:root {
  --bg: #f4f7f8;
  --surface: #ffffff;
  --text: #111827;
  --muted: #667085;
  --border: #d7dee6;
  --brand: #0f766e;
  --brand-2: #2563eb;
  --accent: #f97316;
  --grad: linear-gradient(135deg, #0f766e 0%, #2563eb 58%, #f97316 100%);
}

* {
  box-sizing: border-box;
}

body {
  display: grid;
  min-height: 100vh;
  place-items: center;
  margin: 0;
  padding: 32px;
  background:
    linear-gradient(rgba(37, 99, 235, 0.08) 1px, transparent 1px),
    linear-gradient(90deg, rgba(15, 118, 110, 0.08) 1px, transparent 1px),
    linear-gradient(180deg, rgba(244, 247, 248, 0.95), rgba(244, 247, 248, 0.9));
  background-size: 44px 44px, 44px 44px, 100% 100%;
  color: var(--text);
  font-family: "Inter", "Helvetica Neue", "Noto Sans JP", "Hiragino Kaku Gothic ProN", "Yu Gothic", sans-serif;
  line-height: 1.75;
  text-align: center;
}

.card {
  width: min(720px, 100%);
  padding: clamp(28px, 6vw, 52px);
  border: 1px solid var(--border);
  border-radius: 8px;
  background: rgba(255, 255, 255, 0.9);
  box-shadow: 0 24px 70px rgba(17, 24, 39, 0.13);
  position: relative;
  overflow: hidden;
  animation: panelIn 0.65s cubic-bezier(0.22, 1, 0.36, 1) both;
}

.card::before {
  content: "";
  position: absolute;
  inset: 0 0 auto;
  height: 5px;
  background: var(--grad);
}

h1 {
  margin: 0;
  font-size: clamp(2rem, 6vw, 3.6rem);
  font-weight: 900;
  letter-spacing: 0;
  line-height: 1.08;
}

p {
  max-width: 44rem;
  margin: 18px auto 0;
  color: var(--muted);
  font-size: clamp(1rem, 2vw, 1.08rem);
}

br {
  display: none;
}

.button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 48px;
  margin-top: 28px;
  padding: 0.8rem 1.2rem;
  border-radius: 8px;
  background: var(--grad);
  box-shadow: 0 16px 38px rgba(37, 99, 235, 0.2);
  color: #fff;
  font-weight: 800;
  line-height: 1.2;
  text-decoration: none;
  transition: transform 0.18s cubic-bezier(0.22, 1, 0.36, 1), box-shadow 0.28s cubic-bezier(0.22, 1, 0.36, 1);
}

.button::after {
  content: "\2192";
  margin-left: 0.5rem;
  font-weight: 900;
  transition: transform 0.18s cubic-bezier(0.22, 1, 0.36, 1);
}

.button:hover {
  box-shadow: 0 20px 48px rgba(15, 118, 110, 0.2), 0 20px 48px rgba(249, 115, 22, 0.14);
  transform: translateY(-2px);
}

.button:hover::after {
  transform: translateX(3px);
}

.button:focus-visible {
  outline: 3px solid rgba(37, 99, 235, 0.35);
  outline-offset: 3px;
}

@keyframes panelIn {
  from {
    opacity: 0;
    transform: translateY(18px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #0b1118;
    --surface: #111923;
    --text: #eef4f8;
    --muted: #91a1af;
    --border: #263545;
  }

  body {
    background:
      linear-gradient(rgba(96, 165, 250, 0.08) 1px, transparent 1px),
      linear-gradient(90deg, rgba(45, 212, 191, 0.07) 1px, transparent 1px),
      linear-gradient(180deg, rgba(11, 17, 24, 0.97), rgba(11, 17, 24, 0.94));
    background-size: 44px 44px, 44px 44px, 100% 100%;
  }

  .card {
    background: rgba(17, 25, 35, 0.9);
    box-shadow: 0 24px 70px rgba(0, 0, 0, 0.35);
  }
}

@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation: none !important;
    transition: none !important;
  }
}