/* Task Dependency Critical Path Scheduler - vis-network-tutorial layout
 * =====================================================================
 * Wide (>= 720px): dependency graph on the left, question panel on the right.
 * Narrow (< 720px): title, graph, and question panel stacked and scrolled together.
 * The whole page fits inside the iframe height (CANVAS_HEIGHT + 2);
 * the graph area absorbs any spare height so nothing scrolls.
 *
 * Colors are from the Okabe-Ito color-blind-safe palette (blue / orange).
 * Critical tasks also carry a star and the word "critical", a thick border,
 * and thick solid arrows, so meaning never depends on color alone.
 */

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html, body {
    height: 100%;
    overflow: hidden;
}

body {
    font-family: Arial, Helvetica, sans-serif;
    background-color: aliceblue;
    color: #1a1a1a;
    font-size: 16px;
}

.container {
    display: flex;
    flex-direction: column;
    width: 100%;
    height: 100vh;
    padding: 6px 10px 4px 10px;
    gap: 6px;
}

.sr-only {
    position: absolute;
    width: 1px;
    height: 1px;
    overflow: hidden;
    clip: rect(0 0 0 0);
}

/* ===========================================
   TITLE (Top Center)
   =========================================== */
.title-bar {
    text-align: center;
    flex: 0 0 auto;
}

.title {
    font-size: 20px;
    font-weight: bold;
}

.subtitle {
    font-size: 16px;
    color: #333;
    font-style: italic;
    margin-top: 2px;
}

/* ===========================================
   TWO-COLUMN LAYOUT
   =========================================== */
.layout {
    flex: 1 1 auto;
    min-height: 0;
    display: flex;
    gap: 10px;
}

.left-col {
    flex: 1 1 auto;
    min-width: 0;
    display: flex;
    flex-direction: column;
    gap: 4px;
}

.graph-wrap {
    position: relative;
    flex: 1 1 auto;
    min-height: 200px;
    background-color: white;
    border: 1px solid #c9d6e3;
    border-radius: 8px;
    overflow: hidden;
}

#network {
    width: 100%;
    height: 100%;
}

.legend {
    flex: 0 0 auto;
    font-size: 14px;
    line-height: 1.3;
    color: #333;
    display: flex;
    flex-wrap: wrap;
    column-gap: 8px;
}

.legend [hidden] { display: none; }

.lg-crit {
    font-weight: bold;
    color: #8a3c00;
    border: 2px solid #d55e00;
    border-radius: 4px;
    padding: 0 3px;
    background: #fdebd3;
}

/* ===========================================
   RIGHT PANEL (Questions)
   =========================================== */
.right-panel {
    flex: 0 0 360px;
    display: flex;
    flex-direction: column;
    gap: 7px;
    background-color: rgba(255, 255, 255, 0.95);
    border-radius: 8px;
    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
    padding: 8px 10px;
    min-height: 0;
    overflow-y: auto;   /* fallback only; content is sized to fit at >= 720px */
}

.q-step {
    font-size: 16px;
    font-weight: bold;
    color: #003f73;
}

.question {
    font-size: 17px;
    line-height: 1.35;
    font-weight: bold;
}

.answer-row {
    display: flex;
    align-items: center;
    gap: 8px;
}

.answer-row[hidden], .task-picks[hidden], .t3-row[hidden], .btn[hidden] { display: none; }

#answer-input {
    width: 90px;
    font-size: 17px;
    padding: 5px 8px;
    border: 2px solid #0072b2;
    border-radius: 6px;
}

#answer-input:disabled {
    background: #eef2f5;
    border-color: #9cb3c6;
    color: #333;
}

.unit { font-size: 16px; }

.task-picks {
    display: flex;
    flex-wrap: wrap;
    gap: 5px;
}

.pick-btn {
    font-size: 15px;
    font-weight: bold;
    min-width: 50px;
    padding: 5px 6px;
    border: 2px solid #0072b2;
    border-radius: 6px;
    background: #ffffff;
    color: #003f73;
    cursor: pointer;
}

.pick-btn[aria-pressed="true"] {
    background: #0072b2;
    color: #ffffff;
}

.pick-btn:disabled { cursor: default; }
.pick-btn:disabled[aria-pressed="false"] { border-color: #9cb3c6; color: #555; }

.t3-row {
    display: flex;
    align-items: center;
    gap: 10px;
    font-size: 16px;
    padding: 5px 8px;
    border: 2px solid #d55e00;
    border-radius: 6px;
    background: #fdf5ea;
}

.t3-row input { flex: 1 1 auto; min-width: 80px; }

.controls {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
    align-items: center;
}

.btn {
    padding: 7px 14px;
    font-size: 15px;
    font-weight: bold;
    border: none;
    border-radius: 6px;
    cursor: pointer;
}

.btn:focus-visible, .pick-btn:focus-visible, #answer-input:focus-visible,
#detail-select:focus-visible, #t3-slider:focus-visible {
    outline: 3px solid #56b4e9;
    outline-offset: 2px;
}

.btn-primary { background-color: #0072b2; color: white; }
.btn-primary:hover { background-color: #005a8c; }
.btn-primary:disabled { background-color: #9cc3dd; cursor: not-allowed; }

.btn-secondary { background-color: #616161; color: white; }
.btn-secondary:hover { background-color: #4a4a4a; }

.feedback {
    font-size: 15px;
    line-height: 1.38;
}

.feedback:empty { display: none; }

.fb {
    padding: 6px 9px;
    border-radius: 6px;
    border-left: 5px solid #0072b2;
    background: #eef6fc;
}

.fb.fb-wrong {
    border-left-color: #d55e00;
    border-left-style: dashed;
    background: #fdf0e1;
}

.fb.fb-note {
    border-left-color: #888;
    background: #f3f3f3;
}

.fb + .fb { margin-top: 5px; }

.fb-final { font-weight: bold; }

.score {
    font-size: 15px;
    font-weight: bold;
}

.explore {
    margin-top: auto;
    border-top: 1px solid #d5dee8;
    padding-top: 6px;
    font-size: 15px;
}

.explore-label { font-weight: bold; margin-right: 4px; }

#detail-select {
    font-size: 15px;
    padding: 2px 4px;
}

.detail {
    margin-top: 4px;
    line-height: 1.35;
    min-height: 2.7em;
}

.back-link {
    flex: 0 0 auto;
    font-size: 14px;
    color: #005a8c;
}

/* ===========================================
   RESPONSIVE: stack below 720px
   =========================================== */
@media (max-width: 719px) {
    .container { padding: 4px 6px 2px 6px; gap: 4px; }
    .title { font-size: 18px; }
    .subtitle { font-size: 15px; }
    /* The tall dependency graph cannot be read at phone width inside a fixed
       iframe height, so below 720px the graph keeps a readable height and the
       stacked graph + question panel scroll together inside the page. */
    .layout { flex-direction: column; gap: 4px; overflow-y: auto; }
    .left-col { flex: 0 0 auto; }
    .graph-wrap { flex: 0 0 auto; height: 540px; }
    .right-panel { flex: 0 0 auto; padding: 6px 8px; gap: 5px; }
    .question { font-size: 16px; }
    .feedback { font-size: 14px; }
    .btn { padding: 6px 11px; font-size: 14px; }
    .pick-btn { min-width: 42px; padding: 4px 4px; font-size: 14px; }
    .explore { font-size: 14px; }
    .detail { min-height: 0; }
}

/* xAPI teaching panel (?xapi=teaching): pin the layout to its production height and let the page scroll. */
html:has(.xapi-panel), body:has(.xapi-panel) { height: auto; overflow: auto; }
body:has(.xapi-panel) .container { height: 760px; }