:root {
  --ink: #14201b;
  --paper: #eef3ee;
  --moss: #2f6b4f;
  --haze: #9bb8a8;
  --glow: #d7f0e2;
}

* {
  box-sizing: border-box;
}

html,
body {
  margin: 0;
  min-height: 100%;
}

body {
  color: var(--ink);
  font-family: "IBM Plex Sans JP", sans-serif;
  background:
    radial-gradient(1200px 600px at 10% -10%, var(--glow), transparent 60%),
    radial-gradient(900px 500px at 110% 20%, #cfe0d6, transparent 55%),
    linear-gradient(160deg, #f7fbf8 0%, var(--paper) 45%, #e3ebe5 100%);
}

.stage {
  min-height: 100vh;
  display: grid;
  align-content: center;
  gap: 0.75rem;
  padding: 2.5rem clamp(1.25rem, 4vw, 4rem);
  max-width: 42rem;
}

.brand {
  margin: 0;
  font-family: Syne, sans-serif;
  font-size: clamp(2rem, 6vw, 3.25rem);
  letter-spacing: -0.03em;
  color: var(--moss);
  animation: rise 700ms ease both;
}

h1 {
  margin: 0;
  font-size: clamp(1.4rem, 3.5vw, 2rem);
  font-weight: 600;
  line-height: 1.25;
  animation: rise 700ms ease 80ms both;
}

.sub {
  margin: 0;
  color: #405349;
  animation: rise 700ms ease 140ms both;
}

.payload {
  margin: 1rem 0 0;
  padding: 1rem 1.1rem;
  overflow: auto;
  border-left: 3px solid var(--haze);
  background: rgba(255, 255, 255, 0.55);
  font-size: 0.85rem;
  line-height: 1.45;
  animation: rise 700ms ease 200ms both;
}

.stage.is-error .brand {
  color: #8a3b2d;
}

@keyframes rise {
  from {
    opacity: 0;
    transform: translateY(10px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}