:root {
  --ink: #0E2238;
  --ink-soft: #44566b;
  --muted: #7b8794;
  --teal: #0e7c86;
  --teal-bright: #20A48A;
  --line: #e4e9ee;
  --bg: #f4f7f8;
  --card: #ffffff;
  --eliminate: #c62828;
  --reduce: #e07000;
  --raise: #1565C0;
  --create: #2e7d32;
  --radius: 14px;
  --shadow: 0 2px 16px rgba(14, 34, 56, 0.07);
}

* { box-sizing: border-box; }

html { -webkit-text-size-adjust: 100%; }

body {
  margin: 0;
  font-family: "Inter", -apple-system, BlinkMacSystemFont, "Segoe UI", Arial, sans-serif;
  color: var(--ink);
  background: var(--bg);
  line-height: 1.55;
}

/* ---- header ---- */
.hdr {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 16px 24px;
  border-bottom: 1px solid var(--line);
  background: #fff;
}
.wordmark {
  font-weight: 800;
  font-size: 20px;
  letter-spacing: -0.02em;
  color: var(--ink);
  text-decoration: none;
}
.wordmark .if { color: var(--teal); }
.lang-toggle { display: inline-flex; gap: 2px; border: 1px solid var(--line); border-radius: 999px; overflow: hidden; }
.lang-toggle button {
  border: 0;
  background: #fff;
  color: var(--muted);
  font: inherit;
  font-size: 13px;
  font-weight: 600;
  padding: 6px 14px;
  cursor: pointer;
}
.lang-toggle button.active { background: var(--teal); color: #fff; }

/* ---- layout ---- */
main { max-width: 1180px; margin: 0 auto; padding: 28px 16px 60px; }

.intro { text-align: center; max-width: 720px; margin: 14px auto 26px; }
.intro h1 { font-size: clamp(1.7rem, 4vw, 2.4rem); margin: 0 0 10px; letter-spacing: -0.02em; }
.intro h1 .thin { font-weight: 300; color: var(--teal); }
.lede { color: var(--ink-soft); font-size: 1.02rem; margin: 0; }

.card {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 22px;
  margin-bottom: 20px;
}

/* ---- composer ---- */
.composer label { display: block; font-weight: 600; margin-bottom: 10px; }
textarea {
  width: 100%;
  resize: vertical;
  min-height: 84px;
  font: inherit;
  color: var(--ink);
  padding: 13px 15px;
  border: 1px solid var(--line);
  border-radius: 10px;
  background: #fcfdfd;
}
textarea:focus { outline: none; border-color: var(--teal-bright); box-shadow: 0 0 0 3px rgba(32,164,138,0.15); }

.examples { display: flex; flex-wrap: wrap; align-items: center; gap: 8px; margin: 14px 0 18px; }
.ex-label { font-size: 13px; color: var(--muted); margin-right: 2px; }
.chip {
  font: inherit; font-size: 13px;
  background: #eef4f4; color: var(--teal);
  border: 1px solid #d7e7e5; border-radius: 999px;
  padding: 6px 12px; cursor: pointer;
}
.chip:hover { background: #e2efee; }

.btn-primary {
  font: inherit; font-weight: 700; font-size: 15px;
  background: var(--teal); color: #fff;
  border: 0; border-radius: 10px;
  padding: 13px 26px; cursor: pointer;
  transition: background .15s ease, transform .05s ease;
}
.btn-primary:hover { background: #0c6a73; }
.btn-primary:active { transform: translateY(1px); }
.btn-primary:disabled { background: #9bb6b3; cursor: default; }

.btn-secondary {
  font: inherit; font-weight: 600; font-size: 14px;
  background: #fff; color: var(--ink);
  border: 1px solid var(--line); border-radius: 10px;
  padding: 10px 18px; cursor: pointer;
}
.btn-secondary:hover { border-color: var(--teal-bright); color: var(--teal); }

/* ---- status / loading ---- */
.status {
  display: flex; align-items: center; gap: 12px;
  justify-content: center;
  color: var(--ink-soft); font-weight: 500;
  padding: 28px;
}
.spinner {
  width: 20px; height: 20px;
  border: 3px solid #d7e2e2;
  border-top-color: var(--teal);
  border-radius: 50%;
  animation: spin 0.8s linear infinite;
}
@keyframes spin { to { transform: rotate(360deg); } }

/* ---- result ---- */
.concept .tag {
  display: inline-block; background: #e7f1ff; color: var(--raise);
  border-radius: 6px; padding: 3px 10px; font-size: 12px; font-weight: 700;
  margin-bottom: 10px;
}
.concept h2 { margin: 0 0 8px; font-size: 1.4rem; letter-spacing: -0.01em; }
.concept p { margin: 0; color: var(--ink-soft); }

.chart canvas { width: 100%; height: auto; display: block; }
.legend { display: flex; flex-wrap: wrap; gap: 18px; margin: 14px 2px 4px; font-size: 13.5px; }
.legend .item { display: inline-flex; align-items: center; gap: 8px; color: var(--ink-soft); }
.legend .swatch { width: 26px; height: 0; border-top: 4px solid; display: inline-block; border-radius: 2px; }
.legend .item.hero { color: var(--ink); font-weight: 600; }
.chart-note { font-size: 12.5px; color: var(--muted); margin: 8px 2px 0; }

/* ---- ERRC grid ---- */
.errc { display: grid; grid-template-columns: repeat(4, 1fr); gap: 14px; background: transparent; border: 0; box-shadow: none; padding: 0; }
.errc-col { background: #fff; border: 1px solid var(--line); border-radius: 12px; overflow: hidden; box-shadow: var(--shadow); }
.errc-col h3 { margin: 0; padding: 11px 14px; color: #fff; font-size: 14px; letter-spacing: .01em; }
.errc-col .en { font-weight: 400; opacity: .85; font-size: 12px; }
.errc-col ul { margin: 0; padding: 12px 14px 16px 30px; font-size: 14px; }
.errc-col li { margin-bottom: 6px; color: var(--ink); }
.errc-eliminate h3 { background: var(--eliminate); }
.errc-reduce h3 { background: var(--reduce); }
.errc-raise h3 { background: var(--raise); }
.errc-create h3 { background: var(--create); }

.actions { display: flex; gap: 12px; margin-top: 22px; }

/* ---- error ---- */
.error { text-align: center; color: var(--eliminate); padding: 22px; font-weight: 500; }

/* ---- footer ---- */
.ftr { text-align: center; color: var(--muted); font-size: 13px; padding: 26px 16px 40px; }

.hidden { display: none !important; }

@media (max-width: 760px) {
  .errc { grid-template-columns: repeat(2, 1fr); }
  .actions { flex-direction: column; }
  .btn-secondary { width: 100%; }
}