:root{color-scheme:light dark;--ink:#252d2c;--muted:#65706c;--paper:#fffefa;--canvas:#f4f3ed;--line:#d8d9d0;--teal:#286c63;--teal-soft:#eaf2ef;
--link:#245e58;--code-bg:#fbfaf5;--code-ink:#252d2c;--tab-bg:#ecebe3;
--term-bg:#1f2726;--term-bar:#2d3836;--term-ink:#e8ece8;--term-prompt:#7fd1b9;--term-muted:#9fb0aa;
--k:#a23b72;--t:#1d6f8c;--s:#2f7d32;--c:#7a857f;--n:#b4561e;--d:#7b4fa3;
--py-bg:#eef1f8;--py-line:#4a6fa5;--why-bg:#eaf2ef;--why-line:#286c63;--trap-bg:#f8eee3;--trap-line:#b4651f;--note-bg:#f1f0ea;--note-line:#8a8f86;
font-family:system-ui,-apple-system,"Segoe UI","Hiragino Sans","Yu Gothic UI","Noto Sans JP",sans-serif;font-synthesis:none}
@media(prefers-color-scheme:dark){:root{--ink:#e4e9e5;--muted:#9aa7a1;--paper:#1b2221;--canvas:#141a19;--line:#34403d;--teal:#6cc3ae;--teal-soft:#1f2f2c;
--link:#8fd3c1;--code-bg:#161d1c;--code-ink:#e4e9e5;--tab-bg:#232d2b;
--term-bg:#0f1514;--term-bar:#222c2a;
--k:#e58ab8;--t:#6cc1de;--s:#8fd18f;--c:#7f8c86;--n:#f0a070;--d:#c39be8;
--py-bg:#1d2433;--py-line:#7a9ad0;--why-bg:#1f2f2c;--why-line:#6cc3ae;--trap-bg:#33271b;--trap-line:#e0963f;--note-bg:#232927;--note-line:#7d8a84}}
*{box-sizing:border-box}
html{scroll-behavior:smooth;-webkit-text-size-adjust:100%}
body{margin:0;background:var(--canvas);color:var(--ink);font-size:17px;line-height:1.85;line-break:strict;word-break:normal;overflow-wrap:anywhere;overflow-x:hidden}
a{color:var(--link);text-underline-offset:.18em}
a:hover{text-decoration-thickness:2px}
:focus-visible{outline:3px solid var(--n);outline-offset:3px}
button{font:inherit}
code{font-family:ui-monospace,SFMono-Regular,Consolas,"Cascadia Mono",monospace;font-size:.9em;padding:.08em .35em;border-radius:4px;background:var(--teal-soft)}
.topbar{position:sticky;top:0;z-index:20;display:flex;align-items:center;justify-content:space-between;gap:1rem;min-height:48px;padding:0 16px;background:var(--paper);border-bottom:1px solid var(--line)}
.topbar .brand{font-family:Georgia,"Times New Roman",serif;font-weight:700;color:var(--ink);text-decoration:none;font-size:1.05rem}
.topbar nav a{font-size:.9rem;padding:.6rem .2rem}
.layout{display:block}
.main{width:min(calc(100% - 32px),72ch);margin:0 auto;padding:2rem 0 4rem;min-width:0}
.chap-head{margin-bottom:1.5rem;padding-bottom:1.2rem;border-bottom:1px solid var(--line)}
.chap-no{margin:0;color:var(--teal);font-weight:700;letter-spacing:.06em;font-size:.9rem}
.chap-head h1,.book-head h1{margin:.2rem 0 .6rem;font-family:Georgia,"Times New Roman","Hiragino Mincho ProN","Yu Mincho",serif;font-weight:500;line-height:1.3;font-size:clamp(1.8rem,5vw,2.5rem);letter-spacing:-.01em}
.summary,.subtitle{margin:0;color:var(--muted)}
.main h2{margin:2.4em 0 .6em;font-family:Georgia,"Times New Roman","Hiragino Mincho ProN","Yu Mincho",serif;font-weight:500;font-size:1.55rem;line-height:1.4;scroll-margin-top:64px}
.main h3{margin:1.9em 0 .5em;font-size:1.2rem;line-height:1.45;scroll-margin-top:64px}
.secnum{display:inline-block;margin-right:.6em;color:var(--teal);font-family:system-ui,sans-serif;font-size:.8em;font-variant-numeric:tabular-nums}
.main p{margin:.9em 0}
.main ul,.main ol{padding-left:1.5em}
.main li{margin:.25em 0}
.table-wrap{overflow-x:auto;margin:1.2rem 0}
table{border-collapse:collapse;min-width:100%;font-size:.95rem;line-height:1.6}
th,td{padding:.45rem .7rem;border:1px solid var(--line);text-align:left;vertical-align:top}
th{background:var(--teal-soft)}
/* outline */
.outline{display:none}
.outline-m{margin:0 0 1.5rem;padding:.4rem .9rem;border:1px solid var(--line);background:var(--paper);border-radius:6px}
.outline-m summary{cursor:pointer;color:var(--teal);font-weight:650;min-height:36px;display:flex;align-items:center}
.outline-m ol,.outline ol{list-style:none;margin:.3rem 0 .5rem;padding:0}
.outline a{display:block;padding:.25rem .5rem;border-left:2px solid transparent;color:var(--muted);text-decoration:none;font-size:.88rem;line-height:1.5}
.outline-m a{display:block;padding:.4rem 0;text-decoration:none;font-size:.95rem}
.outline a.on{color:var(--ink);border-left-color:var(--teal);background:var(--teal-soft)}
.outline a:hover{color:var(--ink)}
.outline-h{margin:0 0 .4rem;font-size:.78rem;color:var(--muted);letter-spacing:.06em}
@media(min-width:1100px){
.layout{display:grid;grid-template-columns:minmax(200px,260px) minmax(0,72ch);justify-content:center;column-gap:3rem;padding:0 1.5rem}
.layout .main{width:auto;margin:0}
.outline{display:block;position:sticky;top:64px;align-self:start;max-height:calc(100vh - 80px);overflow-y:auto;padding:2rem 0}
.outline-m{display:none}
}
/* code */
.code{margin:1.3rem 0;border:1px solid var(--line);border-radius:6px;overflow:hidden;background:var(--code-bg)}
.code-tab{display:flex;align-items:center;justify-content:space-between;gap:.5rem;padding:0 .5rem 0 .9rem;min-height:36px;background:var(--tab-bg);border-bottom:1px solid var(--line);font-size:.82rem}
.code-tab .fname{font-family:ui-monospace,Consolas,monospace;font-weight:650}
.code-tab-plain{color:var(--muted);text-transform:lowercase}
pre{margin:0;padding:.9rem 1rem;overflow-x:auto;tab-size:4;-webkit-overflow-scrolling:touch}
pre code{display:block;padding:0;background:none;font-size:.9rem;line-height:1.7;white-space:pre;color:var(--code-ink)}
.copy{border:1px solid var(--line);background:var(--paper);color:var(--muted);border-radius:4px;font-size:.75rem;padding:.2rem .6rem;cursor:pointer;min-height:26px}
.copy:hover{color:var(--ink)}
.copy.done{color:var(--teal);border-color:var(--teal)}
.k{color:var(--k);font-weight:600}.t{color:var(--t)}.s{color:var(--s)}.c{color:var(--c);font-style:italic}.n{color:var(--n)}.d{color:var(--d)}
/* terminal */
.term{margin:1.3rem 0;border-radius:8px;overflow:hidden;background:var(--term-bg);color:var(--term-ink);border:1px solid #0000}
.term-bar{display:flex;align-items:center;gap:.7rem;padding:0 .5rem 0 .8rem;min-height:34px;background:var(--term-bar);font-size:.8rem;color:var(--term-muted)}
.term-bar .dots{display:flex;gap:6px}
.term-bar .dots i{width:10px;height:10px;border-radius:50%;background:#ff5f57}
.term-bar .dots i:nth-child(2){background:#febc2e}.term-bar .dots i:nth-child(3){background:#28c840}
.term-title{flex:1;text-align:center}
.term .copy{background:transparent;color:var(--term-muted);border-color:#ffffff30}
.term .copy:hover{color:#fff}
.term-body{font:.88rem/1.65 ui-monospace,SFMono-Regular,Consolas,"Cascadia Mono",monospace;white-space:pre-wrap;overflow-wrap:anywhere;color:var(--term-ink)}
.term-body .prompt{color:var(--term-prompt);user-select:none}
.term-body .cmd{font-weight:700;color:#fff}
.term-body .out{color:var(--term-ink)}
.term-body .out.pending{color:#e0b060;font-style:italic}
/* admonition */
.adm{margin:1.5rem 0;padding:.2rem 1.1rem .4rem;border-left:4px solid var(--note-line);background:var(--note-bg);border-radius:0 6px 6px 0}
.adm>:first-child{margin-top:.6rem}
.adm-label{margin:.7rem 0 .2rem!important;font-weight:700;font-size:.9rem;letter-spacing:.02em}
.adm-title{margin-left:.6em;font-weight:600}
.adm-python{background:var(--py-bg);border-color:var(--py-line)}.adm-python .adm-label{color:var(--py-line)}
.adm-why{background:var(--why-bg);border-color:var(--why-line)}.adm-why .adm-label{color:var(--why-line)}
.adm-trap{background:var(--trap-bg);border-color:var(--trap-line)}.adm-trap .adm-label{color:var(--trap-line)}
.adm-note .adm-label{color:var(--muted)}
.adm .code,.adm .term{margin:1rem 0}
/* figure */
.fig{margin:1.8rem 0}
.fig-media{position:relative;display:inline-block;max-width:100%;line-height:0;border:1px solid var(--line);border-radius:6px;overflow:hidden;background:var(--paper)}
.fig-media img{display:block;max-width:100%;height:auto}
.fig-svg{display:block;line-height:1.4;color:var(--ink);padding:.5rem}
.fig-media:has(.fig-svg),.fig-media:has(.fig-missing){display:block}
.fig-svg svg{display:block;width:100%;max-width:680px;height:auto;margin:0 auto}
.fig-missing{display:flex;align-items:center;justify-content:center;width:100%;aspect-ratio:16/9;border:2px dashed var(--line);color:var(--muted);line-height:1.5;font-size:.95rem;text-align:center;padding:1rem}
.callout{position:absolute;transform:translate(-50%,-50%);display:grid;place-items:center;width:1.7rem;height:1.7rem;border-radius:50%;background:#d6452d;color:#fff;font:700 .85rem/1 system-ui,sans-serif;border:2px solid #fff;box-shadow:0 1px 4px #0006}
figcaption{margin-top:.6rem;color:var(--muted);font-size:.9rem;line-height:1.6}
.fig-no{font-weight:700;color:var(--ink);margin-right:.4em}
/* quiz / exercise */
.quiz,.exercise{margin:2.5rem 0;padding:.3rem 1.2rem 1rem;border:1px solid var(--line);border-top:4px solid var(--teal);border-radius:6px;background:var(--paper)}
.main .boxhead{margin:.8rem 0 .6rem;font-family:system-ui,sans-serif;font-size:1.15rem;font-weight:700;color:var(--teal)}
.boxhead .ex-title{margin-left:.5em;color:var(--ink)}
.quiz ol{margin:0}
.quiz .q{font-weight:650;margin:.8em 0 .3em}
details.q-x,.quiz details,.exercise details{margin:.5rem 0 1rem}
.quiz summary,.exercise summary{cursor:pointer;color:var(--teal);font-weight:650;min-height:36px;display:flex;align-items:center}
.a{padding:.1rem 1rem;border-left:3px solid var(--line)}
/* pager */
.pager{display:flex;justify-content:space-between;gap:1rem;margin-top:3rem;padding-top:1.2rem;border-top:1px solid var(--line)}
.pager a{display:grid;gap:.1rem;max-width:48%;text-decoration:none;padding:.5rem .8rem;border:1px solid var(--line);border-radius:6px;background:var(--paper)}
.pager .next{text-align:right;margin-left:auto}
.pager .pl{font-size:.78rem;color:var(--muted)}
.pager .pt{font-weight:650;font-size:.95rem}
/* home */
.book-head{padding-bottom:1.5rem;border-bottom:1px solid var(--line)}
.book-head .desc{margin:1rem 0 0}
.ver{color:var(--muted);font-size:.9rem;padding:.6rem .9rem;border-left:3px solid var(--teal);background:var(--teal-soft)}
.part h2{font-size:1.3rem}
.part-intro{color:var(--muted);margin:.2em 0 .8em}
ol.chapters{list-style:none;padding:0;margin:0;border-top:1px solid var(--line)}
ol.chapters li{margin:0;padding:.7rem 0;border-bottom:1px solid var(--line)}
ol.chapters .cn{color:var(--teal);font-weight:700;margin-right:.4em;font-variant-numeric:tabular-nums}
ol.chapters .ct{font-weight:650}
ol.chapters a{text-decoration:none;display:block}
ol.chapters a:hover .ct{text-decoration:underline}
ol.chapters .sum{display:block;color:var(--muted);font-size:.9rem;line-height:1.6}
ol.chapters .soon{color:var(--muted)}
.badge{margin-left:.7em;padding:.05em .6em;border:1px solid var(--line);border-radius:99px;font-size:.75rem}
@media(max-width:760px){body{font-size:16px}.main h2{font-size:1.4rem}.pager a{max-width:49%}}
@media print{.topbar,.outline,.copy{display:none}}
.prompt-bash{color:var(--term-ink)}.p-host{color:#8ae234;font-weight:700}.p-path{color:#729fcf;font-weight:700}