/* -------- Root & Reset -------- */
:root {
    --bg: #0b0d12;
    --bg-2: #0f1117;
    --text: #e5e7eb;
    --muted: #9aa4b2;
    --line: #cbd5e1;
    --surface: rgba(255,255,255,0.06);
    --surface-2: rgba(255,255,255,0.10);
    --primary-500: #0ea5e9; /* sky-500 */
    --primary-600: #0284c7;
    --accent-500: #22d3ee;  /* cyan-400 */
    --radius: 18px;
    --shadow: 0 10px 30px rgba(0,0,0,.35);
}

* { box-sizing: border-box; }
html, body { height: 100%; scroll-behavior: smooth; }
body {
    margin: 0;
    font: 16px/1.6 ui-sans-serif, system-ui, -apple-system, Segoe UI, Roboto, "Helvetica Neue", Inter, Arial, "Noto Sans", "Apple Color Emoji", "Segoe UI Emoji";
    color: var(--text);
    background:
    radial-gradient(1200px 600px at 85% -10%, rgba(34,211,238,.08), transparent 60%),
    radial-gradient(1200px 600px at 10% 110%, rgba(14,165,233,.08), transparent 60%),
    linear-gradient(180deg, var(--bg), var(--bg-2));
}

/* Light mode */
@media (prefers-color-scheme: light) {
    :root {
        --bg: #f8fafc;
        --bg-2: #ffffff;
        --text: #0f172a;
        --muted: #475569;
        --line: #64748b;
        --surface: rgba(15,23,42,0.05);
        --surface-2: rgba(15,23,42,0.08);
    }
}
body.theme-dark { /* toggled */
    --bg: #0b0d12; --bg-2:#0f1117; --text:#e5e7eb; --muted:#9aa4b2; --line:#cbd5e1;
    --surface: rgba(255,255,255,0.06); --surface-2: rgba(255,255,255,0.10);
}

/* -------- Utilities -------- */
.container { width: min(1100px, 92%); margin: 0 auto; }
.section { padding: 80px 0; position: relative; }
.section-head { text-align: center; margin-bottom: 36px; }
.section-title { font-size: clamp(28px, 3.5vw, 40px); margin: 0 0 8px; letter-spacing: .2px; }
.section-sub { margin: 0; color: var(--muted); }
.grid { display: grid; gap: 22px; }
.grid--2 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
.grid--3 { grid-template-columns: repeat(3, minmax(0, 1fr)); }
.grid--4 { grid-template-columns: repeat(4, minmax(0, 1fr)); }
@media (max-width: 980px) { .grid--3, .grid--4 { grid-template-columns: 1fr 1fr; } }
@media (max-width: 720px) { .grid--2, .grid--3, .grid--4 { grid-template-columns: 1fr; } }

.card {
    background: var(--surface);
    border: 1px solid rgba(255,255,255,.08);
    backdrop-filter: blur(6px);
    border-radius: var(--radius);
    padding: 22px 22px;
    box-shadow: var(--shadow);
}
.card--soft { background: var(--surface-2); }
.card--hover { transition: transform .25s ease, background .25s ease; }
.card--hover:hover { transform: translateY(-6px); background: var(--surface-2); }

.list { margin: 10px 0 0 16px; padding: 0; }
.list li { margin: 6px 0; }

.chips, .tags {
    display: flex; flex-wrap: wrap; gap: 8px; margin: 12px 0 0;
}
.chips li, .tags span {
    font-size: 12px; padding: 6px 10px; border-radius: 999px;
    background: rgba(14,165,233,.12); color: var(--text); border: 1px solid rgba(14,165,233,.25);
}

/* -------- Header / Nav -------- */
.site-header {
    position: sticky; top: 0; z-index: 50; backdrop-filter: blur(8px);
    background: linear-gradient(180deg, rgba(0,0,0,.35), transparent);
    border-bottom: 1px solid rgba(255,255,255,.06);
}
.nav { display: flex; align-items: center; justify-content: space-between; padding: 12px 0; }
.branding { display: inline-flex; align-items: center; gap: 10px; text-decoration: none; color: var(--text); }
.logo { width: 34px; height: 34px; border-radius: 8px; box-shadow: 0 0 20px rgba(34,211,238,.35); }
.brand-text { font-weight: 700; letter-spacing: .3px; font-size: 18px; }
.brand-dot { color: var(--accent-500); }

.nav-links { display: flex; align-items: center; gap: 16px; }
.nav-links a { color: var(--text); text-decoration: none; opacity: .9; }
.nav-links a:hover { opacity: 1; }
.btn { border-radius: 12px; padding: 10px 14px; display: inline-flex; align-items: center; gap: 8px; text-decoration: none; }
.btn--primary { color: #fff; background: linear-gradient(90deg, var(--primary-500), var(--accent-500)); border: 0; }
.btn--primary:hover { filter: brightness(1.05); }
.btn--ghost { border: 1px solid rgba(255,255,255,.2); color: var(--text); background: transparent; }
.icon-btn { border: 1px solid rgba(255,255,255,.15); background: transparent; color: var(--text); border-radius: 12px; width: 42px; height: 42px; display: grid; place-items: center; }
.icon-theme { width: 20px; height: 20px; position: relative; display: inline-block; }
.icon-theme::before, .icon-theme::after {
    content: ""; position: absolute; inset: 0; border-radius: 50%;
    box-shadow: inset 10px -10px 0 0 var(--text);
    transform: rotate(45deg);
}

.hamburger { display: none; background: transparent; border: 0; width: 44px; height: 44px; border-radius: 10px; }
.hamburger span { display: block; height: 2px; background: var(--text); margin: 6px 8px; transition: .2s; opacity: .9; }
@media (max-width: 880px) { .hamburger { display: inline-block; } .nav-links a, .btn.btn--ghost { display: none; } .icon-btn { display: none; } }

.mobile-menu {
    position: absolute; inset: auto 0 0 0; transform: translateY(0);
    background: var(--bg-2); border-bottom: 1px solid rgba(255,255,255,.08);
    display: grid; gap: 12px; padding: 14px 4%; box-shadow: var(--shadow);
}
.mobile-menu a { padding: 12px 10px; border-radius: 10px; text-decoration: none; color: var(--text); background: var(--surface); }

/* -------- Hero -------- */
.hero { display: grid; grid-template-columns: 1.1fr .9fr; align-items: center; gap: 24px; padding: 80px 0 40px; }
.hero__content h1 { margin: 0 0 10px; }
.accent { background: linear-gradient(90deg, var(--accent-500), var(--primary-500));
    -webkit-background-clip: text; background-clip: text; color: transparent; }
    .sub { font-weight: 500; opacity: .9; }
    .lead { color: var(--text); opacity: .92; }
    .hero__cta { display: flex; gap: 14px; margin-top: 16px; }

    .hero__visual { display: grid; place-items: center; }
    .circuit { width: min(520px, 90%); filter: drop-shadow(0 18px 30px rgba(14,165,233,.18)); }
    @media (max-width: 980px) { .hero { grid-template-columns: 1fr; } .hero__visual { order: -1; }}

    /* -------- Focus -------- */
    .focus { text-align: left; }
    .focus__icon { width: 46px; height: 46px; display: grid; place-items: center; border-radius: 12px;
        background: radial-gradient(120% 120% at 30% 10%, rgba(14,165,233,.28), rgba(14,165,233,.12));
        color: var(--text); margin-bottom: 10px; }

        /* -------- Stack -------- */
        .stack-cloud h3 { margin-top: 0; }
        .tags span { background: rgba(34,211,238,.12); border: 1px solid rgba(34,211,238,.25); }

        /* -------- Forms -------- */
        .form-row { display: grid; gap: 6px; margin-bottom: 12px; }
        label { font-weight: 600; }
        input, textarea {
            width: 100%; padding: 12px 14px; color: var(--text); background: var(--surface);
            border: 1px solid rgba(255,255,255,.16); border-radius: 12px; outline: none;
        }
        input:focus, textarea:focus { border-color: var(--primary-500); box-shadow: 0 0 0 3px rgba(14,165,233,.18); }
        .form-actions { display: flex; align-items: center; gap: 12px; }
        .form-hint { margin: 0; color: var(--muted); }

        /* -------- Footer -------- */
        .site-footer { border-top: 1px solid rgba(255,255,255,.08); margin-top: 40px; padding: 36px 0; background: rgba(0,0,0,.15); }
        .footer-grid { display: grid; align-items: center; gap: 10px; grid-template-columns: auto 1fr; }
        .footer-brand { display: inline-flex; align-items: center; gap: 10px; }
        .footer-links { display: flex; flex-wrap: wrap; gap: 14px; justify-content: flex-end; }
        .footnote { grid-column: 1 / -1; color: var(--muted); margin: 4px 0 0; font-size: 14px; }

        /* -------- Scroll reveal -------- */
        .reveal { opacity: 0; transform: translateY(12px); }
        .reveal.in { opacity: 1; transform: none; transition: opacity .6s ease, transform .6s ease; }