/* Axler Visual — shared styles
 * Loaded by every section page. Keep page-specific styles in page <style>. */

:root{
  --bg:#0b0d10; --panel:#14171c; --panel2:#1a1e24; --line:#262b34;
  --text:#e6e8eb; --dim:#8b929c;
  --accent:#f5b942;   /* amber: eigenvalues, main highlight */
  --cyan:#5cb3ff;     /* blue: normal vectors, type hints */
  --eig:#ffd166;      /* highlighted eigen-direction */
  --red:#ff6b6b;      /* complex / pathological */
  --teal:#4dd0e1;     /* trajectories */
  --violet:#c792ea;   /* orthonormal basis, secondary emphasis */
  --good:#66bb6a;     /* success state */
}
*{box-sizing:border-box}
html,body{
  margin:0;background:var(--bg);color:var(--text);
  font-family:-apple-system,"Segoe UI",Inter,system-ui,sans-serif;
  font-size:15px;line-height:1.58;
}
body{padding:40px 24px 160px;max-width:1280px;margin:0 auto}

/* Headings */
h1{font-size:28px;font-weight:600;margin:0 0 4px;letter-spacing:-0.01em}
h1 small{color:var(--dim);font-weight:400;font-size:16px;margin-left:8px}
h2{font-size:20px;font-weight:600;margin:48px 0 16px;color:var(--accent)}
h3{font-size:16px;margin:24px 0 10px}
h4{margin:14px 0 8px;font-size:15px;color:var(--cyan)}
p{margin:8px 0}
hr{border:0;border-top:1px solid var(--line);margin:32px 0}
.muted{color:var(--dim)}

/* Content blocks */
.card{background:var(--panel);border:1px solid var(--line);border-radius:10px;padding:20px;margin:20px 0}
.def{background:var(--panel);border-left:3px solid var(--accent);padding:14px 18px;border-radius:6px;margin:14px 0}
.thm{background:var(--panel);border-left:3px solid var(--cyan);padding:14px 18px;border-radius:6px;margin:14px 0}
.note{background:var(--panel2);padding:12px 16px;border-radius:6px;font-size:14px;color:var(--dim);margin:12px 0}
.formula{background:var(--panel2);padding:12px 16px;border-radius:6px;margin:10px 0;overflow-x:auto}

/* Layout */
.row{display:flex;gap:20px;align-items:flex-start;flex-wrap:wrap}
.col{flex:1 1 340px;min-width:0}

/* Canvas + controls */
canvas.plane{background:#070809;border-radius:6px;display:block;width:100%;height:auto;cursor:crosshair}
.ctl{display:flex;align-items:center;gap:10px;margin:6px 0}
.ctl label{min-width:24px;font-family:"JetBrains Mono",Consolas,monospace;color:var(--dim)}
.ctl input[type=range]{flex:1;accent-color:var(--accent)}
.ctl .val{min-width:48px;text-align:right;font-family:monospace;color:var(--accent)}
.matinput{display:grid;grid-template-columns:repeat(3,1fr);gap:6px;margin-top:10px;max-width:260px}
.matinput input{background:var(--panel2);border:1px solid var(--line);color:var(--text);padding:6px 8px;border-radius:4px;font-family:monospace;width:100%}
.readout{font-family:"JetBrains Mono",Consolas,monospace;font-size:13px;background:var(--panel2);padding:12px;border-radius:6px;white-space:pre-wrap;line-height:1.55}
.readout b{color:var(--eig)}
.readout .c{color:var(--red)}
.readout .ok{color:var(--good)}
.presets{display:flex;flex-wrap:wrap;gap:6px;margin:10px 0}
.presets button{background:var(--panel2);color:var(--text);border:1px solid var(--line);padding:5px 10px;border-radius:4px;cursor:pointer;font-size:12px;font-family:inherit}
.presets button:hover{border-color:var(--accent);color:var(--accent)}

/* Toggles (checkboxes + buttons below canvas) */
.toggles{display:flex;gap:14px;flex-wrap:wrap;padding:10px 2px;font-size:13px;color:var(--dim)}
.toggles label{display:inline-flex;align-items:center;gap:6px;cursor:pointer;user-select:none}
.toggles input[type=checkbox]{accent-color:var(--accent)}
.toggles button{background:var(--panel2);color:var(--text);border:1px solid var(--line);padding:3px 10px;border-radius:4px;cursor:pointer;font-size:12px}
.toggles button:hover{border-color:var(--accent);color:var(--accent)}

/* Legend under canvas */
.legend{display:flex;gap:16px;font-size:13px;color:var(--dim);margin-top:10px;flex-wrap:wrap}
.legend span::before{content:"";display:inline-block;width:10px;height:10px;border-radius:50%;margin-right:6px;vertical-align:middle}
.legend .n::before{background:var(--cyan)}
.legend .e::before{background:var(--eig)}
.legend .t::before{background:var(--teal)}
.legend .v::before{background:var(--violet)}
.legend .x::before{background:var(--red)}

/* 3D container */
.three-container{width:100%;height:520px;background:#050607;border-radius:6px;overflow:hidden}

/* Table of contents (fixed right) */
.toc{position:fixed;top:20px;right:20px;background:var(--panel);border:1px solid var(--line);border-radius:8px;padding:12px 16px;font-size:13px;max-width:220px;max-height:90vh;overflow-y:auto;z-index:10}
.toc .title{color:var(--accent);font-weight:600;margin-bottom:6px}
.toc a{color:var(--dim);text-decoration:none;display:block;padding:2px 0}
.toc a:hover{color:var(--accent)}
@media (max-width:920px){.toc{display:none}}

/* Glossary table */
table.glos{width:100%;border-collapse:collapse;font-size:14px}
table.glos th{text-align:left;padding:10px 12px;color:var(--accent);font-weight:600;border-bottom:2px solid var(--line);background:var(--panel2);font-size:13px;text-transform:uppercase;letter-spacing:0.03em}
table.glos td{padding:10px 12px;border-bottom:1px solid var(--line);vertical-align:top}
table.glos tr:last-child td{border-bottom:none}
table.glos tr:hover td{background:rgba(245,185,66,0.04)}
table.glos td.sym{white-space:nowrap;min-width:100px;color:var(--accent);font-weight:500}
table.glos td:nth-child(2){color:var(--dim);font-style:italic;min-width:120px;font-size:13px}
table.glos td:nth-child(4){color:var(--dim);font-size:13px;font-style:italic}

/* Q&A blocks */
.qa{margin:32px 0}
.q{font-size:19px;font-weight:600;color:var(--accent);margin:0 0 14px;padding-left:40px;position:relative;line-height:1.4;letter-spacing:-0.005em}
.q::before{content:"Q";position:absolute;left:0;top:-4px;background:var(--accent);color:#0b0d10;width:28px;height:28px;border-radius:50%;display:flex;align-items:center;justify-content:center;font-weight:700;font-size:15px;font-family:"JetBrains Mono",monospace}
.a{padding-left:40px;position:relative}
.a::before{content:"A";position:absolute;left:0;top:-2px;background:var(--panel2);color:var(--cyan);width:28px;height:28px;border-radius:50%;display:flex;align-items:center;justify-content:center;font-weight:700;font-size:15px;font-family:"JetBrains Mono",monospace;border:1px solid var(--line)}
.a p:first-child{margin-top:0}
.qdivider{height:1px;background:var(--line);margin:40px 0;border:none}

/* Exercises (expandable hint/answer) */
.ex{background:var(--panel);border:1px solid var(--line);border-radius:8px;padding:16px 18px;margin:14px 0}
.ex h4{margin:0 0 10px;font-size:15px;color:var(--cyan);font-weight:600}
.ex h4 .diff{color:var(--accent);font-family:"JetBrains Mono",monospace;font-size:12px;margin-right:6px}
.ex p{margin:6px 0}
.ex details{margin-top:10px;background:var(--panel2);border-radius:6px;border:1px solid var(--line)}
.ex details summary{cursor:pointer;padding:8px 14px;list-style:none;font-size:13px;color:var(--dim);user-select:none}
.ex details summary::-webkit-details-marker{display:none}
.ex details summary::before{content:"▸ ";color:var(--accent);font-family:monospace}
.ex details[open] summary::before{content:"▾ "}
.ex details[open] summary{color:var(--accent);border-bottom:1px solid var(--line)}
.ex details .body{padding:10px 14px;font-size:14px}
.ex details .body p:first-child{margin-top:0}
.ex details .body p:last-child{margin-bottom:0}

/* Misc */
ul.lst{padding-left:20px}
ul.lst li{margin:5px 0;color:var(--dim)}
kbd{background:var(--panel2);border:1px solid var(--line);padding:1px 6px;border-radius:3px;font-family:monospace;font-size:11px;color:var(--dim)}
.tag{display:inline-block;background:var(--panel2);color:var(--cyan);padding:1px 8px;border-radius:3px;font-size:11px;font-family:monospace;margin-right:6px}