/* ============================================================
   Calculator Engine — Shared Responsive Stylesheet
   ============================================================ */

:root {
  --ce-primary:    #1a73e8;
  --ce-primary-dk: #1557b0;
  --ce-success:    #2e7d32;
  --ce-bg:         #f8faff;
  --ce-card:       #ffffff;
  --ce-border:     #dde3f0;
  --ce-text:       #212a3e;
  --ce-muted:      #6b7280;
  --ce-radius:     10px;
  --ce-shadow:     0 2px 12px rgba(26,115,232,.10);
  --ce-font:       'Segoe UI', system-ui, -apple-system, sans-serif;
}

/* ── Wrapper ── */
.ce-wrap {
  font-family: var(--ce-font);
  color: var(--ce-text);
  max-width: 780px;
  margin: 0 auto 2rem;
}

/* ── Card ── */
.ce-card {
  background: var(--ce-card);
  border: 1px solid var(--ce-border);
  border-radius: var(--ce-radius);
  box-shadow: var(--ce-shadow);
  padding: 1.75rem;
  margin-bottom: 1.5rem;
}

.ce-card-title {
  font-size: 1.25rem;
  font-weight: 700;
  margin: 0 0 1.25rem;
  color: var(--ce-primary);
  display: flex;
  align-items: center;
  gap: .5rem;
}

/* ── Form ── */
.ce-form-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1rem;
}
@media (max-width: 560px) {
  .ce-form-grid { grid-template-columns: 1fr; }
}

.ce-field {
  display: flex;
  flex-direction: column;
  gap: .35rem;
}
.ce-field.ce-full { grid-column: 1 / -1; }

.ce-field label {
  font-size: .85rem;
  font-weight: 600;
  color: var(--ce-muted);
  text-transform: uppercase;
  letter-spacing: .04em;
}

.ce-field input,
.ce-field select {
  border: 1.5px solid var(--ce-border);
  border-radius: 7px;
  padding: .6rem .85rem;
  font-size: 1rem;
  font-family: var(--ce-font);
  color: var(--ce-text);
  background: var(--ce-bg);
  transition: border-color .2s, box-shadow .2s;
  width: 100%;
  box-sizing: border-box;
}
.ce-field input:focus,
.ce-field select:focus {
  outline: none;
  border-color: var(--ce-primary);
  box-shadow: 0 0 0 3px rgba(26,115,232,.15);
  background: #fff;
}

/* ── Buttons ── */
.ce-btn-row {
  display: flex;
  gap: .75rem;
  flex-wrap: wrap;
  margin-top: 1.25rem;
}

.ce-btn {
  display: inline-flex;
  align-items: center;
  gap: .4rem;
  padding: .65rem 1.4rem;
  border: none;
  border-radius: 7px;
  font-size: .95rem;
  font-weight: 600;
  cursor: pointer;
  transition: background .2s, transform .1s;
  font-family: var(--ce-font);
}
.ce-btn:active { transform: scale(.97); }

.ce-btn-primary { background: var(--ce-primary); color: #fff; }
.ce-btn-primary:hover { background: var(--ce-primary-dk); }

.ce-btn-copy { background: #e8f0fe; color: var(--ce-primary); }
.ce-btn-copy:hover { background: #d2e3fc; }

.ce-btn-reset { background: #f1f3f4; color: var(--ce-text); }
.ce-btn-reset:hover { background: #e2e6ea; }

/* ── Result Box ── */
.ce-result {
  display: none;
  background: linear-gradient(135deg, #e8f0fe 0%, #f0f7ff 100%);
  border: 1.5px solid var(--ce-primary);
  border-radius: var(--ce-radius);
  padding: 1.25rem 1.5rem;
  margin-top: 1.25rem;
}
.ce-result.ce-visible { display: block; }

.ce-result-label {
  font-size: .82rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: .06em;
  color: var(--ce-primary);
  margin-bottom: .4rem;
}

.ce-result-value {
  font-size: 2rem;
  font-weight: 800;
  color: var(--ce-success);
  margin-bottom: .5rem;
  word-break: break-all;
}

.ce-result-breakdown {
  font-size: .88rem;
  color: var(--ce-muted);
  line-height: 1.7;
}

/* ── Formula Box ── */
.ce-formula-box {
  background: #f8f9fa;
  border-left: 4px solid var(--ce-primary);
  border-radius: 0 var(--ce-radius) var(--ce-radius) 0;
  padding: 1rem 1.25rem;
  margin: 1.25rem 0;
}
.ce-formula-title {
  font-size: 1rem;
  font-weight: 700;
  margin: 0 0 .75rem;
  color: var(--ce-text);
}
.ce-formula-row {
  margin-bottom: .4rem;
  font-size: .9rem;
}
.ce-formula-label {
  font-weight: 600;
  color: var(--ce-muted);
}
.ce-formula-code {
  background: #e8eaed;
  border-radius: 4px;
  padding: .15rem .5rem;
  font-family: 'Courier New', monospace;
  font-size: .85rem;
  color: var(--ce-primary-dk);
}

/* ── FAQ ── */
.ce-faq { margin: 2rem 0; }
.ce-faq-title {
  font-size: 1.2rem;
  font-weight: 700;
  margin-bottom: 1rem;
  color: var(--ce-text);
}
.ce-faq-item {
  border: 1px solid var(--ce-border);
  border-radius: var(--ce-radius);
  margin-bottom: .75rem;
  overflow: hidden;
}
.ce-faq-q {
  background: var(--ce-bg);
  margin: 0;
  padding: .9rem 1.1rem;
  font-size: .95rem;
  font-weight: 600;
  cursor: pointer;
  border-bottom: 1px solid var(--ce-border);
}
.ce-faq-a {
  padding: .9rem 1.1rem;
  font-size: .9rem;
  line-height: 1.7;
  color: var(--ce-muted);
}

/* ── Copy feedback ── */
.ce-copied-msg {
  font-size: .8rem;
  color: var(--ce-success);
  font-weight: 600;
  display: none;
  align-items: center;
  gap: .3rem;
}
.ce-copied-msg.ce-show { display: inline-flex; }

/* ── Error ── */
.ce-error {
  background: #fdecea;
  border: 1px solid #f5c6cb;
  color: #c62828;
  border-radius: 7px;
  padding: .7rem 1rem;
  font-size: .88rem;
  margin-top: .75rem;
  display: none;
}
.ce-error.ce-visible { display: block; }