/* ============================================================
 * Neurotype Brand System
 * File: css/diagrams.css
 * Step lists, loop diagrams, and bridge diagrams
 *
 * Variants: step-list, loop-diagram, bridge-diagram
 * Classes:  .step-list, .step-item, .step-number,
 *           .loop-diagram, .loop-step, .loop-arrow,
 *           .loop-return,
 *           .bridge-diagram, .bridge-column, .bridge-center,
 *           .bridge-list
 * ========================================================== */


/* ==========================================================
 * Step List
 * Vertical sequence with a connecting line and numbered
 * circles. The line runs behind the step numbers using a
 * pseudo-element on the list container.
 * ========================================================== */

.step-list {
  position: relative;
  display: flex;
  flex-direction: column;
  gap: var(--space-6);
  padding-left: var(--space-7);
}

/* Connecting line */
.step-list::before {
  content: "";
  position: absolute;
  top: 0;
  bottom: 0;
  left: calc(var(--space-6) / 2);
  width: var(--stroke-width);
  background-color: var(--border);
}

.step-item {
  position: relative;
  font-family: var(--font-body);
  font-size: var(--text-body);
  color: var(--text-heading);
  line-height: 1.6;
}

.step-item p {
  color: var(--text-muted);
  margin-top: var(--space-1);
}

/* Numbered circle positioned over the connecting line */
.step-number {
  position: absolute;
  left: calc(var(--space-7) * -1);
  top: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  width: var(--space-6);
  height: var(--space-6);
  font-family: var(--font-numeric);
  font-size: var(--text-small);
  font-weight: 700;
  color: var(--text-on-accent);
  background-color: var(--neurotype-accent-primary);
  border-radius: var(--radius-pill);
}


/* ==========================================================
 * Loop Diagram
 * Horizontal flow of steps connected by arrow chevrons,
 * with an optional return arrow beneath.
 * ========================================================== */

.loop-diagram {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: var(--space-4);
}

.loop-step {
  display: flex;
  align-items: center;
  justify-content: center;
  padding: var(--space-3) var(--space-5);
  font-family: var(--font-body);
  font-size: var(--text-small);
  color: var(--text-heading);
  background-color: var(--bg-secondary);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
}

/* Arrow between steps. Uses an inline SVG chevron via
 * background-image encoded as a data URI. */
.loop-arrow {
  display: flex;
  align-items: center;
  justify-content: center;
  width: var(--space-5);
  height: var(--space-5);
  color: var(--text-muted);
}

.loop-arrow svg {
  width: var(--space-4);
  height: var(--space-4);
  stroke: currentColor;
  stroke-width: 1.5;
  fill: none;
  stroke-linecap: round;
  stroke-linejoin: round;
}

/* Return arrow beneath the loop, indicating repetition */
.loop-return {
  width: 100%;
  display: flex;
  align-items: center;
  justify-content: center;
  padding-top: var(--space-3);
  font-family: var(--font-body);
  font-size: var(--text-caption);
  color: var(--text-muted);
}


/* ==========================================================
 * Bridge Diagram
 * Three-column layout: two side columns connected through a
 * centre bridge element.
 * ========================================================== */

.bridge-diagram {
  display: grid;
  grid-template-columns: 1fr auto 1fr;
  gap: var(--space-5);
  align-items: start;
}

.bridge-column {
  display: flex;
  flex-direction: column;
  gap: var(--space-4);
  padding: var(--space-5);
  background-color: var(--bg-secondary);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
}

/* Centre connecting element between the two columns.
 * Uses pseudo-elements for horizontal connecting lines. */
.bridge-center {
  position: relative;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: var(--space-3);
  padding: var(--space-5) var(--space-4);
  align-self: center;
  font-family: var(--font-body);
  font-size: var(--text-caption);
  color: var(--text-muted);
}

.bridge-center::before,
.bridge-center::after {
  content: "";
  position: absolute;
  top: 50%;
  width: var(--space-5);
  height: var(--stroke-width);
  background-color: var(--border);
}

.bridge-center::before {
  right: 100%;
}

.bridge-center::after {
  left: 100%;
}

/* List within a bridge column */
.bridge-list {
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
  list-style: none;
  margin: 0;
  padding: 0;
  font-family: var(--font-body);
  font-size: var(--text-small);
  color: var(--text-secondary);
}

.bridge-list li {
  padding-left: var(--space-4);
  position: relative;
}

.bridge-list li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 50%;
  transform: translateY(-50%);
  width: var(--dot-md);
  height: var(--dot-md);
  background-color: var(--neurotype-accent-primary);
  border-radius: var(--radius-pill);
}