:root{
	/* Light theme (default) */
	--bg:#ffffff;        /* page background */
	--panel:#f9fafb;     /* card/panel background */
	--text:#111827;      /* main text */
	--muted:#6b7280;     /* secondary text */
	--brand:#e75ea6;     /* accent 1 */
	--brand-2:#2563eb;   /* accent 2 */
	--border:#e5e7eb;    /* borders */
	--link:#2563eb;      /* link color */
	/* semantic accents */
	--good:#16a34a;      /* green */
	--bad:#dc2626;       /* red */
	--good-bg:#d3fde9;   /* green tint bg (light) */
	--bad-bg:#f8d5d5;    /* red tint bg (light) */
	/* feature accents */
	--acc1:#0ea5e9;    /* cyan/sky for 分散と多様性 */
	--acc1-bg:#e0f2fe; /* light sky tint */
	--acc2:#8b5cf6;    /* purple for レイヤー型暗号化 */
	--acc2-bg:#ede9fe; /* light purple tint */
	--acc3:#f59e0b;    /* amber for 公開仕様と研究 */
	--acc3-bg:#fef3c7; /* light amber tint */
}

/* Explicitly declare supported color schemes to prevent auto-inversion */
html{color-scheme: light dark}

@media (prefers-color-scheme: dark){
	:root{
		--bg:#0b0c10;
		--panel:#12141a;
		--text:#e8ecf1;
		--muted:#aab4c0;
		--brand:#e75ea6;
		--brand-2:#7aa2f7;
		--border:#222633;
		--link:#7aa2f7;
		--good:#34d399;    /* green (dark) */
		--bad:#f87171;     /* red (dark) */
		--good-bg:#0c1a14; /* deep green tint */
		--bad-bg:#1a0c0c;  /* deep red tint */
		/* feature accents (dark) */
		--acc1:#7dd3fc;    /* cyan (dark) */
		--acc1-bg:#0b1220;
		--acc2:#c4b5fd;    /* purple (dark) */
		--acc2-bg:#161225;
		--acc3:#fbbf24;    /* amber (dark) */
		--acc3-bg:#1f1505;
	}
}
*{box-sizing:border-box}
html,body{margin:0;padding:0;background:var(--bg);color:var(--text);font-family:system-ui,-apple-system,Segoe UI,Roboto,Helvetica,Arial,"Noto Sans JP",sans-serif;line-height:1.6}
.container{max-width:1024px;margin:0 auto;padding:0 20px}

/* Header */
.site-header__wrap{position:sticky;top:0;z-index:20;background:rgba(255,255,255,.9);backdrop-filter:saturate(180%) blur(8px);border-bottom:1px solid var(--border)}
.site-header{display:flex;align-items:center;height:64px;gap:16px}
.brand{display:flex;align-items:center;gap:10px;color:var(--text);text-decoration:none;font-weight:700}
.brand__logo{width:28px;height:28px;display:block}
.brand__name{white-space:nowrap}
.nav{margin-left:auto}
.nav ul{display:flex;list-style:none;margin:0;padding:0;gap:10px}
.nav a{display:block;padding:10px 12px;border-radius:8px;color:var(--text);text-decoration:none}
.nav a:hover{background:#eef2ff}
.nav a.active{background:linear-gradient(120deg,var(--brand),var(--brand-2));-webkit-background-clip:text;background-clip:text;color:transparent}
.nav-toggle{display:none;margin-left:auto;background:none;border:1px solid var(--border);border-radius:8px;padding:8px;cursor:pointer}
.nav-toggle span{display:block;width:20px;height:2px;background:var(--text);margin:3px 0}

/* Hero */
.hero{padding:56px 0;position:relative;overflow:hidden}
.hero::before{content:"";position:absolute;inset:-60px -40px auto -40px;height:320px;z-index:-1;filter:blur(30px) saturate(120%);
	background:radial-gradient(60% 60% at 20% 30%, rgba(231,94,166,.25), transparent 60%),
			  radial-gradient(50% 50% at 70% 20%, rgba(37,99,235,.25), transparent 60%),
			  radial-gradient(40% 40% at 60% 80%, rgba(16,185,129,.18), transparent 60%);
}
.hero h1{font-size:clamp(32px,5vw,52px);line-height:1.15;margin:0 0 12px}
.gradient-text{background:linear-gradient(120deg,var(--brand),var(--brand-2));-webkit-background-clip:text;background-clip:text;color:transparent}
.badge{display:inline-block;font-size:12px;letter-spacing:.02em;padding:6px 10px;border-radius:999px;border:1px solid var(--border);background:#ffffffcc;color:var(--text);margin-bottom:10px}
.hero h1{font-size:clamp(28px,4vw,40px);line-height:1.2;margin:0 0 10px}
.hero p{color:var(--muted);max-width:70ch}
.cta-row{display:flex;gap:16px;margin-top:16px}
.btn{display:inline-block;padding:10px 14px;border:1px solid var(--border);border-radius:12px;color:var(--text);text-decoration:none;background:#ffffff;transition:filter .15s ease,transform .05s ease,box-shadow .15s ease}
.btn:hover{background:#f3f4f6;filter:brightness(1.02)}
.btn:active{transform:translateY(1px)}
.btn:focus{outline:2px solid var(--brand-2);outline-offset:2px}
.btn.primary{background:linear-gradient(135deg,var(--brand),var(--brand-2));border:none;color:#ffffff}
/* large button */
.btn.lg{padding:12px 18px;font-size:16px;box-shadow:0 6px 16px rgba(2,6,23,.08)}
.btn.primary.lg,.btn.blue.lg,.btn.purple.lg,.btn.green.lg,.btn.orange.lg,.btn.pink.lg,.btn.red.lg{box-shadow:0 10px 24px rgba(37,99,235,.18)}
/* colorful variants */
.btn.pink{background:linear-gradient(135deg,#f472b6,#ec4899);border:none;color:#fff}
.btn.blue{background:linear-gradient(135deg,#60a5fa,#2563eb);border:none;color:#fff}
.btn.green{background:linear-gradient(135deg,#34d399,#10b981);border:none;color:#0b1f17}
.btn.orange{background:linear-gradient(135deg,#fbbf24,#f59e0b);border:none;color:#5b3a00}
.btn.purple{background:linear-gradient(135deg,#a78bfa,#8b5cf6);border:none;color:#fff}
.btn.red{background:linear-gradient(135deg,#fb7185,#ef4444);border:none;color:#fff}

/* Sections */
main section{padding:36px 0;border-top:1px solid var(--border)}
main section:first-of-type{border-top:none}
h2{font-size:22px;margin:0 0 14px}
h3{font-size:18px;margin:10px 0 8px}
p{font-size:15px;margin:0 0 12px}
li{font-size:15px;margin:6px 0}
.small{font-size:13px}
.small{font-size:13px}
.muted{color:var(--muted)}
ul,ol{margin:0 0 14px 20px}
.tip{background:#f3f4f6;border:1px solid var(--border);padding:10px 12px;border-radius:8px;margin:12px 0 16px}

/* Cards */
.cards{display:grid;grid-template-columns:repeat(auto-fit,minmax(220px,1fr));gap:18px;list-style:none;padding:0;margin:0}
.cards li{background:var(--panel);border:1px solid var(--border);padding:16px;border-radius:12px;box-shadow:0 1px 2px rgba(0,0,0,.06);transition:transform .15s ease,box-shadow .15s ease}
.cards li:hover{transform:translateY(-2px);box-shadow:0 6px 18px rgba(2,6,23,.08)}
/* spacing between stacked card lists */
.cards + .cards{margin-top:28px}
h2{font-size:22px;margin:0 0 12px}
.section-accent h2{position:relative;padding-top:6px}
.section-accent h2::after{content:"";display:block;width:56px;height:3px;margin-top:8px;background:linear-gradient(90deg,var(--brand),var(--brand-2));border-radius:2px}
/* green/red accents */
.cards li.card-green{background:var(--good-bg);border-left:4px solid var(--good)}
.cards li.card-red{background:var(--bad-bg);border-left:4px solid var(--bad)}
.cards li.card-green h3{color:var(--good)}
.cards li.card-red h3{color:var(--bad)}
.cards li.card-green ul li::marker{color:var(--good)}
.cards li.card-red ul li::marker{color:var(--bad)}
/* feature-specific accents */
.cards li.card-accent-1{background:var(--acc1-bg);border-left:4px solid var(--acc1)}
.cards li.card-accent-2{background:var(--acc2-bg);border-left:4px solid var(--acc2)}
.cards li.card-accent-3{background:var(--acc3-bg);border-left:4px solid var(--acc3)}
.cards li.card-accent-1 h3{color:var(--acc1)}
.cards li.card-accent-2 h3{color:var(--acc2)}
.cards li.card-accent-3 h3{color:var(--acc3)}

/* Principles */
.principles{padding-left:20px}

/* Footer */
.site-footer{border-top:1px solid var(--border);padding:22px 0;margin-top:40px;background:var(--panel)}
.site-footer p{margin:6px 0}

/* Responsive */
@media (max-width:720px){
	.nav-toggle{display:block}
	.nav{display:none}
	.nav.open{display:block;position:absolute;top:64px;right:0;left:0;background:var(--panel);border-bottom:1px solid var(--border)}
	.nav ul{flex-direction:column}
}

/* Dark mode explicit adjustments to avoid auto-invert clashes */
@media (prefers-color-scheme: dark){
	.site-header__wrap{background:rgba(18,20,26,.85)}
	.nav a:hover{background:rgba(255,255,255,.06)}
	.badge{background:rgba(18,20,26,.8)}
	.btn{background:#0f131a}
	.btn:hover{background:#161b22}
	.tip{background:#0f131a}
}

/* Terminal-like code blocks */
pre{position:relative;background:#0f172a;color:#e5e7eb;border:1px solid #0b1220;border-radius:12px;padding:32px 14px 12px;overflow:auto;font-family:ui-monospace,SFMono-Regular,Menlo,Consolas,"Liberation Mono",monospace;font-size:13.5px;line-height:1.6;margin:16px 0}
pre::before{content:"";position:absolute;top:0;left:0;right:0;height:24px;background:#0b1220;border-top-left-radius:12px;border-top-right-radius:12px;border-bottom:1px solid rgba(255,255,255,.06)}
pre::after{content:"●  ●  ●";position:absolute;top:2px;left:10px;font-size:12px;letter-spacing:6px;color:#ef4444;text-shadow:14px 0 0 #f59e0b,28px 0 0 #10b981}
pre code{background:none;display:block;white-space:pre}