:root {
  color-scheme: dark;
  --bg: #07101d;
  --card: rgba(17, 30, 48, 0.86);
  --card-border: rgba(129, 163, 197, 0.16);
  --text: #edf6ff;
  --muted: #92a8bd;
  --accent: #37d6b0;
  --accent-bright: #55f0ca;
  --blue: #65a9ff;
  --danger: #ffbc70;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  min-height: 100vh;
  font-family: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  color: var(--text);
  background:
    radial-gradient(circle at 20% -10%, rgba(44, 132, 180, .28), transparent 36rem),
    radial-gradient(circle at 110% 45%, rgba(27, 170, 133, .14), transparent 30rem),
    var(--bg);
}

body::before {
  content: "";
  position: fixed;
  inset: 0;
  pointer-events: none;
  opacity: .18;
  background-image: linear-gradient(rgba(255,255,255,.025) 1px, transparent 1px), linear-gradient(90deg, rgba(255,255,255,.025) 1px, transparent 1px);
  background-size: 32px 32px;
}

.shell { position: relative; width: min(760px, calc(100% - 32px)); margin: 0 auto; padding: 70px 0 36px; }
.language-switcher { position: absolute; top: 24px; right: 0; display: flex; gap: 4px; padding: 4px; border: 1px solid var(--card-border); border-radius: 10px; background: rgba(10, 23, 37, .72); }
.language-button { min-width: 38px; height: 30px; padding: 0 9px; border: 0; border-radius: 7px; color: var(--muted); background: transparent; font: 800 .73rem Inter, system-ui, sans-serif; letter-spacing: .06em; cursor: pointer; }
.language-button:hover { color: var(--text); }
.language-button.active { color: #07151e; background: var(--accent); }
.language-button:focus-visible { outline: 2px solid var(--accent-bright); outline-offset: 2px; }
.hero { display: flex; align-items: center; gap: 22px; margin-bottom: 38px; }
.brand { display: grid; place-items: center; flex: 0 0 68px; width: 68px; height: 68px; border-radius: 20px; background: linear-gradient(145deg, #1bdec0, #238dd3); box-shadow: 0 16px 40px rgba(24, 182, 174, .22); }
.brand svg { width: 43px; fill: none; stroke: #06131f; stroke-width: 3.3; stroke-linecap: round; stroke-linejoin: round; }
.eyebrow { margin: 0 0 5px; color: var(--accent); font-size: .73rem; font-weight: 800; letter-spacing: .18em; text-transform: uppercase; }
h1 { margin: 0; font-size: clamp(2rem, 6vw, 3.25rem); line-height: 1.05; letter-spacing: -.045em; }
.intro { margin: 11px 0 0; color: var(--muted); font-size: 1rem; line-height: 1.55; }

.card { margin-top: 18px; padding: 30px; border: 1px solid var(--card-border); border-radius: 22px; background: var(--card); box-shadow: 0 20px 60px rgba(0,0,0,.23); backdrop-filter: blur(12px); }
.section-heading { display: flex; gap: 16px; align-items: flex-start; margin-bottom: 27px; }
.step { display: grid; place-items: center; flex: 0 0 40px; width: 40px; height: 40px; border: 1px solid rgba(55,214,176,.35); border-radius: 12px; color: var(--accent); font-size: .76rem; font-weight: 800; }
h2 { margin: 0; font-size: 1.2rem; }
.section-heading p { margin: 6px 0 0; color: var(--muted); font-size: .88rem; }

.form-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 16px; }
label > span, .meta-label { display: block; margin-bottom: 8px; color: var(--muted); font-size: .74rem; font-weight: 700; letter-spacing: .06em; text-transform: uppercase; }
select { width: 100%; min-height: 48px; padding: 0 42px 0 14px; border: 1px solid #2b4055; border-radius: 11px; color: var(--text); background: #0c1928; font: inherit; outline: none; }
select:focus { border-color: var(--accent); box-shadow: 0 0 0 3px rgba(55,214,176,.12); }
.firmware-meta { display: flex; justify-content: space-between; gap: 20px; margin-top: 24px; padding: 18px 20px; border-radius: 13px; background: rgba(5, 14, 25, .55); }
.firmware-meta strong { display: block; font-size: .94rem; }
.version-block { text-align: right; }
.version { color: var(--accent-bright); }
.spinner { display: inline-block; width: 11px; height: 11px; margin-right: 5px; border: 2px solid rgba(85,240,202,.25); border-top-color: var(--accent); border-radius: 50%; animation: spin .8s linear infinite; }
@keyframes spin { to { transform: rotate(1turn); } }

.installer-host { display: flex; justify-content: center; padding: 8px 0; }
esp-web-install-button button[slot="activate"],
esp-web-install-button::part(activate) { min-width: 260px; min-height: 54px; padding: 0 24px; border: 0; border-radius: 13px; color: #06141c; background: linear-gradient(135deg, var(--accent-bright), #39c9ed); box-shadow: 0 11px 28px rgba(55,214,176,.2); font: 800 1rem Inter, system-ui, sans-serif; cursor: pointer; }
esp-web-install-button button[slot="activate"]:hover { filter: brightness(1.06); transform: translateY(-1px); }
esp-web-install-button button[slot="activate"]:focus-visible { outline: 3px solid rgba(85,240,202,.35); outline-offset: 3px; }
esp-web-install-button::part(unsupported) { color: var(--danger); }
.status { margin: 12px 0 0; color: var(--muted); font-size: .83rem; text-align: center; }
details { margin-top: 24px; padding-top: 20px; border-top: 1px solid var(--card-border); color: var(--muted); font-size: .86rem; }
summary { cursor: pointer; color: #b9cad9; }
li { margin: 8px 0; line-height: 1.4; }
.notice { margin: 0 0 18px; padding: 15px 18px; border: 1px solid rgba(255,188,112,.35); border-radius: 13px; color: #ffd8a9; background: rgba(116,71,22,.22); font-size: .9rem; line-height: 1.5; }
footer { display: flex; justify-content: center; align-items: center; gap: 8px; padding: 24px 10px 0; color: #6f879c; font-size: .76rem; text-align: center; }
.secure-dot { width: 7px; height: 7px; border-radius: 50%; background: var(--accent); box-shadow: 0 0 10px var(--accent); }

@media (max-width: 600px) {
  .shell { width: min(100% - 22px, 760px); padding-top: 76px; }
  .language-switcher { top: 24px; }
  .hero { align-items: flex-start; gap: 15px; }
  .brand { width: 54px; height: 54px; flex-basis: 54px; border-radius: 15px; }
  .brand svg { width: 35px; }
  .card { padding: 22px 18px; border-radius: 17px; }
  .form-grid { grid-template-columns: 1fr; }
  .firmware-meta { flex-direction: column; }
  .version-block { text-align: left; }
}