/* Position Size Calculator — single stylesheet, no frameworks */

*, *::before, *::after { box-sizing: border-box; }

:root{
  --bg:#f6f7f9;
  --card:#ffffff;
  --ink:#111827;
  --ink-2:#4b5563;
  --ink-3:#6b7280;
  --line:#e5e7eb;
  --accent:#0f766e;
  --accent-soft:#ecfdf5;
  --warn:#92400e;
  --warn-bg:#fffbeb;
  --mono:ui-monospace,SFMono-Regular,Menlo,Consolas,monospace;
}

html,body{ margin:0; padding:0; }

body{
  background:var(--bg);
  color:var(--ink);
  font-family:-apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,Helvetica,Arial,sans-serif;
  font-size:16px;
  line-height:1.5;
  -webkit-text-size-adjust:100%;
}

.site{ padding:14px 18px 0; }
.brand{ font-weight:700; letter-spacing:-.01em; }
.tagline{ color:var(--ink-3); font-size:13px; }

main{ max-width:1080px; margin:0 auto; padding:18px; }

h1{
  font-size:26px;
  line-height:1.2;
  margin:10px 0 14px;
  letter-spacing:-.02em;
}

/* ---------- tool card ---------- */
.card{
  background:var(--card);
  border:1px solid var(--line);
  border-radius:14px;
  padding:16px;
  box-shadow:0 1px 2px rgba(16,24,40,.04);
}

.assetbar{ display:flex; gap:8px; margin-bottom:14px; flex-wrap:wrap; }
.assetbtn{
  font:inherit; font-size:14px; font-weight:600;
  padding:8px 14px; border-radius:999px;
  border:1px solid var(--line); background:#fff; color:var(--ink-2);
  cursor:pointer;
}
.assetbtn.is-on{ background:var(--accent); border-color:var(--accent); color:#fff; }

.grid{ display:grid; grid-template-columns:repeat(3,1fr); gap:12px; }

.pane{
  border:1px solid var(--line);
  border-radius:10px;
  padding:12px;
  background:#fcfcfd;
}
.pane-h{
  font-size:12px; font-weight:700; text-transform:uppercase;
  letter-spacing:.06em; color:var(--ink-3); margin-bottom:10px;
}

.f{ display:block; margin-bottom:10px; }
.f > span{
  display:block; font-size:12.5px; color:var(--ink-2); margin-bottom:4px; font-weight:600;
}
.f > span em{ font-style:normal; font-weight:400; color:var(--ink-3); }

input[type=number], select{
  width:100%; font:inherit; font-size:15px;
  padding:9px 10px;
  border:1px solid var(--line); border-radius:8px;
  background:#fff; color:var(--ink);
}
input[type=number]:focus, select:focus{ outline:2px solid var(--accent); outline-offset:0; border-color:var(--accent); }

.inline{ display:flex; gap:8px; }
.inline select{ flex:0 0 46%; }
.inline input{ flex:1 1 auto; min-width:0; }

.readonly{
  padding:9px 10px; border:1px dashed var(--line); border-radius:8px;
  background:#f9fafb; font-family:var(--mono); font-size:14px; color:var(--ink-2);
  min-height:38px;
}

/* ---------- results ---------- */
.results{ margin-top:16px; border-top:1px solid var(--line); padding-top:16px; }

.res-hero{ margin-bottom:14px; }
.res-label{ font-size:12.5px; font-weight:700; text-transform:uppercase; letter-spacing:.06em; color:var(--ink-3); }
.res-big{
  font-family:var(--mono); font-weight:700; color:var(--accent);
  font-size:34px; line-height:1.15; margin-top:2px; word-break:break-word;
}
.res-big small{ font-size:14px; font-family:inherit; font-weight:600; color:var(--ink-3); }
.res-lot{ font-family:var(--mono); font-size:15px; color:var(--ink-2); margin-top:2px; }
.res-lot small{ font-family:-apple-system,Segoe UI,Roboto,sans-serif; color:var(--ink-3); }

.res-grid{ display:grid; grid-template-columns:repeat(4,1fr); gap:10px; }
.r{
  border:1px solid var(--line); border-radius:10px; padding:9px 10px; background:#fcfcfd;
}
.r .k{ display:block; font-size:12px; color:var(--ink-3); font-weight:600; }
.r .v{ display:block; font-family:var(--mono); font-size:15px; margin-top:2px; word-break:break-word; }

.res-note:empty{ display:none; }
.res-note{
  margin-top:12px; padding:9px 11px; border-radius:8px;
  background:var(--warn-bg); border:1px solid #fde68a; color:var(--warn);
  font-size:13px;
}
.res-note p{ margin:0 0 4px; }
.res-note p:last-child{ margin-bottom:0; }

.res-actions{ margin-top:12px; display:flex; align-items:center; gap:10px; }
.copy{
  font:inherit; font-weight:600; font-size:14px; padding:9px 16px;
  border-radius:8px; border:1px solid var(--accent); background:var(--accent); color:#fff; cursor:pointer;
}
.copy:active{ transform:translateY(1px); }
.copied{ font-size:13px; color:var(--accent); font-weight:600; }

/* ---------- content below the fold ---------- */
.doc{
  margin-top:22px; background:var(--card); border:1px solid var(--line);
  border-radius:14px; padding:18px;
}
.doc h2{ font-size:19px; margin:0 0 10px; letter-spacing:-.01em; }
.doc p, .doc li{ color:var(--ink-2); font-size:15px; }
.doc ul, .doc ol{ padding-left:20px; }
.doc li{ margin-bottom:5px; }
.doc strong{ color:var(--ink); }
.doc em{ font-style:italic; }

details{ border-top:1px solid var(--line); padding:10px 0; }
details:first-of-type{ border-top:0; }
summary{ cursor:pointer; font-weight:600; font-size:15px; }
details p{ margin:8px 0 0; }

.site-foot{ max-width:1080px; margin:0 auto; padding:6px 18px 40px; color:var(--ink-3); font-size:13px; }
.foot-nav{ display:flex; flex-wrap:wrap; gap:16px; margin-bottom:10px; }
.foot-nav a{ color:var(--ink-2); font-size:14px; font-weight:600; text-decoration:none; border-bottom:1px solid var(--line); padding-bottom:2px; }
.foot-nav a:hover{ color:var(--ink); }

/* ---------- tablet ---------- */
@media (max-width:860px){
  .grid{ grid-template-columns:repeat(2,1fr); }
  .res-grid{ grid-template-columns:repeat(2,1fr); }
}

/* ---------- phone ---------- */
@media (max-width:560px){
  main{ padding:12px; }
  h1{ font-size:22px; }
  .card{ padding:12px; border-radius:12px; }
  .grid{ grid-template-columns:1fr; }
  .pane{ padding:11px; }
  .res-grid{ grid-template-columns:1fr; }
  .res-big{ font-size:28px; }
  input[type=number], select{ font-size:16px; }
  .inline{ flex-direction:column; }
  .inline select{ flex:none; width:100%; }
  .doc{ padding:14px; }
}