:root {
  --ink: #22262b;
  --paper: #fffaf3;
  --card: #ffffff;
  --accent: #1f6f5c;
  --accent-dark: #164f41;
  --accent-ink: #ffffff;
  --border: #e2d9c8;
  --muted: #5b6169;
  --tip-bg: #fff3d6;
  --tip-border: #e8c874;
  --danger-bg: #fdeceb;
  --danger-border: #e7a79e;
  --success-bg: #eaf6ee;
  --success-border: #9fd3ae;
  --focus: #0b5fff;
  --shadow-sm: 0 1px 2px rgba(34, 38, 43, 0.06);
  --shadow-card: 0 8px 24px rgba(34, 38, 43, 0.08);
  --shadow-btn: 0 2px 0 rgba(0, 0, 0, 0.12);
}

* {
  box-sizing: border-box;
}

html, body {
  margin: 0;
  padding: 0;
}

body {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  background:
    radial-gradient(720px 360px at 50% -80px, #f3ecd9 0%, rgba(243, 236, 217, 0) 70%),
    var(--paper);
  color: var(--ink);
  font-family: -apple-system, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  font-size: 20px;
  line-height: 1.5;
  letter-spacing: 0.1px;
}

button {
  font-family: inherit;
}

a {
  color: var(--accent);
}

.app-header {
  padding: 18px 24px;
  border-bottom: 1px solid var(--border);
  background: var(--card);
  box-shadow: var(--shadow-sm);
  position: relative;
  z-index: 1;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
}

.brand-mark {
  display: block;
  flex-shrink: 0;
}

.logo {
  font-size: 21px;
  font-weight: 800;
  color: var(--ink);
  letter-spacing: -0.2px;
}

.install-banner {
  max-width: 620px;
  margin: 20px auto 0;
  padding: 16px 20px;
  background: var(--tip-bg);
  border: 1px solid var(--tip-border);
  border-radius: 12px;
  font-size: 17px;
  box-shadow: var(--shadow-sm);
}

.install-actions {
  display: flex;
  gap: 10px;
  margin-top: 12px;
  flex-wrap: wrap;
}

.install-actions .option-btn {
  width: auto;
  flex: 1 1 auto;
}

.stage {
  flex: 1;
  width: 100%;
  max-width: 620px;
  margin: 0 auto;
  padding: 32px 20px 48px;
}

.loading {
  color: var(--muted);
}

.card {
  background: var(--card);
  border: 1px solid var(--border);
  border-left: 5px solid var(--accent);
  border-radius: 16px;
  padding: 30px 26px;
  box-shadow: var(--shadow-card);
  animation: card-in 0.22s ease-out;
}

@keyframes card-in {
  from {
    opacity: 0;
    transform: translateY(6px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.card.escalate {
  background: var(--danger-bg);
  border-color: var(--danger-border);
  border-left-color: #c9564a;
}

.card.success {
  background: var(--success-bg);
  border-color: var(--success-border);
  border-left-color: #4f9d64;
}

.device-picker {
  display: grid;
  gap: 16px;
  margin-top: 24px;
}

.node-text {
  font-size: 24px;
  font-weight: 600;
  line-height: 1.4;
  margin: 0 0 8px;
}

.node-tip {
  margin: 18px 0;
  padding: 14px 16px;
  background: var(--tip-bg);
  border: 1px solid var(--tip-border);
  border-radius: 12px;
  font-size: 18px;
}

.node-tip::before {
  content: "Tip: ";
  font-weight: 700;
}

.options {
  display: grid;
  gap: 14px;
  margin-top: 28px;
}

.option-btn {
  display: block;
  width: 100%;
  padding: 18px 20px;
  font-size: 20px;
  font-weight: 700;
  text-align: left;
  color: var(--accent-ink);
  background: var(--accent);
  border: none;
  border-radius: 12px;
  cursor: pointer;
  box-shadow: var(--shadow-btn);
  transition: transform 0.08s ease, box-shadow 0.08s ease, filter 0.15s ease;
}

.option-btn:hover {
  filter: brightness(1.08);
}

.option-btn:active {
  transform: translateY(2px);
  box-shadow: 0 0 0 rgba(0, 0, 0, 0.12);
}

.option-btn:focus-visible,
.help-btn:focus-visible {
  outline: 3px solid var(--focus);
  outline-offset: 2px;
}

.option-btn.secondary {
  color: var(--ink);
  background: var(--card);
  border: 2px solid var(--accent);
  box-shadow: var(--shadow-sm);
}

.progress {
  margin: 0 0 18px;
  font-size: 16px;
  color: var(--muted);
}

.start-over {
  display: inline-block;
  margin-top: 28px;
  font-size: 18px;
}

.help-bar {
  position: sticky;
  bottom: 0;
  background: var(--card);
  border-top: 1px solid var(--border);
  padding: 14px 20px;
  text-align: center;
  box-shadow: 0 -6px 16px rgba(34, 38, 43, 0.05);
}

.help-label {
  display: block;
  font-size: 15px;
  color: var(--muted);
  margin-bottom: 8px;
}

.help-actions {
  display: flex;
  gap: 12px;
  justify-content: center;
  flex-wrap: wrap;
}

.help-btn {
  padding: 10px 16px;
  font-size: 16px;
  font-weight: 600;
  color: var(--ink);
  background: var(--paper);
  border: 2px solid var(--border);
  border-radius: 10px;
  cursor: pointer;
}

.help-note {
  max-width: 480px;
  margin: 12px auto 0;
  font-size: 15px;
  color: var(--muted);
}

@media (max-width: 420px) {
  body {
    font-size: 18px;
  }
  .node-text {
    font-size: 21px;
  }
}