/* HangSpine content pages (tools / scoliosis / blog / about)
   Design tokens mirror en/index.html so the whole site feels like one product. */

:root {
  --ink: #f5f5f7; --ink2: #a1a1a6; --bg: #0a0a0a; --bg2: #111113;
  --accent: #00ccff; --accent2: #64d2ff;
  --grad: linear-gradient(135deg, #64d2ff 0%, #5e5ce6 55%, #bf5af2 100%);
  --nav-bg: rgba(10,10,10,.82); --nav-border: rgba(255,255,255,.08);
  --card: #1c1c1e; --card-border: rgba(255,255,255,.05); --move: #161618;
  --icon-glow: rgba(94,92,230,.35); --cta-glow: rgba(94,92,230,.4);
  --footer-bg: #000; --theme-btn-color: #d2d2d7;
  --input-bg: #161618; --input-border: rgba(255,255,255,.14);
  --table-line: rgba(255,255,255,.08);
}
:root[data-theme="light"] {
  --ink: #1d1d1f; --ink2: #55555c; --bg: #ffffff; --bg2: #f5f5f7;
  --nav-bg: rgba(255,255,255,.85); --nav-border: rgba(0,0,0,.06);
  --card: #ffffff; --card-border: rgba(0,0,0,.06); --move: #f0f0f2;
  --icon-glow: rgba(94,92,230,.28); --cta-glow: rgba(94,92,230,.3);
  --footer-bg: #111; --theme-btn-color: #55555c;
  --input-bg: #fff; --input-border: rgba(0,0,0,.16);
  --table-line: rgba(0,0,0,.08);
}
* { box-sizing: border-box; }
html { background: var(--bg); }
body { margin: 0; font-family: -apple-system, "PingFang SC", "Helvetica Neue", sans-serif;
       color: var(--ink); background: var(--bg); line-height: 1.75;
       transition: background .25s ease, color .25s ease; }
a { color: var(--accent2); text-decoration: none; }
a:hover { text-decoration: underline; }
.wrap { max-width: 1020px; margin: 0 auto; padding: 0 22px; }

/* ---- nav (same as home) ---- */
nav { position: sticky; top: 0; z-index: 9; backdrop-filter: blur(14px);
      background: var(--nav-bg); border-bottom: 1px solid var(--nav-border); }
nav .wrap { display: flex; align-items: center; justify-content: space-between; height: 52px; }
.brand { font-weight: 700; font-size: 1.05rem; color: var(--ink); display: flex; align-items: center; gap: 9px; }
.brand:hover { text-decoration: none; }
.brand-icon { width: 26px; height: 26px; border-radius: 22%; }
.navlinks { display: flex; gap: 16px; font-size: .88rem; align-items: center; }
.navlinks a { color: var(--ink2); }
.navlinks a:hover { color: var(--ink); text-decoration: none; }
.navlinks a[aria-current="page"] { color: var(--accent2); }
.theme-toggle { background: none; border: 1px solid var(--nav-border); color: var(--theme-btn-color);
                border-radius: 999px; width: 30px; height: 30px; cursor: pointer; font-size: .9rem;
                display: inline-flex; align-items: center; justify-content: center; padding: 0; }
.theme-toggle:hover { border-color: var(--ink2); }
@media (max-width: 700px) { .navlinks a:not(.keep) { display: none; } }

/* ---- page head (compact hero for content pages) ---- */
.page-head { padding: 64px 0 30px; }
.kicker { font-weight: 600; letter-spacing: .18em; font-size: .78rem; color: var(--accent); }
.page-head h1 { font-size: clamp(1.7rem, 4.6vw, 2.6rem); line-height: 1.25; margin: 10px 0 12px;
                font-weight: 800; background: var(--grad);
                -webkit-background-clip: text; background-clip: text; color: transparent; }
.page-head .sub { color: var(--ink2); font-size: 1.05rem; max-width: 720px; margin: 0; }
.breadcrumb { font-size: .8rem; color: var(--ink2); margin: 0 0 8px; }
.breadcrumb a { color: var(--ink2); }

main { padding-bottom: 64px; }
h2 { font-size: clamp(1.3rem, 3.4vw, 1.8rem); margin: 44px 0 10px; font-weight: 800; }
h3 { font-size: 1.12rem; margin: 30px 0 6px; }

/* ---- article prose ---- */
.prose { max-width: 740px; }
.prose p { margin: 14px 0; color: var(--ink); }
.prose p, .prose li { font-size: 1.01rem; }
.prose ul, .prose ol { padding-left: 22px; margin: 12px 0; }
.prose li { margin: 6px 0; }
.prose strong { color: var(--ink); }
.tldr { background: var(--card); border: 1px solid var(--card-border); border-radius: 16px;
        padding: 18px 22px; margin: 20px 0; }
.tldr .t { font-weight: 700; color: var(--accent); font-size: .8rem; letter-spacing: .12em; }
.note { border-left: 3px solid var(--accent); background: var(--bg2); border-radius: 0 12px 12px 0;
        padding: 12px 18px; margin: 18px 0; font-size: .92rem; color: var(--ink2); }
.note strong { color: var(--ink); }
.refs { padding-left: 22px; font-size: .88rem; color: var(--ink2); }
.refs li { margin: 8px 0; }
.byline { display: flex; align-items: center; gap: 12px; margin: 18px 0; font-size: .88rem; color: var(--ink2); }
.byline img { width: 40px; height: 40px; border-radius: 22%; }

/* ---- cards & grids ---- */
.grid3 { display: grid; grid-template-columns: repeat(3, 1fr); gap: 22px; margin-top: 28px; }
.grid2 { display: grid; grid-template-columns: 1fr 1fr; gap: 22px; margin-top: 28px; }
@media (max-width: 820px) { .grid3 { grid-template-columns: 1fr; } .grid2 { grid-template-columns: 1fr; } }
.card { background: var(--card); border: 1px solid var(--card-border); border-radius: 20px; padding: 26px 22px; }
.card h4 { margin: 0 0 6px; font-size: 1.02rem; }
.card p { margin: 0 0 10px; color: var(--ink2); font-size: .9rem; }
.card a.more { font-size: .88rem; font-weight: 600; }
.chip { display: inline-block; font-size: .72rem; font-weight: 700; border-radius: 999px;
        padding: 2px 10px; margin: 0 6px 8px 0; }
.chip.edu { color: #64d2ff; background: rgba(0,204,255,.1); border: 1px solid rgba(0,204,255,.35); }
.chip.ev  { color: #9Be4c0; background: rgba(52,199,89,.12); border: 1px solid rgba(52,199,89,.35); }
.chip.com { color: #ffd60a; background: rgba(255,214,10,.1); border: 1px solid rgba(255,214,10,.35); }

/* ---- exercise step list ---- */
.steps-list { counter-reset: s; margin: 10px 0; padding: 0; list-style: none; }
.steps-list li { counter-increment: s; position: relative; padding-left: 38px; margin: 8px 0; font-size: .95rem; }
.steps-list li::before { content: counter(s); position: absolute; left: 0; top: 2px;
       width: 26px; height: 26px; border-radius: 50%; background: var(--grad); color: #fff;
       font-weight: 700; font-size: .85rem; display: inline-flex; align-items: center; justify-content: center; }

/* ---- tables ---- */
table { width: 100%; border-collapse: collapse; margin: 18px 0; font-size: .92rem; }
th, td { padding: 9px 12px; text-align: left; border-bottom: 1px solid var(--table-line); }
th { color: var(--ink2); font-size: .8rem; text-transform: uppercase; letter-spacing: .06em; }
td strong { color: var(--accent2); }
caption { caption-side: bottom; text-align: left; font-size: .8rem; color: var(--ink2); padding-top: 8px; }

/* ---- tool form ---- */
.tool-box { background: var(--card); border: 1px solid var(--card-border); border-radius: 22px;
            padding: 30px 28px; margin: 26px 0; max-width: 740px; }
.frow { display: flex; gap: 18px; flex-wrap: wrap; margin: 14px 0; }
.frow label { flex: 1 1 150px; font-size: .85rem; color: var(--ink2); font-weight: 600; display: block; }
.frow input, .frow select { width: 100%; margin-top: 6px; background: var(--input-bg);
        border: 1px solid var(--input-border); color: var(--ink); border-radius: 12px;
        padding: 11px 14px; font-size: 1rem; font-family: inherit; }
.frow input:focus, .frow select:focus { outline: none; border-color: var(--accent); }
.btn { display: inline-flex; align-items: center; gap: 10px; margin-top: 10px; padding: 13px 30px;
       border-radius: 999px; background: var(--grad); color: #fff; font-weight: 700; font-size: 1rem;
       border: none; cursor: pointer; box-shadow: 0 12px 34px var(--cta-glow);
       transition: transform .15s ease, box-shadow .15s ease; }
.btn:hover { transform: translateY(-2px); color: #fff; box-shadow: 0 18px 44px var(--cta-glow); }
.result { margin-top: 22px; border-top: 1px solid var(--card-border); padding-top: 20px; }
.result .level { font-size: clamp(1.4rem, 4vw, 2rem); font-weight: 800;
                 background: var(--grad); -webkit-background-clip: text; background-clip: text; color: transparent; }
.result .meta { color: var(--ink2); font-size: .95rem; margin: 4px 0 14px; }
.kv { display: flex; gap: 14px; flex-wrap: wrap; }
.kv div { background: var(--move); border: 1px solid var(--card-border); border-radius: 14px;
          padding: 10px 16px; font-size: .9rem; }
.kv b { display: block; font-size: 1.05rem; }
.err { color: #ff6961; font-size: .88rem; margin-top: 8px; }

/* ---- FAQ ---- */
details { background: var(--card); border: 1px solid var(--card-border); border-radius: 14px;
          padding: 14px 20px; margin: 10px 0; }
details summary { cursor: pointer; font-weight: 600; }
details p { color: var(--ink2); font-size: .95rem; }

/* ---- footer (same as home) ---- */
footer { background: var(--footer-bg); color: #a1a1a6; padding: 44px 0 60px; font-size: .85rem; }
footer .wrap { display: flex; flex-wrap: wrap; gap: 24px; justify-content: space-between; }
footer a { color: #d2d2d7; }
.footer-icon { width: 26px; height: 26px; border-radius: 22%; vertical-align: -7px; margin-right: 8px; }
.disclaimer { border-top: 1px solid rgba(255,255,255,.12); margin-top: 26px; padding-top: 18px;
              font-size: .74rem; color: #86868b; max-width: 760px; }