:root {
  --ink: #102a2a;
  --muted: #698080;
  --line: #dce8e5;
  --paper: #f5f7f3;
  --card: rgba(255, 255, 255, .88);
  --mint: #caff72;
  --teal: #006f6b;
  --teal-dark: #005a57;
  --orange: #ff7a4d;
  --shadow: 0 24px 60px rgba(20, 60, 56, .09);
}

* { box-sizing: border-box; }

body {
  margin: 0;
  min-width: 320px;
  color: var(--ink);
  background:
    radial-gradient(circle at 8% 0%, rgba(202, 255, 114, .28), transparent 24rem),
    radial-gradient(circle at 96% 45%, rgba(0, 111, 107, .08), transparent 28rem),
    var(--paper);
  font-family: Inter, "Noto Sans JP", "Hiragino Sans", system-ui, sans-serif;
}

body::before {
  content: "";
  position: fixed;
  inset: 0;
  pointer-events: none;
  opacity: .17;
  background-image: linear-gradient(rgba(16, 42, 42, .08) 1px, transparent 1px), linear-gradient(90deg, rgba(16, 42, 42, .08) 1px, transparent 1px);
  background-size: 40px 40px;
  mask-image: linear-gradient(to bottom, black, transparent 58%);
}

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

.app {
  position: relative;
  width: min(1120px, calc(100% - 40px));
  margin: 0 auto;
  padding: 48px 0 32px;
}

.hero { max-width: 720px; margin-bottom: 24px; }
.eyebrow, .label {
  margin: 0 0 12px;
  color: var(--teal);
  font-size: .72rem;
  font-weight: 800;
  letter-spacing: .17em;
}
.pulse {
  display: inline-block;
  width: 8px;
  height: 8px;
  margin-right: 8px;
  border-radius: 50%;
  background: var(--orange);
  box-shadow: 0 0 0 5px rgba(255, 122, 77, .14);
}
.hero h1 {
  margin: 0;
  font-size: clamp(2.4rem, 5vw, 4rem);
  line-height: .88;
  letter-spacing: -.075em;
}
.hero h1 span {
  color: transparent;
  -webkit-text-stroke: 2px var(--ink);
}
.hero > p {
  margin: 28px 0 0;
  color: var(--muted);
  font-size: clamp(1rem, 2vw, 1.2rem);
}

.now-card {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 24px;
  margin-bottom: 20px;
  padding: 28px 32px;
  color: white;
  background: var(--ink);
  border-radius: 20px;
  box-shadow: var(--shadow);
}
.now-card .label { color: var(--mint); }
.now-value-row { display: flex; align-items: center; gap: 10px; }
.now-value {
  font-size: clamp(2rem, 6vw, 4rem);
  font-weight: 700;
  letter-spacing: -.05em;
}
.current-date { margin: 6px 0 0; color: #a9c1bf; }
.icon-button {
  width: 38px;
  height: 38px;
  color: #bcd0ce;
  background: transparent;
  border: 1px solid #496261;
  border-radius: 10px;
  cursor: pointer;
}
.unit-switch {
  display: flex;
  padding: 4px;
  background: rgba(255,255,255,.08);
  border-radius: 12px;
}
.unit-button {
  padding: 9px 14px;
  color: #b8ccca;
  background: transparent;
  border: 0;
  border-radius: 9px;
  cursor: pointer;
}
.unit-button.active { color: var(--ink); background: var(--mint); font-weight: 800; }

.converter-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 20px; }
.card {
  padding: 32px;
  background: var(--card);
  border: 1px solid rgba(16, 42, 42, .08);
  border-radius: 20px;
  box-shadow: var(--shadow);
  backdrop-filter: blur(12px);
}
.card-heading { display: flex; align-items: flex-start; gap: 16px; margin-bottom: 30px; }
.step-number {
  flex: 0 0 auto;
  display: grid;
  place-items: center;
  width: 42px;
  height: 42px;
  color: var(--teal);
  background: #e3f7ec;
  border-radius: 50%;
  font: 800 .78rem ui-monospace, monospace;
}
h2 { margin: 0 0 5px; font-size: 1.3rem; letter-spacing: -.025em; }
.card-heading p { margin: 0; color: var(--muted); font-size: .88rem; }
label { display: block; margin: 18px 0 8px; font-size: .8rem; font-weight: 800; }
input, select {
  width: 100%;
  height: 54px;
  padding: 0 15px;
  color: var(--ink);
  background: #f9fbf8;
  border: 1px solid var(--line);
  border-radius: 11px;
  outline: none;
}
input:focus, select:focus { border-color: var(--teal); box-shadow: 0 0 0 3px rgba(0,111,107,.1); }
.mono, code { font-family: "SFMono-Regular", Consolas, "Liberation Mono", monospace; }
.input-shell { position: relative; }
.input-shell input { padding-right: 72px; }
.unit-badge {
  position: absolute;
  top: 50%;
  right: 10px;
  transform: translateY(-50%);
  padding: 5px 9px;
  color: var(--teal);
  background: #e3f7ec;
  border-radius: 7px;
  font-size: .72rem;
  font-weight: 800;
}
.hint { margin: 8px 0 0; color: var(--muted); font-size: .74rem; }
.error { min-height: 18px; margin: 6px 0 0; color: #c4492c; font-size: .78rem; }
.primary-button {
  display: flex;
  justify-content: space-between;
  width: 100%;
  margin-top: 18px;
  padding: 15px 18px;
  color: white;
  background: var(--teal);
  border: 0;
  border-radius: 11px;
  font-weight: 800;
  cursor: pointer;
  transition: transform .15s, background .15s;
}
.primary-button:hover { background: var(--teal-dark); transform: translateY(-1px); }
.text-button {
  margin: 10px 0 0;
  padding: 4px 0;
  color: var(--teal);
  background: transparent;
  border: 0;
  font-size: .78rem;
  font-weight: 800;
  cursor: pointer;
}
.result {
  display: grid;
  min-height: 142px;
  margin-top: 18px;
  padding: 20px;
  background: #f2f5f1;
  border: 1px dashed #cbdad6;
  border-radius: 13px;
}
.result-placeholder { place-self: center; text-align: center; color: #93a5a3; font-size: .8rem; }
.result-icon { display: block; margin-bottom: 6px; font-size: 1.6rem; }
.result-content { align-self: center; }
.result-label { margin: 0 0 7px; color: var(--muted); font-size: .72rem; font-weight: 800; }
.result-main { display: flex; align-items: center; justify-content: space-between; gap: 8px; }
.result-main strong { font-size: clamp(1rem, 2vw, 1.25rem); word-break: break-all; }
.result-sub { margin: 9px 0 0; color: var(--muted); font-size: .76rem; }
.result-pair + .result-pair { margin-top: 16px; padding-top: 16px; border-top: 1px solid var(--line); }

.guide { margin-top: 20px; padding: 28px 32px; background: #e8efe8; border-radius: 20px; }
.guide-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 16px; }
.guide-grid div { display: grid; gap: 4px; }
.guide-grid strong { font-size: 1.3rem; }
.guide-grid span { color: var(--muted); font-size: .78rem; }
.guide-grid code { color: var(--teal); font-size: .78rem; }
footer { padding: 26px 0 0; color: var(--muted); text-align: center; font-size: .74rem; }
.toast {
  position: fixed;
  left: 50%;
  bottom: 24px;
  z-index: 10;
  transform: translate(-50%, 20px);
  padding: 11px 18px;
  color: white;
  background: var(--ink);
  border-radius: 10px;
  opacity: 0;
  pointer-events: none;
  transition: .2s ease;
}
.toast.show { transform: translate(-50%, 0); opacity: 1; }

.ad-unit {
  width: 100%;
  margin: 16px 0;
  overflow: hidden;
}

@media (max-width: 760px) {
  .app { width: min(100% - 24px, 620px); padding-top: 28px; }
  .hero h1 { font-size: clamp(2.8rem, 14vw, 4.6rem); }
  .now-card { align-items: flex-start; padding: 24px; }
  .now-value { font-size: clamp(1.7rem, 8.5vw, 3rem); }
  .converter-grid { grid-template-columns: 1fr; }
  .card { padding: 24px; }
  .guide-grid { grid-template-columns: 1fr; gap: 20px; }
}

@media (max-width: 470px) {
  .now-card { flex-direction: column; }
  .unit-switch { align-self: stretch; }
  .unit-button { flex: 1; }
}

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