:root{--blue:#174994;--deep:#102f60;--red:#d84c50;--yellow:#f7cf50;--ink:#203c62;--line:#bbd1ed;--surface:#f5f9ff;--font:"Hiragino Kaku Gothic ProN","Hiragino Sans",Meiryo,"Noto Sans CJK JP","Noto Sans JP",sans-serif}
*{box-sizing:border-box}html{scroll-behavior:smooth}body{margin:0;color:var(--ink);background:#f7faff;font-family:var(--font);font-size:16px;line-height:1.85}img{max-width:100%}a{color:var(--blue)}button{font:inherit}h1,h2,h3,p{overflow-wrap:anywhere}h1,h2,h3{color:var(--deep);font-family:var(--font);font-weight:900;line-height:1.48;letter-spacing:.01em;text-wrap:balance}h1{font-size:clamp(2.2rem,5vw,4.7rem)}h2{font-size:clamp(1.6rem,3vw,2.55rem)}h3{font-size:1.24rem}p{margin:0 0 1em}.skip-link{position:absolute;z-index:100;top:-100px;left:12px;padding:8px 15px;background:#fff;border:3px solid var(--blue)}.skip-link:focus{top:12px}:focus-visible{outline:4px solid #e75a51;outline-offset:3px}
.site-header{position:relative;z-index:3;background:#fff;border-bottom:2px solid #d8e6f7}.header-inner{max-width:1420px;margin:auto;min-height:76px;padding:11px clamp(20px,4vw,52px);display:flex;align-items:center;justify-content:space-between;gap:22px}.brand{color:var(--blue);font-size:1.19rem;font-weight:950;line-height:1.12;text-decoration:none;white-space:nowrap}.brand span{display:block;margin-top:4px;color:var(--red);font-size:.58rem;letter-spacing:.18em}.site-header nav{display:flex;flex-wrap:wrap;gap:8px 26px}.site-header nav a{text-decoration:none;font-size:.88rem;font-weight:900}.site-header nav a:hover{text-decoration:underline;text-underline-offset:5px}
.eyebrow,.section-kicker{display:inline-block;color:#bd3d42;font-weight:950;letter-spacing:.13em;font-size:.75rem}.home-hero,.lesson-hero{background:linear-gradient(117deg,#dfedff 0%,#f9fcff 54%,#fff1c7 100%);border-bottom:2px solid #d6e7f8;overflow:hidden}.home-hero-inner,.hero-inner{max-width:1420px;margin:auto;padding:clamp(45px,6vw,80px) clamp(20px,4vw,52px);display:grid;grid-template-columns:minmax(0,1.02fr) minmax(0,.98fr);gap:clamp(22px,4vw,62px);align-items:center}.hero-copy h1{margin:20px 0 20px;line-height:1.35}.home-hero h1{font-size:clamp(2.2rem,4.1vw,4rem)}.home-hero h1 em{font-style:normal;color:var(--blue)}.hero-copy p{font-size:clamp(1.03rem,1.5vw,1.2rem);font-weight:650;max-width:620px}.primary-link,.download{display:inline-flex;align-items:center;gap:18px;margin:16px 0 0;padding:12px 20px;border-radius:12px;background:var(--blue);color:#fff;font-weight:900;text-decoration:none;box-shadow:5px 5px 0 var(--yellow);transition:transform .2s,box-shadow .2s}.primary-link:hover,.download:hover{transform:translateY(-2px);box-shadow:6px 7px 0 var(--yellow)}.keywords{display:flex;gap:9px;flex-wrap:wrap;margin-top:30px}.keywords span{padding:5px 12px;border-radius:100px;background:#fff;border:1px solid #b4cae7;color:var(--deep);font-size:.8rem;font-weight:850}
.characters{position:relative;height:clamp(290px,31vw,405px);border:2px solid #a9c6e9;border-radius:30px;background:radial-gradient(circle at 52% 40%,#fff 0 29%,#e8f5ff 65%,#ffe6a7 100%);overflow:hidden;box-shadow:12px 12px 0 #d3e7fa}.characters:before{content:"";position:absolute;inset:auto 0 0;height:15%;background:linear-gradient(#e0eeff,#c5ddf6)}.characters img{position:absolute;bottom:0;height:auto;object-fit:contain;filter:drop-shadow(0 9px 8px #4266a332)}.character-a{left:-2%;width:32%}.character-teacher{left:27%;width:28%;bottom:4%!important}.character-robot{left:48%;width:27%;bottom:1%!important}.character-b{right:-2%;width:31%}.characters-small{height:330px}.characters-small:after{content:"AI";position:absolute;top:8px;right:22px;color:#1749941d;font-size:7rem;font-weight:950;line-height:1}
.intro-band,.home-section,.how-section,.home-message{max-width:1360px;margin:auto;padding-left:clamp(20px,4vw,52px);padding-right:clamp(20px,4vw,52px)}.intro-band{display:grid;grid-template-columns:1.2fr 1fr;gap:25px;align-items:center;padding-top:62px;padding-bottom:62px}.intro-band h2{margin:8px 0}.intro-band p{font-weight:650}.mini-route{display:flex;flex-wrap:wrap;gap:12px}.mini-route span{flex:1 1 110px;padding:16px 12px;background:#fff;border:2px solid var(--line);border-radius:14px;color:var(--blue);font-weight:900;text-align:center}.mini-route span:nth-child(2){background:#fff5d6}.home-groups{scroll-margin-top:20px}.home-section{padding-top:34px;padding-bottom:45px}.home-heading{margin-bottom:22px}.home-heading h2{margin:5px 0}.card-grid{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:20px}.topic-card{display:grid;grid-template-columns:170px minmax(0,1fr);overflow:hidden;border:2px solid #a9c3e7;border-radius:19px;background:#fff;box-shadow:5px 5px 0 #e1ecfa}.card-art{position:relative;display:flex;align-items:center;background:linear-gradient(145deg,#e0edff,#fff3c7);overflow:hidden}.card-art img{width:145%;max-width:none;transform:translateX(-13%);height:160px;object-fit:contain}.card-art span{position:absolute;top:3px;left:8px;color:#194b9024;font-size:4.8rem;font-weight:950;line-height:1}.card-copy{min-width:0;padding:19px 21px}.card-copy small{color:var(--red);font-size:.71rem;font-weight:950;letter-spacing:.1em}.card-copy h3{margin:4px 0 6px;font-size:1.28rem}.card-copy p{font-size:.86rem;line-height:1.66;min-height:2.6em}.card-copy a{font-weight:900;text-underline-offset:4px}.how-section{scroll-margin-top:25px;padding-top:55px;padding-bottom:55px}.how-section h2{margin:5px 0 21px}.how-grid{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:17px}.how-grid>div{padding:22px;border:2px solid var(--line);border-radius:19px;background:#fff}.how-grid strong{color:var(--red);font-size:1.4rem}.how-grid h3{margin:5px 0}.how-grid p{font-size:.88rem}.home-message{display:flex;align-items:center;gap:15px;margin-top:25px;margin-bottom:70px}.home-message img{width:80px;height:80px;object-fit:contain}.home-message p{margin:0;padding:16px 22px;background:#fff;border:2px solid var(--line);border-radius:16px}.home-message strong{color:var(--blue)}
.lesson-hero .hero-inner{padding-top:50px;padding-bottom:55px}.lesson-hero h1{font-size:clamp(2.25rem,4.1vw,3.8rem)}.lesson-layout{max-width:1390px;margin:0 auto;padding:60px clamp(20px,4vw,52px) 90px;display:grid;grid-template-columns:215px minmax(0,1fr);gap:clamp(24px,4vw,60px)}.side-nav{align-self:start;position:sticky;top:18px;display:flex;flex-direction:column;gap:10px;padding:19px 17px;background:#fff;border:2px solid #c5d9f0;border-radius:18px}.side-nav strong{margin-bottom:6px;color:var(--red);font-weight:950}.side-nav a{padding:5px 8px;border-radius:8px;color:var(--deep);font-size:.84rem;font-weight:850;text-decoration:none}.side-nav a:hover{background:#edf5ff}.lesson-main{min-width:0}.goal-card,.lesson-section,.colab-card,.coffee{scroll-margin-top:25px}.goal-card{padding:25px 28px;background:#fff;border:3px solid var(--blue);border-radius:19px;box-shadow:8px 8px 0 #dceaff}.goal-card h2{margin:6px 0 9px;font-size:1.8rem}.goal-card>p{font-size:1.04rem;font-weight:800}.term-row{display:flex;align-items:center;flex-wrap:wrap;gap:8px;margin-top:20px;padding-top:16px;border-top:1px solid #dbe7f5}.term-row>strong{color:var(--blue);font-size:.82rem}.term{padding:6px 10px;border:1px solid #a8c5e9;border-radius:9px;background:#edf5ff;color:var(--deep);font-size:.8rem;font-weight:850;cursor:pointer}.term span{margin-left:5px;color:var(--red)}.term:hover{background:#d9eafa}.lesson-section{margin-top:65px}.section-heading h2{margin:6px 0 12px}.section-heading p{font-weight:650}.talk{display:grid;gap:12px;margin:25px 0}.bubble{display:grid;grid-template-columns:62px minmax(0,1fr);gap:14px;align-items:center;padding:12px 17px;border-radius:18px;border:2px solid #b6cfeb;background:#fff}.bubble.student-a{margin-right:7%;background:#f1f7ff}.bubble.teacher{margin-left:4%;margin-right:3%;background:#fff9e5;border-color:#e8cd78}.bubble.student-b{margin-left:7%;background:#eef8f5;border-color:#afd5c7}.bubble img{width:62px;height:62px;object-fit:contain}.bubble strong{color:var(--blue);font-size:.87rem}.bubble p{margin:2px 0 0;font-size:.93rem;font-weight:650}.lesson-figure{margin:27px 0;padding:19px;background:#fff;border:2px solid var(--blue);border-radius:20px;box-shadow:7px 7px 0 #e1ecfb}.lesson-figure img{display:block;width:100%;height:auto;border-radius:13px}.lesson-figure figcaption{margin:14px 0 0;padding-top:11px;border-top:1px solid #d9e6f5;color:#476283;font-size:.81rem;font-weight:750}.explain-box{padding:15px 20px;border-left:5px solid var(--yellow);background:#fff9df;border-radius:0 13px 13px 0}.explain-box strong{color:var(--deep)}.explain-box p{margin:5px 0 0;font-size:.92rem}.code-title{display:flex;align-items:baseline;justify-content:space-between;gap:12px;margin-top:27px;margin-bottom:6px}.code-title strong{color:var(--blue)}.code-title span{color:#637b99;font-size:.79rem;font-weight:800}.code-block{max-width:100%;overflow:auto;margin:12px 0;padding:20px 22px;border-radius:15px;background:#102b54;color:#fff;font-family:Consolas,"Cascadia Code",monospace;font-size:.89rem;line-height:1.68;white-space:pre;tab-size:4}.result{display:flex;flex-wrap:wrap;gap:8px 18px;padding:14px 17px;border:2px solid #b8d3f0;background:#eaf4ff;border-radius:12px}.result strong{color:var(--blue);white-space:nowrap}.result span{font-weight:850}.why{margin:16px 0 0;padding:0 0 0 13px;border-left:4px solid var(--red);font-weight:650}.why strong{color:var(--red)}.quiz{padding:22px;border:2px solid var(--blue);border-radius:18px;background:#fff}.quiz>strong{display:block;margin-bottom:15px;color:var(--deep);font-size:1.13rem}.quiz-options{display:flex;flex-wrap:wrap;gap:10px}.quiz-options button{padding:9px 14px;border:2px solid #a9c5e7;border-radius:9px;background:#edf5ff;color:var(--deep);font-weight:850;cursor:pointer}.quiz-options button:hover{background:#dcecff}.quiz-options button.correct{border-color:#15815f;background:#dbf7eb}.quiz-options button.wrong{border-color:#d35657;background:#ffe9e6}.quiz-feedback{min-height:1.5em;margin:16px 0 0;font-weight:800}.colab-card{margin-top:60px;padding:26px 29px;border:3px solid #d0a527;border-radius:20px;background:linear-gradient(120deg,#fff5cf,#fffdf4)}.colab-card h2{margin:6px 0 10px}.colab-card>p{font-weight:650}.colab-actions{display:flex;gap:12px;flex-wrap:wrap;align-items:center}.download{margin:8px 0}.colab-link{display:inline-flex;align-items:center;padding:10px 16px;border:2px solid var(--blue);border-radius:11px;background:#fff;font-weight:900;text-decoration:none}.colab-note{margin:14px 0 0!important;font-size:.81rem}.coffee{margin-top:40px;padding:22px 26px;border:2px solid #e2c264;border-radius:20px;background:#fff9e5}.coffee h2{margin:5px 0 12px;font-size:1.55rem}.coffee-inner{display:flex;align-items:center;gap:14px}.coffee-inner img{width:85px;height:85px;object-fit:contain}.coffee-inner p{margin:0;font-weight:700}.coffee-inner strong{color:var(--blue)}.closing{display:flex;align-items:center;gap:13px;margin:40px 0 20px}.closing img{width:72px;height:72px;object-fit:contain}.closing p{margin:0;padding:13px 17px;border:2px solid var(--line);border-radius:14px;background:#fff;font-size:.91rem}.closing strong{color:var(--blue)}.prev-next{display:flex;justify-content:space-between;gap:12px}.prev-next a{padding:9px 13px;border:2px solid var(--blue);border-radius:9px;background:#fff;color:var(--deep);font-weight:900;text-decoration:none}.prev-next a:last-child{background:var(--blue);color:#fff}.site-footer{display:flex;flex-direction:column;gap:1px;padding:34px 25px;background:#112f5f;color:#fff;text-align:center;font-size:.8rem}.site-footer strong{font-size:1.2rem;letter-spacing:.1em}.site-footer small{margin-top:6px}.term-dialog{width:min(92vw,430px);padding:0;border:2px solid var(--blue);border-radius:15px;box-shadow:0 15px 35px #102f6040}.term-dialog::backdrop{background:#0d234f91}.dialog-top{display:flex;align-items:center;justify-content:space-between;gap:15px;padding:14px 19px;background:#e7f2ff}.dialog-top h2{margin:0;font-size:1.3rem}.dialog-close{border:0;background:#fff;border-radius:8px;width:35px;height:35px;color:var(--blue);font-size:1.25rem;font-weight:900;cursor:pointer}.term-description{margin:0;padding:20px;font-weight:700}
@media(max-width:1100px){.card-grid{grid-template-columns:1fr}.topic-card{grid-template-columns:180px minmax(0,1fr)}}
@media(max-width:820px){.home-hero-inner,.hero-inner{grid-template-columns:1fr}.characters{width:min(100%,640px);justify-self:center}.intro-band{grid-template-columns:1fr}.lesson-layout{display:block}.side-nav{position:static;flex-direction:row;flex-wrap:wrap;margin-bottom:30px}.side-nav strong{width:100%}.characters-small{height:280px}.how-grid{grid-template-columns:1fr}}
@media(max-width:560px){body{font-size:15px}.header-inner{align-items:flex-start;min-height:0;flex-direction:column;gap:8px;padding-top:12px;padding-bottom:12px}.site-header nav{gap:6px 15px}.characters{height:260px;border-radius:22px}.characters-small{height:230px}.home-hero-inner,.hero-inner{padding-top:38px;padding-bottom:40px}.home-hero h1,.lesson-hero h1{font-size:clamp(2.05rem,10vw,3rem)}.mini-route{display:grid;grid-template-columns:1fr}.topic-card{display:block}.card-art{height:150px;justify-content:center}.card-art img{width:100%;transform:none;height:145px}.goal-card,.colab-card{padding:20px}.bubble,.bubble.teacher,.bubble.student-a,.bubble.student-b{margin-left:0;margin-right:0;grid-template-columns:48px minmax(0,1fr);padding:10px}.bubble img{width:48px;height:48px}.coffee-inner{align-items:flex-start}.coffee-inner img{width:58px;height:58px}.prev-next a{font-size:.8rem}.code-block{font-size:.79rem;padding:15px}}
@media(prefers-reduced-motion:reduce){html{scroll-behavior:auto}.primary-link,.download{transition:none}}
@media print{.site-header,.side-nav,.prev-next,.colab-actions,.term-row{display:none}.lesson-layout{padding:0}.lesson-figure,.goal-card{box-shadow:none}.lesson-section{break-inside:avoid}}

/* Individual transparent lesson illustrations and Python-course dialogue style. */
.hero-illustration-wrap{min-width:0;display:grid;place-items:center;align-self:stretch}
.hero-illustration-wrap img{display:block;width:100%;height:auto;max-height:430px;object-fit:contain;filter:drop-shadow(0 12px 12px #2a4c8526)}
.lesson-hero .hero-illustration-wrap img{max-height:345px}
.card-art{justify-content:center;min-height:175px}
.card-art img{width:100%;max-width:100%;height:172px;transform:none;object-fit:contain;padding:8px;filter:drop-shadow(0 5px 4px #2a4c8523)}
.card-art span{top:6px;left:9px;padding:1px 7px;border-radius:7px;background:#ffffffdd;color:var(--blue);font-size:.82rem;line-height:1.3;z-index:1}
.talk{gap:13px;margin:28px 0}
.bubble,.bubble.student-a,.bubble.student-b,.bubble.teacher{grid-template-columns:68px minmax(0,1fr);align-items:start;gap:13px;max-width:740px;margin:0;padding:0;border:0;border-radius:0;background:transparent}
.bubble>img{width:68px;height:68px;object-fit:contain;object-position:center top;border:3px solid var(--blue);border-radius:50%;background:#fff}
.bubble.student-a>img{border-color:#ec8178;background:#fff0e9}
.bubble.student-b>img{border-color:#81a8e7;background:#e9f3ff}
.bubble.teacher>img{border-color:#e4bd54;background:#fff8da}
.bubble>div{min-width:0;padding:13px 19px;background:#fff;border:2px solid var(--line);border-radius:8px 18px 18px 18px;box-shadow:4px 4px 0 #e7effc}
.bubble.student-a>div{border-color:#f5c5bf}
.bubble.student-b>div{border-color:#bdd5f4}
.bubble.teacher>div{border-color:#efd796;background:#fffefa}
.bubble strong{display:block;color:var(--blue);font-size:.82rem;font-weight:950}
.bubble p{margin:2px 0 0;font-size:.95rem;line-height:1.75}
.glossary-card{scroll-margin-top:25px;margin-top:42px;padding:25px 28px;border:2px solid #b8d0ed;border-radius:19px;background:#fff}
.glossary-card h2{margin:5px 0 8px;font-size:1.7rem}
.glossary-card>p{font-size:.91rem}
.glossary-card dl{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:10px;margin:18px 0 0}
.glossary-entry{padding:12px 15px;border-radius:11px;background:#edf5ff}
.glossary-entry dt{color:var(--blue);font-weight:950}
.glossary-entry dd{margin:3px 0 0;font-size:.87rem;line-height:1.65}
@media(max-width:560px){.card-art img{height:150px}.bubble,.bubble.student-a,.bubble.student-b,.bubble.teacher{grid-template-columns:52px minmax(0,1fr);gap:9px}.bubble>img{width:52px;height:52px}.bubble>div{padding:10px 13px}.glossary-card{padding:20px}.glossary-card dl{grid-template-columns:1fr}}
.lesson-hero h1{overflow-wrap:normal;word-break:keep-all}
.home-hero h1 em{white-space:nowrap}
@media(min-width:1101px){.topic-card{grid-template-columns:200px minmax(0,1fr)}.card-art img{height:185px}}
@media(max-width:560px){.home-hero h1{font-size:clamp(1.7rem,7.8vw,2.2rem)}.lesson-hero h1{font-size:clamp(1.85rem,8vw,2.7rem)}.card-art{height:180px}.card-art img{height:175px}}
.intro-band h2{overflow-wrap:normal;word-break:keep-all;text-wrap:normal}
.group-note{max-width:850px;margin:5px 0 0;font-weight:650}
.figure-guide{display:flex;align-items:center;gap:13px;margin-top:13px;padding:11px 14px;border:1px solid #c5d9f0;border-radius:14px;background:#f5f9ff}
.figure-guide img{flex:none;width:60px;height:60px;object-fit:contain;border:2px solid #b6cfeb;border-radius:50%;background:#fff}
.figure-guide p{margin:0;font-size:.9rem;font-weight:700;line-height:1.65}
.figure-guide strong{color:var(--blue);font-weight:950}
@media(max-width:560px){.lesson-figure{padding:10px}.figure-guide{align-items:flex-start;gap:9px;padding:9px}.figure-guide img{width:48px;height:48px}.figure-guide p{font-size:.85rem}}

/* NumPy: show the operands, not only the answer. */
.array-result{align-items:flex-start}
.array-result pre{min-width:0;max-width:100%;overflow:auto;margin:0;font:800 .92rem/1.55 Consolas,"Cascadia Code",monospace;white-space:pre}
.array-explainer{margin-top:28px;padding:24px;border:2px solid #a9c6e9;border-radius:18px;background:linear-gradient(135deg,#f5faff,#fffdf4)}
.array-explainer h3{margin:0 0 15px;font-size:1.34rem;line-height:1.5}
.array-explainer .talk{margin:16px 0 23px}
.array-equation{display:flex;align-items:center;justify-content:center;flex-wrap:wrap;gap:8px;margin:20px 0;padding:17px 10px;border-radius:14px;background:#fff}
.array-grid-wrap{padding:10px;border:2px solid #b9d1ee;border-radius:12px;background:#f1f7ff;text-align:center}
.array-grid-wrap>strong{display:block;margin-bottom:7px;color:var(--blue);font-size:.8rem}
.array-grid-wrap table{margin:auto;border-spacing:5px}
.array-grid-wrap td{min-width:37px;padding:4px 7px;border-radius:7px;background:#fff;color:var(--deep);font:900 1rem/1.5 Consolas,"Cascadia Code",monospace;text-align:center}
.array-grid-wrap.array-answer{border-color:#d2a828;background:#fff8df}
.array-operator{color:var(--red);font-size:1.55rem;font-weight:950}
.array-steps{display:grid;gap:7px;margin:14px 0}
.array-steps p{margin:0;padding:9px 12px;border-left:4px solid var(--yellow);border-radius:4px;background:#fff;font-weight:750}
.array-steps strong{color:var(--blue)}
.array-shape-note{margin:18px 0;padding:13px 16px;border-radius:11px;background:#e7f1ff;font-weight:680}
.array-compare{padding:16px 19px;border-radius:12px;background:#fff}
.array-compare>strong{color:var(--blue)}
.array-compare ul{margin:8px 0;padding-left:1.3em}
.array-compare li{margin:5px 0}
.array-compare p{margin:9px 0 0}
.array-compare code{padding:1px 4px;border-radius:3px;background:#eaf3ff;font-size:.9em}
@media(max-width:560px){.array-explainer{padding:18px 12px}.array-equation{flex-direction:column;gap:8px}.array-grid-wrap{width:min(100%,260px)}.array-grid-wrap td{min-width:42px}}