: 30px;

  color: #555;

  font-size: 11px;
  font-weight: 700;

  letter-spacing: 2px;
}

.rt-section-heading h2 {
  margin: 0;

  font-size: 27px;
}

.rt-section-heading p {
  margin: 7px 0 0;

  color: #888;

  font-size: 14px;
}


/* RESULTS */

.rt-results-grid {
  margin-top: 22px;

  display: grid;
  grid-template-columns: repeat(4, 1fr);

  gap: 12px;
}

.rt-result-card {
  min-height: 95px;

  box-sizing: border-box;

  padding: 16px;

  border: 1px solid #303030;
  border-radius: 12px;

  background: #0b0b0b;
}

.rt-result-card span {
  display: block;

  color: #777;

  font-size: 11px;
  font-weight: 700;
}

.rt-result-card strong {
  display: block;

  margin-top: 9px;

  color: #fff;

  font-size: 21px;
  font-weight: 700;
}

/* YOUR SOLUTION */

.rt-solution-card {
  margin-top: 22px;

  padding: 24px;

  border: 1px solid #303030;
  border-radius: 14px;

  background:
    linear-gradient(
      145deg,
      #101010,
      #080808
    );
}

.rt-solution-placeholder {
  margin: 0;

  color: #777;

  font-size: 14px;
  line-height: 1.6;
}

.rt-solution-entered {
  margin-bottom: 20px;

  padding-bottom: 16px;

  border-bottom: 1px solid #2d2d2d;

  color: #bbb;

  font-size: 14px;
}

.rt-step {
  margin-top: 18px;
}

.rt-step:first-of-type {
  margin-top: 0;
}

.rt-step-number {
  color: #666;

  font-size: 11px;
  font-weight: 700;

  letter-spacing: 1.5px;
}

.rt-step-title {
  margin-top: 4px;

  color: #fff;

  font-size: 16px;
  font-weight: 700;
}

.rt-step-formula {
  margin-top: 7px;

  color: #ccc;

  font-family: Consolas, monospace;
  font-size: 15px;
  line-height: 1.5;
}

.rt-step-note {
  margin-top: 5px;

  color: #777;

  font-size: 13px;
  line-height: 1.5;
}

/* LEARNING */

.rt-learning-grid {
  margin-top: 22px;

  display: grid;
  grid-template-columns: repeat(2, 1fr);

  gap: 14px;
}

.rt-learning-card {
  padding: 22px;

  border: 1px solid #303030;
  border-radius: 14px;

  background:
    linear-gradient(
      145deg,
      #101010,
      #080808
    );
}

.rt-formula {
  display: inline-block;

  margin-bottom: 16px;
  padding: 8px 10px;

  border: 1px solid #3b3b3b;
  border-radius: 7px;

  background: #050505;

  color: #ddd;

  font-family: Consolas, monospace;
  font-size: 16px;
}

.rt-learning-card h3 {
  margin: 0;

  font-size: 18px;
}

.rt-learning-card p {
  margin: 10px 0 0;

  color: #888;

  font-size: 14px;
  line-height: 1.55;
}


/* BOTTOM NAV */

.rt-bottom-nav {
  margin-top: 42px;

  text-align: center;
}

.rt-back-button {
  display: inline-block;

  padding: 11px 17px;

  border: 1px solid #555;
  border-radius: 8px;

  color: #fff;

  font-size: 14px;
  text-decoration: none;
}

.rt-back-button:hover {
  background: #151515;
  border-color: #888;
}


/* RESPONSIVE */

@media (max-width: 850px) {

  .rt-workspace {
    grid-template-columns: 1fr;
  }

  .rt-results-grid {
    grid-template-columns: repeat(2, 1fr);
  }

}


@media (max-width: 600px) {

  .rt-shell {
    padding-left: 12px;
    padding-right: 12px;
  }

  .rt-input-grid {
    grid-template-columns: 1fr;
  }

  .rt-learning-grid {
    grid-template-columns: 1fr;
  }

  .rt-results-grid {
    grid-template-columns: 1fr 1fr;
  }

  .rt-diagram-wrap {
    min-height: 300px;
    padding: 10px;
  }

  .rt-actions {
    flex-direction: column;
  }

}


@media (max-width: 420px) {

  .rt-results-grid {
    grid-template-columns: 1fr;
  }

  .rt-header h1 {
    font-size: 34px;
  }

}