:root {
  color-scheme: light dark;
  --font-sans: "Inter", ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "SF Pro Text",
    "Helvetica Neue", Arial, "Noto Sans JP", "Hiragino Kaku Gothic ProN", "Hiragino Sans", Meiryo, sans-serif;
  --container: 1120px;
  --container-narrow: 960px;

  --radius-sm: 12px;
  --radius-md: 18px;
  --radius-lg: 26px;

  --accent: #2563eb;
  --accent-2: #22d3ee;
  --accent-3: #a78bfa;
  --gradient: linear-gradient(135deg, var(--accent), var(--accent-2) 45%, var(--accent-3));

  --bg-solid: #eef4ff;
  --bg-top: #f7f9ff;
  --surface: rgba(255, 255, 255, 0.72);
  --surface-2: rgba(255, 255, 255, 0.9);
  --text: #0b1220;
  --muted: rgba(30, 41, 59, 0.75);
  --border: rgba(148, 163, 184, 0.28);
  --ring: 0 0 0 4px rgba(37, 99, 235, 0.18);

  --shadow-sm: 0 1px 0 rgba(15, 23, 42, 0.04), 0 18px 40px rgba(15, 23, 42, 0.1);
  --shadow-md: 0 1px 0 rgba(15, 23, 42, 0.04), 0 26px 70px rgba(15, 23, 42, 0.16);
}

:root[data-theme="light"] {
  color-scheme: light;
}

@media (prefers-color-scheme: dark) {
  :root:not([data-theme]) {
    color-scheme: dark;
    --bg-solid: #060816;
    --bg-top: #0b1022;
    --surface: rgba(10, 14, 26, 0.72);
    --surface-2: rgba(15, 23, 42, 0.8);
    --text: rgba(226, 232, 240, 0.98);
    --muted: rgba(203, 213, 225, 0.72);
    --border: rgba(148, 163, 184, 0.14);
    --ring: 0 0 0 4px rgba(34, 211, 238, 0.16);
    --shadow-sm: 0 0 0 rgba(0, 0, 0, 0);
    --shadow-md: 0 0 0 rgba(0, 0, 0, 0);
  }
}

:root[data-theme="dark"] {
  color-scheme: dark;
  --bg-solid: #060816;
  --bg-top: #0b1022;
  --surface: rgba(10, 14, 26, 0.72);
  --surface-2: rgba(15, 23, 42, 0.8);
  --text: rgba(226, 232, 240, 0.98);
  --muted: rgba(203, 213, 225, 0.72);
  --border: rgba(148, 163, 184, 0.14);
  --ring: 0 0 0 4px rgba(34, 211, 238, 0.16);
  --shadow-sm: 0 0 0 rgba(0, 0, 0, 0);
  --shadow-md: 0 0 0 rgba(0, 0, 0, 0);
}

*,
*::before,
*::after {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  min-height: 100vh;
  font-family: var(--font-sans);
  color: var(--text);
  background:
    radial-gradient(900px 520px at 12% -12%, rgba(34, 211, 238, 0.28), transparent 60%),
    radial-gradient(760px 520px at 85% 0%, rgba(37, 99, 235, 0.32), transparent 62%),
    radial-gradient(760px 480px at 54% 115%, rgba(167, 139, 250, 0.26), transparent 62%),
    linear-gradient(180deg, var(--bg-top), var(--bg-solid));
  background-repeat: no-repeat;
  background-size: 140% 140%, 150% 150%, 145% 145%, 100% 100%;
  background-position: 0% 0%, 0% 0%, 0% 0%, 0 0;
  animation: ambient-drift 28s ease-in-out infinite;
  line-height: 1.65;
  text-rendering: optimizeLegibility;
  -webkit-font-smoothing: antialiased;
}

@keyframes ambient-drift {
  0% {
    background-position: 0% 0%, 0% 0%, 0% 0%, 0 0;
  }

  40% {
    background-position: -6% 10%, 4% -8%, 2% -12%, 0 0;
  }

  70% {
    background-position: 6% -6%, -4% 6%, -3% 8%, 0 0;
  }

  100% {
    background-position: 0% 0%, 0% 0%, 0% 0%, 0 0;
  }
}

body::before {
  content: "";
  position: fixed;
  inset: 0;
  pointer-events: none;
  background-image: linear-gradient(to right, rgba(15, 23, 42, 0.06) 1px, transparent 1px),
    linear-gradient(to bottom, rgba(15, 23, 42, 0.06) 1px, transparent 1px);
  background-size: 84px 84px;
  background-position: 0 0, 0 0;
  opacity: 0.16;
  -webkit-mask-image: radial-gradient(circle at 50% 0%, #000 0%, transparent 70%);
  mask-image: radial-gradient(circle at 50% 0%, #000 0%, transparent 70%);
  animation: grid-drift 120s linear infinite;
}

@keyframes grid-drift {
  from {
    background-position: 0 0, 0 0;
  }

  to {
    background-position: 84px 84px, 84px 84px;
  }
}

:root[data-reveal="ready"] .reveal {
  opacity: 0;
  transform: translateY(14px);
  filter: blur(10px);
  visibility: hidden;
  transition: opacity 0.6s ease, transform 0.6s cubic-bezier(0.2, 0.9, 0.2, 1), filter 0.6s ease;
}

:root[data-reveal="ready"] .reveal.is-visible {
  opacity: 1;
  transform: translateY(0);
  filter: blur(0);
  visibility: visible;
}

.scroll-progress {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 3px;
  z-index: 60;
  pointer-events: none;
}

.scroll-progress__bar {
  width: 100%;
  height: 100%;
  transform-origin: 0 50%;
  transform: scaleX(var(--scroll-progress, 0));
  background: var(--gradient);
  opacity: 0.82;
  box-shadow: 0 10px 30px rgba(37, 99, 235, 0.28);
}

:root[data-theme="dark"] body::before {
  background-image: linear-gradient(to right, rgba(226, 232, 240, 0.08) 1px, transparent 1px),
    linear-gradient(to bottom, rgba(226, 232, 240, 0.08) 1px, transparent 1px);
  opacity: 0.1;
}

a {
  color: inherit;
  text-decoration-color: rgba(37, 99, 235, 0.35);
  text-decoration-color: color-mix(in srgb, var(--accent) 75%, transparent);
  text-underline-offset: 0.14em;
}

a:hover {
  text-decoration-color: rgba(37, 99, 235, 0.45);
  text-decoration-color: color-mix(in srgb, var(--accent) 85%, transparent);
}

button,
input,
select,
textarea {
  font: inherit;
}

::selection {
  background: rgba(34, 211, 238, 0.22);
}

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

.skip-link {
  position: absolute;
  left: 18px;
  top: 14px;
  padding: 10px 14px;
  border-radius: 999px;
  background: var(--surface-2);
  border: 1px solid var(--border);
  box-shadow: var(--shadow-sm);
  transform: translateY(-200%);
  transition: transform 0.18s ease;
  z-index: 50;
}

.skip-link:focus {
  transform: translateY(0);
}

.container {
  width: 100%;
  max-width: var(--container);
  margin: 0 auto;
  padding: 0 24px;
}

.container--narrow {
  max-width: var(--container-narrow);
}

.site-header {
  position: sticky;
  top: 0;
  z-index: 20;
  border-bottom: 1px solid var(--border);
  background: var(--surface);
  background: color-mix(in srgb, var(--surface) 92%, transparent);
  backdrop-filter: blur(18px);
}

.site-nav {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  padding: 16px 0;
}

.brand {
  display: inline-flex;
  align-items: center;
  text-decoration: none;
  color: var(--text);
  color: color-mix(in srgb, var(--text) 92%, var(--accent));
}

.brand svg {
  display: block;
  height: 32px;
}

.nav-actions {
  display: flex;
  align-items: center;
  gap: 14px;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 10px;
}

.nav-links a {
  color: var(--muted);
  text-decoration: none;
  font-weight: 650;
  padding: 10px 14px;
  border-radius: 999px;
  transition: background 0.18s ease, color 0.18s ease, transform 0.18s ease;
}

.nav-links a:hover {
  color: var(--text);
  background: rgba(37, 99, 235, 0.12);
  color: color-mix(in srgb, var(--text) 85%, var(--accent));
  background: color-mix(in srgb, var(--surface-2) 64%, transparent);
}

.nav-links a[aria-current="page"] {
  color: var(--text);
  background: rgba(37, 99, 235, 0.14);
  border: 1px solid var(--border);
  color: color-mix(in srgb, var(--text) 94%, #ffffff);
  background: color-mix(in srgb, var(--surface-2) 82%, transparent);
  border: 1px solid color-mix(in srgb, var(--border) 75%, transparent);
}

.theme-toggle {
  display: inline-grid;
  place-items: center;
  width: 40px;
  height: 40px;
  border-radius: 999px;
  border: 1px solid var(--border);
  background: var(--surface-2);
  background: color-mix(in srgb, var(--surface-2) 72%, transparent);
  color: var(--text);
  cursor: pointer;
  transition: transform 0.18s ease, border-color 0.18s ease, background 0.18s ease;
}

.theme-toggle:hover {
  transform: translateY(-1px);
  border-color: rgba(37, 99, 235, 0.42);
  background: var(--surface-2);
  border-color: color-mix(in srgb, var(--accent) 42%, var(--border));
  background: color-mix(in srgb, var(--surface-2) 84%, transparent);
}

.theme-toggle:focus-visible {
  outline: none;
  box-shadow: var(--ring);
}

.theme-toggle svg {
  width: 18px;
  height: 18px;
  display: none;
}

:root[data-theme-mode="system"] .theme-toggle .icon--system,
:root[data-theme-mode="light"] .theme-toggle .icon--sun,
:root[data-theme-mode="dark"] .theme-toggle .icon--moon {
  display: block;
}

main {
  padding: 36px 0 96px;
}

.hero {
  padding: 72px 0 40px;
  text-align: center;
}

.badge {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  padding: 8px 16px;
  border-radius: 999px;
  background: rgba(37, 99, 235, 0.12);
  border: 1px solid rgba(37, 99, 235, 0.22);
  color: var(--text);
  background: color-mix(in srgb, var(--accent) 12%, transparent);
  border: 1px solid color-mix(in srgb, var(--accent) 22%, var(--border));
  color: color-mix(in srgb, var(--text) 70%, var(--accent));
  font-weight: 650;
  letter-spacing: 0.02em;
}

.badge-dot {
  width: 8px;
  height: 8px;
  border-radius: 999px;
  background: var(--gradient);
  box-shadow: 0 0 0 6px rgba(37, 99, 235, 0.12);
  animation: pulse 2.6s ease-in-out infinite;
}

@keyframes pulse {
  0%,
  100% {
    transform: scale(1);
  }

  50% {
    transform: scale(1.18);
  }
}

.hero h1 {
  margin: 18px 0 16px;
  font-size: clamp(40px, 5.6vw, 68px);
  letter-spacing: -0.035em;
  line-height: 1.08;
}

.hero h1 .gradient-text {
  background: var(--gradient);
  background-size: 200% 200%;
  animation: gradient-shift 10s ease infinite;
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}

.hero-title-sub {
  display: block;
}

@keyframes gradient-shift {
  0% {
    background-position: 0% 50%;
  }

  50% {
    background-position: 100% 50%;
  }

  100% {
    background-position: 0% 50%;
  }
}

.hero p {
  margin: 0 auto;
  max-width: 720px;
  font-size: 18px;
  color: var(--muted);
}

.hero-actions {
  display: flex;
  justify-content: center;
  align-items: center;
  gap: 12px;
  flex-wrap: wrap;
  margin-top: 30px;
}

.button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  padding: 13px 22px;
  border-radius: 999px;
  border: 1px solid var(--border);
  background: var(--surface-2);
  color: var(--text);
  background: color-mix(in srgb, var(--surface-2) 68%, transparent);
  color: color-mix(in srgb, var(--text) 92%, #ffffff);
  text-decoration: none;
  font-weight: 650;
  cursor: pointer;
  box-shadow: var(--shadow-sm);
  transition: transform 0.18s ease, box-shadow 0.18s ease, background 0.18s ease;
}

.button:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-md);
}

.button:focus-visible {
  outline: none;
  box-shadow: var(--shadow-md), var(--ring);
}

.button--primary {
  border-color: transparent;
  background: var(--gradient);
  color: white;
  box-shadow: 0 22px 55px rgba(37, 99, 235, 0.32);
}

.button--primary:hover {
  box-shadow: 0 30px 70px rgba(37, 99, 235, 0.38);
}

.button--ghost {
  background: transparent;
  box-shadow: none;
}

.button--ghost:hover {
  box-shadow: none;
  background: rgba(37, 99, 235, 0.1);
}

.section {
  padding: 46px 0 0;
}

.section-header {
  text-align: center;
  margin-bottom: 26px;
}

.section-title {
  margin: 0 0 10px;
  font-size: 28px;
  letter-spacing: -0.02em;
}

.section-lead {
  margin: 0 auto;
  max-width: 720px;
  color: var(--muted);
}

.card-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: 20px;
}

.card {
  position: relative;
  border-radius: var(--radius-lg);
  border: 1px solid var(--border);
  background: var(--surface-2);
  background: color-mix(in srgb, var(--surface-2) 72%, transparent);
  padding: 24px;
  box-shadow: var(--shadow-sm);
  overflow: hidden;
  text-decoration: none;
  color: inherit;
  transition: transform 0.18s ease, box-shadow 0.18s ease, border-color 0.18s ease;
}

.card::before {
  content: "";
  position: absolute;
  inset: 0;
  background: radial-gradient(
    420px circle at var(--spotlight-x, 50%) var(--spotlight-y, 40%),
    rgba(34, 211, 238, 0.22),
    transparent 60%
  );
  opacity: 0;
  transition: opacity 0.18s ease;
  pointer-events: none;
}

.card[data-spotlight="on"]::before,
.card:focus-visible::before {
  opacity: 1;
}

.card::after {
  content: "";
  position: absolute;
  inset: -120px -120px auto auto;
  width: 260px;
  height: 260px;
  background: radial-gradient(circle, rgba(34, 211, 238, 0.26), transparent 60%);
  transform: rotate(18deg);
  opacity: 0.8;
  pointer-events: none;
}

.card:hover {
  transform: translateY(-3px);
  border-color: rgba(37, 99, 235, 0.45);
  border-color: color-mix(in srgb, var(--accent) 36%, var(--border));
  box-shadow: var(--shadow-md);
}

.card-top {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 14px;
  margin-bottom: 18px;
}

.card-icon {
  width: 46px;
  height: 46px;
  border-radius: 16px;
  border: 1px solid var(--border);
  background: var(--surface);
  border: 1px solid color-mix(in srgb, var(--border) 85%, transparent);
  background: color-mix(in srgb, var(--surface) 72%, transparent);
  display: grid;
  place-items: center;
  box-shadow: 0 0 0 1px rgba(255, 255, 255, 0.08) inset;
}

.card-icon svg {
  width: 22px;
  height: 22px;
}

.pill {
  display: inline-flex;
  align-items: center;
  padding: 6px 10px;
  border-radius: 999px;
  border: 1px solid var(--border);
  border: 1px solid color-mix(in srgb, var(--border) 80%, transparent);
  color: var(--muted);
  font-size: 12px;
  font-weight: 650;
  letter-spacing: 0.03em;
}

.card h3 {
  margin: 0 0 10px;
  font-size: 20px;
  letter-spacing: -0.01em;
  position: relative;
  z-index: 1;
}

.card p {
  margin: 0;
  color: var(--muted);
  position: relative;
  z-index: 1;
}

.card-footer {
  margin-top: 18px;
  font-weight: 650;
  color: var(--accent);
  color: color-mix(in srgb, var(--accent) 88%, var(--text));
  position: relative;
  z-index: 1;
}

.steps {
  list-style: none;
  padding: 0;
  margin: 0 auto;
  max-width: 880px;
  display: grid;
  gap: 14px;
}

.step {
  display: flex;
  gap: 16px;
  align-items: flex-start;
  border-radius: var(--radius-lg);
  border: 1px solid var(--border);
  background: var(--surface-2);
  background: color-mix(in srgb, var(--surface-2) 74%, transparent);
  padding: 18px 20px;
  box-shadow: var(--shadow-sm);
}

.step-number {
  width: 42px;
  height: 42px;
  border-radius: 16px;
  display: grid;
  place-items: center;
  font-weight: 750;
  background: rgba(37, 99, 235, 0.16);
  border: 1px solid rgba(37, 99, 235, 0.28);
  color: var(--text);
  background: color-mix(in srgb, var(--accent) 18%, transparent);
  border: 1px solid color-mix(in srgb, var(--accent) 28%, var(--border));
  color: color-mix(in srgb, var(--text) 78%, var(--accent));
  flex: 0 0 auto;
}

.step strong {
  display: block;
  margin-bottom: 6px;
  letter-spacing: -0.01em;
}

.step p {
  margin: 0;
  color: var(--muted);
}

.page-hero {
  margin-bottom: 28px;
  text-align: left;
}

.page-hero h1 {
  margin: 18px 0 12px;
  font-size: clamp(34px, 4.3vw, 52px);
  letter-spacing: -0.03em;
  line-height: 1.12;
}

.page-hero p {
  margin: 0 0 14px;
  color: var(--muted);
  max-width: 740px;
}

.contact-mail a {
  font-weight: 650;
}

.split {
  display: grid;
  grid-template-columns: minmax(0, 1.25fr) minmax(0, 0.75fr);
  gap: 22px;
  align-items: start;
}

.panel {
  border-radius: var(--radius-lg);
  border: 1px solid var(--border);
  background: var(--surface-2);
  background: color-mix(in srgb, var(--surface-2) 78%, transparent);
  padding: 30px;
  box-shadow: var(--shadow-sm);
}

.panel h2 {
  margin: 0 0 14px;
  font-size: 20px;
  letter-spacing: -0.01em;
}

form {
  display: grid;
  gap: 18px;
}

.input-group {
  display: grid;
  gap: 10px;
}

label {
  font-weight: 650;
}

input,
textarea,
select {
  width: 100%;
  padding: 14px 16px;
  border-radius: 14px;
  border: 1px solid rgba(148, 163, 184, 0.35);
  background: rgba(255, 255, 255, 0.78);
  border: 1px solid color-mix(in srgb, var(--border) 90%, rgba(15, 23, 42, 0.12));
  background: color-mix(in srgb, #ffffff 70%, transparent);
  color: var(--text);
  transition: box-shadow 0.18s ease, border-color 0.18s ease, background 0.18s ease;
}

:root[data-theme="dark"] input,
:root[data-theme="dark"] textarea,
:root[data-theme="dark"] select {
  background: rgba(10, 14, 26, 0.92);
  background: color-mix(in srgb, rgba(10, 14, 26, 0.92) 88%, transparent);
}

input:focus-visible,
textarea:focus-visible,
select:focus-visible {
  outline: none;
  border-color: rgba(37, 99, 235, 0.65);
  border-color: color-mix(in srgb, var(--accent) 52%, var(--border));
  box-shadow: var(--ring);
}

input[aria-invalid="true"],
textarea[aria-invalid="true"],
select[aria-invalid="true"] {
  border-color: rgba(239, 68, 68, 0.72);
  box-shadow: 0 0 0 4px rgba(239, 68, 68, 0.14);
}

textarea {
  min-height: 170px;
  resize: vertical;
}

.hint {
  margin: -6px 0 0;
  color: var(--muted);
  font-size: 14px;
}

.status {
  margin: 0;
  color: var(--muted);
  font-size: 14px;
}

.status[data-state="error"] {
  color: rgba(239, 68, 68, 0.92);
}

.list {
  margin: 0;
  padding-left: 18px;
  color: var(--muted);
  display: grid;
  gap: 8px;
}

.stack {
  display: grid;
  gap: 18px;
}

.prose h2 {
  margin-top: 0;
  margin-bottom: 12px;
  font-size: 22px;
}

.prose p,
.prose li,
.prose dd {
  color: var(--muted);
}

.prose ul {
  margin: 12px 0 0;
  padding-left: 20px;
}

.prose dl {
  margin: 0;
}

.prose dt {
  font-weight: 650;
  margin-top: 14px;
}

.meta {
  display: flex;
  flex-wrap: wrap;
  gap: 14px 18px;
  margin-top: 30px;
  color: var(--muted);
}

.site-footer {
  padding: 34px 0 54px;
  color: var(--muted);
  text-align: center;
}

.footer-links {
  display: inline-flex;
  flex-wrap: wrap;
  gap: 10px 18px;
  justify-content: center;
}

.footer-links a {
  text-decoration: none;
  font-weight: 650;
  color: var(--accent);
  color: color-mix(in srgb, var(--text) 74%, var(--accent));
}

.site-footer small {
  display: block;
  margin-top: 16px;
}

@media (max-width: 860px) {
  .split {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 720px) {
  main {
    padding: 24px 0 82px;
  }

  .site-nav {
    flex-wrap: wrap;
  }

  .nav-actions {
    width: 100%;
    justify-content: space-between;
  }

  .nav-links {
    flex-wrap: wrap;
    justify-content: center;
  }

  .hero {
    padding: 58px 0 30px;
  }

  .panel {
    padding: 24px;
  }
}

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }

  *,
  *::before,
  *::after {
    transition: none !important;
    animation: none !important;
  }
}

.back-to-top {
  position: fixed;
  right: 18px;
  bottom: 18px;
  width: 44px;
  height: 44px;
  border-radius: 999px;
  border: 1px solid var(--border);
  background: var(--surface-2);
  background: color-mix(in srgb, var(--surface-2) 72%, transparent);
  color: var(--text);
  display: grid;
  place-items: center;
  box-shadow: var(--shadow-sm);
  opacity: 0;
  transform: translateY(12px);
  pointer-events: none;
  cursor: pointer;
  transition: opacity 0.2s ease, transform 0.2s ease, border-color 0.2s ease, background 0.2s ease;
  z-index: 50;
}

.back-to-top[data-visible="true"] {
  opacity: 1;
  transform: translateY(0);
  pointer-events: auto;
}

.back-to-top:hover {
  border-color: color-mix(in srgb, var(--accent) 42%, var(--border));
  background: color-mix(in srgb, var(--surface-2) 84%, transparent);
}

.back-to-top:focus-visible {
  outline: none;
  box-shadow: var(--shadow-md), var(--ring);
}

.back-to-top svg {
  width: 18px;
  height: 18px;
}