:root {
  --surface: #faf9f7;
  --surface-raised: #ffffff;
  --ink: #1c1b19;
  --ink-soft: #6d675f;
  --hairline: #e4e0d9;
  --accent: #a35b2e;
  --accent-ink: #7d431f;
  --error: #b3372c;

  --text-base: clamp(0.95rem, 0.9rem + 0.2vw, 1.05rem);
  --space-unit: clamp(1rem, 0.8rem + 1vw, 1.75rem);
  --duration: 180ms;
  --ease: cubic-bezier(0.16, 1, 0.3, 1);
}

* { box-sizing: border-box; }

body {
  margin: 0;
  background: var(--surface);
  color: var(--ink);
  font-family: "Futura", "Jost", "Avenir Next", "Hiragino Kaku Gothic ProN", "Noto Sans JP", sans-serif;
  font-size: var(--text-base);
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
}

.hidden { display: none !important; }

/* ---- header ---- */
.site-header {
  display: flex;
  align-items: baseline;
  gap: 1.25rem;
  padding: calc(var(--space-unit) * 1.2) calc(var(--space-unit) * 1.5) var(--space-unit);
  border-bottom: 1px solid var(--hairline);
}
.wordmark {
  font-size: 1.45rem;
  font-weight: 700;
  letter-spacing: 0.22em;
}
.wordmark span {
  font-weight: 300;
  color: var(--accent);
}
.tagline {
  margin: 0;
  color: var(--ink-soft);
  font-size: 0.82rem;
  letter-spacing: 0.08em;
}

/* ---- gate ---- */
.gate {
  min-height: 70vh;
  display: grid;
  place-items: center;
  padding: var(--space-unit);
}
.gate-card {
  width: min(24rem, 100%);
  background: var(--surface-raised);
  border: 1px solid var(--hairline);
  padding: calc(var(--space-unit) * 1.6);
}
.gate-card h1 {
  margin: 0 0 0.25rem;
  font-size: 1.15rem;
  letter-spacing: 0.12em;
}
.gate-note {
  margin: 0 0 1.5rem;
  color: var(--ink-soft);
  font-size: 0.85rem;
}
.gate-card form { display: grid; gap: 0.75rem; }
.gate-card input {
  padding: 0.7rem 0.9rem;
  border: 1px solid var(--hairline);
  background: var(--surface);
  font-size: 1rem;
  letter-spacing: 0.2em;
}
.gate-card input:focus {
  outline: 2px solid var(--accent);
  outline-offset: -1px;
}

/* ---- buttons ---- */
.btn {
  padding: 0.75rem 1.4rem;
  border: 1px solid var(--ink);
  background: transparent;
  color: var(--ink);
  font: inherit;
  letter-spacing: 0.14em;
  cursor: pointer;
  transition: background var(--duration) var(--ease), color var(--duration) var(--ease),
              border-color var(--duration) var(--ease), transform var(--duration) var(--ease);
}
.btn.primary {
  background: var(--ink);
  color: var(--surface-raised);
}
.btn.primary:hover:not(:disabled) {
  background: var(--accent-ink);
  border-color: var(--accent-ink);
}
.btn:active:not(:disabled) { transform: translateY(1px); }
.btn:disabled { opacity: 0.35; cursor: not-allowed; }
.btn:focus-visible { outline: 2px solid var(--accent); outline-offset: 2px; }

/* ---- studio layout ---- */
.studio {
  display: grid;
  grid-template-columns: minmax(19rem, 24rem) 1fr;
  gap: calc(var(--space-unit) * 1.5);
  padding: calc(var(--space-unit) * 1.5);
  max-width: 82rem;
  margin: 0 auto;
}
@media (max-width: 60rem) {
  .studio { grid-template-columns: 1fr; }
}

.panel { min-width: 0; }

.step {
  font-size: 0.85rem;
  letter-spacing: 0.18em;
  margin: 0 0 0.75rem;
  font-weight: 600;
}
.step em {
  font-style: normal;
  color: var(--accent);
  margin-right: 0.5rem;
  font-weight: 700;
}
.step:not(:first-child) { margin-top: 2rem; }

/* ---- upload ---- */
.drop {
  display: block;
  border: 1.5px dashed var(--hairline);
  background: var(--surface-raised);
  min-height: 13rem;
  display: grid;
  place-items: center;
  text-align: center;
  padding: 1rem;
  cursor: pointer;
  transition: border-color var(--duration) var(--ease), background var(--duration) var(--ease);
}
.drop:hover, .drop.dragover {
  border-color: var(--accent);
  background: #fff;
}
.drop-main { margin: 0 0 0.3rem; font-weight: 600; }
.drop-sub { margin: 0; color: var(--ink-soft); font-size: 0.78rem; }
#preview {
  max-width: 100%;
  max-height: 22rem;
  display: block;
}

/* ---- model row ---- */
.model-row { display: grid; gap: 0.75rem; }
#model {
  padding: 0.6rem 0.8rem;
  border: 1px solid var(--hairline);
  background: var(--surface-raised);
  font: inherit;
}
.compare-toggle {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-size: 0.85rem;
  color: var(--ink-soft);
  cursor: pointer;
}
.compare-toggle input { accent-color: var(--accent); }

.generate {
  width: 100%;
  margin-top: 2rem;
  font-size: 1rem;
  padding: 0.9rem;
}

/* ---- result ---- */
.result-panel {
  background: var(--surface-raised);
  border: 1px solid var(--hairline);
  padding: var(--space-unit);
  min-height: 32rem;
}
.result-empty {
  height: 100%;
  min-height: 28rem;
  display: grid;
  place-items: center;
  color: var(--ink-soft);
  font-size: 0.9rem;
}

.loading {
  min-height: 28rem;
  display: grid;
  place-content: center;
  justify-items: center;
  gap: 0.75rem;
  text-align: center;
}
.spinner {
  width: 2.4rem;
  height: 2.4rem;
  border: 2px solid var(--hairline);
  border-top-color: var(--accent);
  border-radius: 50%;
  animation: spin 0.9s linear infinite;
}
@keyframes spin { to { transform: rotate(360deg); } }
@media (prefers-reduced-motion: reduce) {
  .spinner { animation-duration: 2.5s; }
}
.loading-sub { color: var(--ink-soft); font-size: 0.8rem; margin: 0; }

.result-card + .result-card {
  margin-top: 2rem;
  padding-top: 2rem;
  border-top: 1px solid var(--hairline);
}
.result-head {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.6rem 1rem;
  margin-bottom: 0.75rem;
}
.model-chip {
  font-size: 0.72rem;
  letter-spacing: 0.1em;
  border: 1px solid var(--hairline);
  padding: 0.15rem 0.6rem;
  color: var(--ink-soft);
}
.result-actions { margin-left: auto; display: flex; gap: 0.5rem; }
.result-svg { border: 1px solid var(--hairline); }
.result-svg svg { display: block; width: 100%; height: auto; }

.fixes {
  margin-top: 0.75rem;
  font-size: 0.8rem;
  color: var(--ink-soft);
}
.fixes summary { cursor: pointer; letter-spacing: 0.08em; }
.fixes ul { margin: 0.4rem 0 0; padding-left: 1.2rem; }

.usage {
  margin-top: 0.4rem;
  font-size: 0.72rem;
  color: var(--ink-soft);
  letter-spacing: 0.05em;
}

.error {
  color: var(--error);
  font-size: 0.85rem;
  margin-top: 0.75rem;
}

.result-error {
  border: 1px solid var(--error);
  padding: 0.9rem 1rem;
  color: var(--error);
  font-size: 0.9rem;
}

/* ---- footer ---- */
.site-footer {
  padding: var(--space-unit) calc(var(--space-unit) * 1.5) calc(var(--space-unit) * 2);
  color: var(--ink-soft);
  font-size: 0.72rem;
  letter-spacing: 0.1em;
  border-top: 1px solid var(--hairline);
  margin-top: calc(var(--space-unit) * 2);
}
.site-footer p { margin: 0; }