/* Strings — string tension calculator */

* { box-sizing: border-box; }

:root {
  --bg: #070a12;
  --bg2: #0c1120;
  --panel: #0e1424;
  --line: #1c2438;
  --line2: #151c2e;
  --ink: #e8e4d8;
  --dim: #8b90a0;
  --gold: #f4c15d;
  --red: #b0483c;
  --teal: #5da8a0;
  --bronze: #c87f4a;
  color-scheme: dark;
}

html, body {
  margin: 0; padding: 0;
  background: var(--bg);
  color: var(--ink);
  font-family: "IBM Plex Mono", ui-monospace, monospace;
  font-size: 13px;
}

/* ---------- header ---------- */

.top {
  display: flex; align-items: center; gap: 14px;
  padding: 10px 16px;
  border-bottom: 1px solid var(--line);
  position: sticky; top: 0; z-index: 5;
  background: color-mix(in srgb, var(--bg) 88%, transparent);
  backdrop-filter: blur(6px);
}
.top__home { color: var(--dim); text-decoration: none; font-size: 12px; white-space: nowrap; }
.top__home:hover { color: var(--gold); }
.top__brand {
  font-family: "Marcellus", serif;
  font-size: 21px; font-weight: 400; margin: 0; letter-spacing: 0.06em;
  color: var(--gold);
}
.top__sub { color: var(--dim); font-size: 11px; margin-right: auto; }
.top__actions { display: flex; gap: 8px; margin-left: auto; align-items: center; }

button {
  font: inherit; cursor: pointer;
  background: none; color: var(--ink);
  border: 1px solid var(--line); border-radius: 7px;
  padding: 6px 12px;
  transition: border-color .15s, color .15s, background .15s;
}
button:hover { border-color: var(--gold); color: var(--gold); }
button:focus-visible, input:focus-visible, select:focus-visible { outline: 1px solid var(--gold); outline-offset: 2px; }

.seg { display: inline-flex; border: 1px solid var(--line); border-radius: 7px; overflow: hidden; }
.seg button { border: 0; border-radius: 0; padding: 5px 12px; font-size: 11px; color: var(--dim); }
.seg .seg--on, .seg button.seg--on:hover { background: var(--gold); color: #201607; }

/* ---------- page column ---------- */

.wrap { max-width: 820px; margin: 0 auto; padding: 22px 18px 70px; }

/* instrument head: the name itself is the picker */
.head {
  display: flex; align-items: baseline; gap: 14px; flex-wrap: wrap;
  margin: 26px 0 4px;
}
.pick { position: relative; }
.pick__btn {
  font-family: "Marcellus", serif; font-weight: 400;
  font-size: 28px; letter-spacing: .03em; color: var(--ink);
  border: 0; border-bottom: 1px solid transparent; border-radius: 0;
  padding: 0 0 2px; display: inline-flex; align-items: baseline; gap: 10px;
  text-align: left;
}
.pick__btn:hover { color: var(--ink); border-bottom-color: var(--line); }
.pick__btn:hover .pick__caret, .pick--open .pick__caret { color: var(--gold); }
.pick--open .pick__btn { border-bottom-color: var(--gold); }
.pick__caret { color: var(--dim); font-size: 13px; transition: transform .18s, color .15s; }
.pick--open .pick__caret { transform: rotate(180deg); }

/* the instrument list is a collapsible drawer that pushes the page down */
.drawer {
  display: grid; grid-template-rows: 0fr;
  transition: grid-template-rows .26s cubic-bezier(.4, 0, .2, 1);
}
.drawer--open { grid-template-rows: 1fr; }
.drawer__in { overflow: hidden; min-height: 0; visibility: hidden; transition: visibility 0s .26s; }
.drawer--open .drawer__in { visibility: visible; transition: none; }

.pick__menu {
  display: grid; grid-template-columns: repeat(3, 1fr); gap: 2px;
  margin: 12px 0 6px; padding: 6px;
  background: var(--panel); border: 1px solid var(--line); border-radius: 10px;
}
.pick__opt {
  border: 0; border-radius: 7px; padding: 7px 11px;
  display: flex; flex-direction: column; align-items: flex-start; gap: 1px;
  color: var(--ink); text-align: left; font-size: 12.5px; line-height: 1.3;
}
.pick__opt small { color: var(--dim); font-size: 10.5px; }
.pick__opt:hover, .pick__opt:focus-visible { background: var(--bg2); color: var(--gold); outline: none; }
.pick__opt--on { color: var(--gold); }
@media (max-width: 720px) { .pick__menu { grid-template-columns: 1fr 1fr; } }
@media (max-width: 460px) { .pick__menu { grid-template-columns: 1fr; } }
.head__sub { color: var(--dim); font-size: 11.5px; }
.scale { margin-left: auto; display: flex; align-items: baseline; gap: 8px; color: var(--dim); font-size: 11.5px; }
.scale input { width: 72px; text-align: right; font-size: 14px; color: var(--gold); }
.unit { color: var(--dim); font-size: 11px; }
.reset { font-size: 11px; padding: 4px 10px; color: var(--dim); }
.note { color: var(--dim); font-size: 11px; font-style: italic; margin: 6px 0 0; }

/* quiet inline fields: underline only */
input[type="number"], select {
  font: inherit; font-size: 12.5px;
  background: transparent; color: var(--ink);
  border: 0; border-bottom: 1px solid var(--line);
  border-radius: 0; padding: 4px 2px;
  min-width: 0;
  transition: border-color .15s;
}
input[type="number"]:hover, select:hover { border-bottom-color: var(--dim); }
input[type="number"]:focus, select:focus { outline: none; border-bottom-color: var(--gold); }
input[type="number"] { -moz-appearance: textfield; appearance: textfield; }
input[type="number"]::-webkit-inner-spin-button { opacity: 0; }
input[type="number"]:hover::-webkit-inner-spin-button,
input[type="number"]:focus::-webkit-inner-spin-button { opacity: 1; }
select { cursor: pointer; color-scheme: dark; }
select option { background: var(--panel); color: var(--ink); }

/* ---------- string editor ---------- */

.editor { margin-top: 22px; border-top: 1px solid var(--line); }

.cols, .srow {
  display: grid;
  grid-template-columns: 30px 48px 104px 160px 84px 1fr 22px;
  gap: 14px; align-items: center;
}
.cols { color: var(--dim); font-size: 10.5px; padding: 8px 0 2px; }
.cols span:nth-child(5), .cols span:nth-child(6) { text-align: right; }

.srow { padding: 3px 0; }
.srow--first { border-top: 1px solid var(--line2); padding-top: 9px; }
.srow--last { padding-bottom: 9px; }
.srow:first-child.srow--first { border-top: 0; }

.srow__c { color: var(--dim); font-size: 11px; }
.sline { width: 48px; height: 12px; }
.sline svg { display: block; width: 48px; height: 12px; overflow: visible; }
.srow select, .srow input { width: 100%; }
.srow input { text-align: right; }
.srow__t { text-align: right; color: var(--gold); font-size: 13px; white-space: nowrap; }
.srow__t small { color: var(--dim); font-size: 10.5px; margin-left: 7px; }
.srow__del {
  border: 0; padding: 0; width: 22px; height: 22px; border-radius: 5px;
  color: var(--line); font-size: 15px; line-height: 1;
}
.srow:hover .srow__del { color: var(--dim); }
.srow__del:hover { color: var(--red) !important; }

.editor__foot {
  display: flex; align-items: baseline; gap: 14px; flex-wrap: wrap;
  padding: 14px 0 0; border-top: 1px solid var(--line);
}
.add { font-size: 11.5px; padding: 5px 11px; color: var(--dim); }
.total { margin-left: auto; color: var(--dim); font-size: 12px; }
.total b { color: var(--ink); font-weight: 500; font-size: 14px; margin: 0 6px; }

/* ---------- secondary results ---------- */

.results {
  display: grid; grid-template-columns: minmax(280px, 5fr) minmax(240px, 4fr); gap: 14px;
  margin-top: 34px;
}
.card {
  border: 1px solid var(--line); border-radius: 10px;
  padding: 12px 14px; overflow-x: auto;
}
.card h3 {
  font-family: "Marcellus", serif; font-weight: 400; font-size: 13px;
  letter-spacing: .05em; color: var(--dim); margin: 0 0 8px;
}

table.tens { width: 100%; border-collapse: collapse; font-size: 11.5px; color: var(--dim); }
table.tens th, table.tens td { white-space: nowrap; text-align: right; padding: 3px 6px; }
table.tens th { font-weight: 400; font-size: 10px; border-bottom: 1px solid var(--line); }
table.tens th:first-child, table.tens td:first-child,
table.tens th:nth-child(2), table.tens td:nth-child(2) { text-align: left; }
table.tens td.t-note { color: var(--ink); }
table.tens td.t-val { color: var(--ink); }
table.tens td .sub { color: var(--dim); }
table.tens tr.t-total td { border-top: 1px solid var(--line); color: var(--ink); padding-top: 6px; }

.chartwrap svg { width: 100%; height: auto; display: block; }
.legend { display: flex; flex-wrap: wrap; gap: 4px 12px; margin-top: 8px; }
.legend span { display: inline-flex; align-items: center; gap: 6px; color: var(--dim); font-size: 10.5px; }
.legend i { width: 9px; height: 9px; border-radius: 3px; display: inline-block; }

/* ---------- how it works ---------- */

details.how { margin-top: 18px; border-top: 1px solid var(--line); padding: 14px 0 0; }
details.how > summary {
  cursor: pointer; list-style: none;
  font-family: "Marcellus", serif; font-size: 14px; letter-spacing: .05em; color: var(--dim);
  display: flex; align-items: center; gap: 8px;
}
details.how > summary:hover { color: var(--gold); }
details.how > summary::-webkit-details-marker { display: none; }
details.how > summary::after { content: "▾"; margin-left: auto; font-size: 11px; transition: transform .15s; }
details.how:not([open]) > summary::after { transform: rotate(-90deg); }
.how__body { margin-top: 12px; color: var(--dim); font-size: 12px; line-height: 1.7; max-width: 72ch; }
.how__body p { margin: 0 0 10px; }
.how__body b, .how__body var { color: var(--ink); font-style: normal; }
.how__body .formula {
  display: block; text-align: center; color: var(--ink);
  font-size: 14px; margin: 12px 0; letter-spacing: .04em;
}
.how__body .formula var { color: var(--gold); }

.source { color: var(--dim); font-size: 10.5px; margin: 22px 0 0; }
.source a { color: var(--dim); text-decoration: underline dotted; }
.source a:hover { color: var(--gold); }

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after { transition: none !important; animation: none !important; }
}

/* ---------- narrow screens ---------- */

@media (max-width: 900px) { .results { grid-template-columns: 1fr; } }

@media (max-width: 680px) {
  .top__sub { display: none; }
  .head__name { font-size: 24px; }
  .scale { margin-left: 0; width: 100%; }
  .cols { display: none; }
  .srow {
    grid-template-columns: 30px 48px 1fr 22px;
    grid-template-areas:
      "c line . del"
      ". fields fields fields";
    gap: 6px 10px;
  }
  .srow__c { grid-area: c; }
  .sline { grid-area: line; }
  .srow__del { grid-area: del; color: var(--dim); }
  .srow__f {
    grid-area: fields;
    display: grid; grid-template-columns: 1fr 1.4fr 0.8fr 0.9fr; gap: 10px; align-items: center;
  }
  .srow__t small { display: none; }
}
@media (min-width: 681px) { .srow__f { display: contents; } }