/* =====================================================================
   Interactive 2D Beam Solver - stylesheet
   ===================================================================== */

:root {
  color-scheme: light;

  --surface-0:  #f4f4f1;      /* page */
  --surface-1:  #fcfcfb;      /* cards, canvas */
  --surface-2:  #eeeeea;      /* inset / inputs */
  --surface-3:  #e4e4df;      /* hover */
  --border:     #d8d8d2;
  --border-strong: #bfbfb7;

  --text-primary:   #17171a;
  --text-secondary: #52514e;
  --text-muted:     #83837c;

  --accent:      #2a78d6;
  --accent-ink:  #ffffff;
  --accent-soft: #e3eefb;

  --good:    #1f7a4d;
  --warn:    #a8630a;
  --bad:     #b3261e;
  --warn-bg: #fdf3e3;
  --bad-bg:  #fbeae8;
  --good-bg: #e7f4ec;

  /* diagram series - validated order (see README) */
  --c-axial: #008300;
  --c-shear: #2a78d6;
  --c-moment:#eb6834;
  --c-slope: #4a3aa7;
  --c-defl:  #1baf7a;
  --c-load:  #e34948;

  --beam-ink:    #2f2f33;
  --support-ink: #45454b;
  --grid:        #e6e6e1;
  --grid-strong: #cfcfc8;

  --radius: 10px;
  --radius-sm: 7px;
  --shadow: 0 1px 2px rgba(0,0,0,.05), 0 4px 14px rgba(0,0,0,.05);
  --mono: ui-monospace, "SF Mono", "Cascadia Mono", "JetBrains Mono", Menlo, Consolas, monospace;
  --sans: system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
}

@media (prefers-color-scheme: dark) {
  :root:where(:not([data-theme="light"])) {
    color-scheme: dark;
    --surface-0:  #121211;
    --surface-1:  #1a1a19;
    --surface-2:  #232322;
    --surface-3:  #2e2e2c;
    --border:     #343431;
    --border-strong: #4a4a46;

    --text-primary:   #f4f4f0;
    --text-secondary: #c3c2b7;
    --text-muted:     #8e8e85;

    --accent:      #3987e5;
    --accent-ink:  #0a0a0a;
    --accent-soft: #17293f;

    --good:    #4bbd85;
    --warn:    #e0a951;
    --bad:     #e66767;
    --warn-bg: #2c2313;
    --bad-bg:  #2e1917;
    --good-bg: #12281d;

    --c-axial: #008300;
    --c-shear: #3987e5;
    --c-moment:#d95926;
    --c-slope: #9085e9;
    --c-defl:  #199e70;
    --c-load:  #e66767;

    --beam-ink:    #d9d9d3;
    --support-ink: #b9b9b2;
    --grid:        #262624;
    --grid-strong: #3a3a37;
    --shadow: 0 1px 2px rgba(0,0,0,.4), 0 4px 16px rgba(0,0,0,.35);
  }
}

:root[data-theme="dark"] {
  color-scheme: dark;
  --surface-0:  #121211;
  --surface-1:  #1a1a19;
  --surface-2:  #232322;
  --surface-3:  #2e2e2c;
  --border:     #343431;
  --border-strong: #4a4a46;

  --text-primary:   #f4f4f0;
  --text-secondary: #c3c2b7;
  --text-muted:     #8e8e85;

  --accent:      #3987e5;
  --accent-ink:  #0a0a0a;
  --accent-soft: #17293f;

  --good:    #4bbd85;
  --warn:    #e0a951;
  --bad:     #e66767;
  --warn-bg: #2c2313;
  --bad-bg:  #2e1917;
  --good-bg: #12281d;

  --c-axial: #008300;
  --c-shear: #3987e5;
  --c-moment:#d95926;
  --c-slope: #9085e9;
  --c-defl:  #199e70;
  --c-load:  #e66767;

  --beam-ink:    #d9d9d3;
  --support-ink: #b9b9b2;
  --grid:        #262624;
  --grid-strong: #3a3a37;
  --shadow: 0 1px 2px rgba(0,0,0,.4), 0 4px 16px rgba(0,0,0,.35);
}

* { box-sizing: border-box; }

html, body { height: 100%; }

body {
  margin: 0;
  background: var(--surface-0);
  color: var(--text-primary);
  font: 14.5px/1.5 var(--sans);
  -webkit-font-smoothing: antialiased;
  overflow: hidden;
}

/* ---------------------------------------------------------------- app */
.app {
  display: grid;
  grid-template-rows: auto 1fr;
  height: 100vh;
}

/* ------------------------------------------------------------- header */
.topbar {
  display: flex;
  align-items: center;
  gap: 7px;
  padding: 8px 12px;
  background: var(--surface-1);
  border-bottom: 1px solid var(--border);
  flex-wrap: wrap;
}
.brand { display: flex; align-items: baseline; gap: 9px; margin-right: 4px; }
.brand h1 { font-size: 17px; font-weight: 650; margin: 0; letter-spacing: -.01em; }
.brand .sub { font-size: 12.5px; color: var(--text-muted); }
.topbar .spacer { flex: 1 1 auto; }

.btn {
  appearance: none;
  border: 1px solid var(--border-strong);
  background: var(--surface-1);
  color: var(--text-primary);
  border-radius: var(--radius-sm);
  padding: 5px 9px;
  font: inherit;
  font-size: 13px;
  cursor: pointer;
  white-space: nowrap;
  display: inline-flex;
  align-items: center;
  gap: 6px;
  transition: background .12s, border-color .12s;
}
.btn:hover { background: var(--surface-3); }
.btn:active { transform: translateY(.5px); }
.btn:focus-visible { outline: 2px solid var(--accent); outline-offset: 1px; }
.btn.primary { background: var(--accent); border-color: var(--accent); color: var(--accent-ink); }
.btn.primary:hover { filter: brightness(1.08); }
.btn.danger { color: var(--bad); border-color: color-mix(in srgb, var(--bad) 40%, var(--border)); }
.btn.small { padding: 3px 7px; font-size: 12.5px; }
.btn[disabled] { opacity: .45; cursor: not-allowed; }
.btn .kbd { font-size: 11.5px; color: var(--text-muted); }

.seg { display: inline-flex; border: 1px solid var(--border-strong); border-radius: var(--radius-sm); overflow: hidden; }
.seg button {
  appearance: none; border: 0; background: var(--surface-1); color: var(--text-secondary);
  font: inherit; font-size: 13.5px; padding: 5px 11px; cursor: pointer;
}
.seg button + button { border-left: 1px solid var(--border); }
.seg button[aria-pressed="true"] { background: var(--accent); color: var(--accent-ink); font-weight: 600; }

/* -------------------------------------------------------------- body */
.main {
  display: grid;
  grid-template-columns: 336px 1fr;
  min-height: 0;
}
.sidebar {
  border-right: 1px solid var(--border);
  background: var(--surface-1);
  overflow-y: auto;
  overscroll-behavior: contain;
  padding-bottom: 40px;
}
.workspace { overflow-y: auto; overscroll-behavior: contain; padding: 14px 16px 60px; }

/* ---------------------------------------------------------- sidebar */
.panel { border-bottom: 1px solid var(--border); }
.panel > summary {
  list-style: none;
  cursor: pointer;
  padding: 9px 12px;
  font-weight: 600;
  font-size: 13.5px;
  letter-spacing: .02em;
  text-transform: uppercase;
  color: var(--text-secondary);
  display: flex;
  align-items: center;
  gap: 7px;
  user-select: none;
}
.panel > summary::-webkit-details-marker { display: none; }
.panel > summary::before {
  content: "";
  width: 0; height: 0;
  border-left: 4.5px solid currentColor;
  border-top: 3.5px solid transparent;
  border-bottom: 3.5px solid transparent;
  transition: transform .15s;
  opacity: .6;
}
.panel[open] > summary::before { transform: rotate(90deg); }
.panel > summary:hover { background: var(--surface-2); }
.panel .body { padding: 2px 12px 13px; }

.field { display: grid; grid-template-columns: 1fr auto; gap: 6px; align-items: center; margin-bottom: 7px; }
.field label { font-size: 13.5px; color: var(--text-secondary); }
.field .unit { font-size: 12.5px; color: var(--text-muted); min-width: 38px; }
.field .unit:empty { min-width: 0; }   /* the Material row has no unit - give the select the space */
.field input[type="number"], .field input[type="text"], .field select { width: 100%; }
.field.wide { grid-template-columns: 96px 1fr auto; }

input[type="number"], input[type="text"], select {
  width: 100%;
  background: var(--surface-2);
  border: 1px solid var(--border);
  color: var(--text-primary);
  border-radius: 6px;
  padding: 4px 7px;
  font: inherit;
  font-size: 13.5px;
  font-variant-numeric: tabular-nums;
}
input[type="number"]:focus, input[type="text"]:focus, select:focus {
  outline: none; border-color: var(--accent); background: var(--surface-1);
  box-shadow: 0 0 0 2px var(--accent-soft);
}
input[type="range"] { width: 100%; accent-color: var(--accent); }
input[type="checkbox"] { accent-color: var(--accent); }

.row2 { display: grid; grid-template-columns: 1fr 1fr; gap: 6px; }
.row3 { display: grid; grid-template-columns: 1fr 1fr 1fr; gap: 6px; }
.hint { font-size: 12.5px; color: var(--text-muted); margin: 4px 0 8px; line-height: 1.45; }
.addbar { display: flex; flex-wrap: wrap; gap: 5px; margin-bottom: 9px; }

/* object lists */
.olist { display: flex; flex-direction: column; gap: 3px; }
.oitem {
  display: grid;
  grid-template-columns: 20px 1fr auto;
  align-items: center;
  gap: 7px;
  padding: 5px 7px;
  border: 1px solid transparent;
  border-radius: 6px;
  cursor: pointer;
  background: var(--surface-2);
}
.oitem:hover { background: var(--surface-3); }
.oitem.sel { border-color: var(--accent); background: var(--accent-soft); }
.oitem .glyph { display: grid; place-items: center; color: var(--text-secondary); }
.oitem .txt { font-size: 13.5px; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.oitem .txt b { font-weight: 600; }
.oitem .txt .dim { color: var(--text-muted); font-variant-numeric: tabular-nums; }
.oitem .x { opacity: 0; border: 0; background: none; color: var(--text-muted); cursor: pointer; font-size: 15.5px; line-height: 1; padding: 2px 4px; border-radius: 4px; }
.oitem:hover .x, .oitem.sel .x { opacity: 1; }
.oitem .x:hover { color: var(--bad); background: var(--surface-1); }
.empty { font-size: 13.5px; color: var(--text-muted); font-style: italic; padding: 3px 0 6px; }

/* --------------------------------------------------------- workspace */
.card {
  background: var(--surface-1);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  margin-bottom: 14px;
}
.card > header {
  display: flex; align-items: center; gap: 10px;
  padding: 8px 13px;
  border-bottom: 1px solid var(--border);
  flex-wrap: wrap;
}
.card > header h2 { font-size: 14px; font-weight: 650; margin: 0; letter-spacing: .01em; }
.card > header .spacer { flex: 1 1 auto; }
.card .pad { padding: 12px 13px; }

#stage { display: block; width: 100%; height: auto; touch-action: none; }
.stagewrap { position: relative; padding: 4px 2px 2px; }

.tip {
  position: absolute;
  pointer-events: none;
  background: var(--surface-1);
  border: 1px solid var(--border-strong);
  border-radius: 7px;
  box-shadow: var(--shadow);
  padding: 7px 9px;
  font-size: 13px;
  min-width: 148px;
  z-index: 20;
  opacity: 0;
  transition: opacity .1s;
}
.tip.on { opacity: 1; }
.tip .th { font-weight: 650; margin-bottom: 4px; font-variant-numeric: tabular-nums; }
.tip table { border-collapse: collapse; width: 100%; }
.tip td { padding: 1px 0; font-variant-numeric: tabular-nums; }
.tip td:first-child { color: var(--text-secondary); padding-right: 10px; }
.tip td:last-child { text-align: right; font-weight: 600; }
.tip .sw { display: inline-block; width: 7px; height: 7px; border-radius: 2px; margin-right: 5px; vertical-align: middle; }

/* results */
.grid-cards { display: grid; grid-template-columns: repeat(auto-fit, minmax(280px, 1fr)); gap: 14px; align-items: start; }

table.data { width: 100%; border-collapse: collapse; font-size: 13.5px; }
table.data th, table.data td { padding: 5px 8px; text-align: right; border-bottom: 1px solid var(--border); font-variant-numeric: tabular-nums; }
table.data th { color: var(--text-secondary); font-weight: 600; font-size: 12.5px; text-transform: uppercase; letter-spacing: .03em; white-space: nowrap; }
table.data th:first-child, table.data td:first-child { text-align: left; }
table.data tbody tr:last-child td { border-bottom: 0; }
table.data tbody tr:hover { background: var(--surface-2); }
table.data td.num { font-family: var(--mono); font-size: 13px; }

.kv { display: grid; grid-template-columns: auto 1fr; gap: 4px 12px; font-size: 13.5px; }
.kv dt { color: var(--text-secondary); }
.kv dd { margin: 0; text-align: right; font-weight: 600; font-variant-numeric: tabular-nums; }

.badge {
  display: inline-flex; align-items: center; gap: 5px;
  font-size: 12.5px; font-weight: 600;
  padding: 2px 7px; border-radius: 20px;
  border: 1px solid transparent;
}
.badge.good { background: var(--good-bg); color: var(--good); border-color: color-mix(in srgb, var(--good) 25%, transparent); }
.badge.warn { background: var(--warn-bg); color: var(--warn); border-color: color-mix(in srgb, var(--warn) 25%, transparent); }
.badge.bad  { background: var(--bad-bg);  color: var(--bad);  border-color: color-mix(in srgb, var(--bad) 25%, transparent); }
.badge.neutral { background: var(--surface-2); color: var(--text-secondary); border-color: var(--border); }

.note {
  border-left: 3px solid var(--warn);
  background: var(--warn-bg);
  color: var(--text-primary);
  padding: 7px 10px;
  border-radius: 0 6px 6px 0;
  font-size: 13.5px;
  margin-bottom: 10px;
}
.note.err { border-color: var(--bad); background: var(--bad-bg); }

.chips { display: flex; flex-wrap: wrap; gap: 5px; }
.chip {
  font-size: 13px; padding: 3px 9px; border-radius: 20px;
  border: 1px solid var(--border-strong); background: var(--surface-1);
  cursor: pointer; color: var(--text-secondary);
}
.chip:hover { background: var(--surface-3); color: var(--text-primary); }

.togs { display: flex; flex-wrap: wrap; gap: 4px 14px; }
.tog { display: inline-flex; align-items: center; gap: 5px; font-size: 13.5px; cursor: pointer; user-select: none; color: var(--text-secondary); }
.tog input { margin: 0; }
.tog .sw { width: 9px; height: 9px; border-radius: 2px; }

/* svg helpers */
.hit { cursor: ew-resize; }
.grabbable { cursor: grab; }
text { user-select: none; }

/* modal */
.modal-back {
  position: fixed; inset: 0; background: rgba(0,0,0,.45);
  display: grid; place-items: center; z-index: 100; padding: 20px;
}
.modal {
  background: var(--surface-1); border: 1px solid var(--border-strong);
  border-radius: 12px; box-shadow: 0 20px 60px rgba(0,0,0,.35);
  max-width: 760px; width: 100%; max-height: 84vh; overflow: auto;
}
.modal header { padding: 12px 16px; border-bottom: 1px solid var(--border); display: flex; align-items: center; }
.modal header h2 { margin: 0; font-size: 15.5px; }
.modal .pad { padding: 14px 16px; }
.modal h3 { font-size: 14px; margin: 16px 0 6px; }
.modal h3:first-child { margin-top: 0; }
.modal p, .modal li { font-size: 14px; color: var(--text-secondary); line-height: 1.6; }
.modal code { font-family: var(--mono); font-size: 13px; background: var(--surface-2); padding: 1px 4px; border-radius: 4px; color: var(--text-primary); }
.modal textarea {
  width: 100%; min-height: 220px; font-family: var(--mono); font-size: 13px;
  background: var(--surface-2); color: var(--text-primary);
  border: 1px solid var(--border); border-radius: 6px; padding: 8px;
}

.toast {
  position: fixed; left: 50%; bottom: 22px; transform: translateX(-50%) translateY(8px);
  background: var(--text-primary); color: var(--surface-1);
  padding: 8px 14px; border-radius: 20px; font-size: 13.5px; font-weight: 500;
  opacity: 0; pointer-events: none; transition: opacity .18s, transform .18s; z-index: 200;
}
.toast.on { opacity: 1; transform: translateX(-50%) translateY(0); }

/* --------------------------------------------------------- responsive */
@media (max-width: 900px) {
  body { overflow: auto; }
  .app { height: auto; }
  .main { grid-template-columns: 1fr; }
  .sidebar { border-right: 0; border-bottom: 1px solid var(--border); max-height: none; overflow: visible; }
  .workspace { overflow: visible; padding: 12px; }
}

/* ------------------------------------------------------------- print */
@media print {
  body { overflow: visible; background: #fff; }
  .app { height: auto; display: block; }
  .topbar, .sidebar, .no-print { display: none !important; }
  .main { display: block; }
  .workspace { overflow: visible; padding: 0; }
  .card { break-inside: avoid; box-shadow: none; border-color: #ccc; margin-bottom: 10px; }
  .grid-cards { grid-template-columns: 1fr 1fr; }
}