/* =============================================================================
   SETTINGS BUTTON & SLIDE-IN PANEL (mirror of help panel, left side)
   ============================================================================= */
.settings-btn {
  width: 32px;
  height: 32px;
  border: 1.5px solid var(--border);
  background: var(--surface);
  color: var(--text2);
  border-radius: 50%;
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 0;
  flex-shrink: 0;
  margin-left: auto;
  position: relative;
  transition: background 0.15s, color 0.15s, border-color 0.15s, transform 0.3s;
}
.settings-btn:hover {
  background: var(--accent-light);
  color: var(--accent);
  border-color: var(--accent);
}
.settings-btn.spin { transform: rotate(90deg); }
.settings-btn svg { width: 16px; height: 16px; }

/* "modified" indicator dot */
.settings-btn .modified-dot {
  position: absolute;
  top: 2px;
  right: 2px;
  width: 7px;
  height: 7px;
  background: var(--warn);
  border-radius: 50%;
  border: 1.5px solid var(--surface);
  display: none;
}
.settings-btn.modified .modified-dot { display: block; }

#settings-backdrop {
  position: fixed;
  inset: 0;
  background: rgba(0,0,0,0.35);
  z-index: 900;
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.25s ease;
}
#settings-backdrop.open {
  opacity: 1;
  pointer-events: auto;
}

#settings-panel {
  position: fixed;
  top: 0;
  left: 0;
  height: 100dvh;
  width: 380px;
  max-width: 90vw;
  background: var(--surface);
  box-shadow: 8px 0 24px rgba(0,0,0,0.12);
  z-index: 1001;
  transform: translateX(-100%);
  transition: transform 0.28s cubic-bezier(0.4, 0, 0.2, 1);
  display: flex;
  flex-direction: column;
  overflow: hidden;
}
#settings-panel.open { transform: translateX(0); }

.settings-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 20px 22px 16px;
  border-bottom: 1px solid var(--border);
  flex-shrink: 0;
}
.settings-header h2 {
  font-size: 16px;
  font-weight: 600;
  color: var(--text);
  margin: 0;
}
.settings-close {
  width: 32px;
  height: 32px;
  border: 1px solid var(--border);
  background: var(--surface);
  color: var(--text2);
  border-radius: var(--radius-sm);
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 20px;
  line-height: 1;
  padding: 0;
  transition: background 0.15s, color 0.15s;
}
.settings-close:hover {
  background: var(--surface2);
  color: var(--text);
}

.settings-body {
  overflow-y: auto;
  padding: 20px 22px 28px;
  flex: 1;
}
.settings-body h3 {
  font-size: 11px;
  text-transform: uppercase;
  letter-spacing: 0.07em;
  font-weight: 600;
  color: var(--accent);
  margin: 0 0 8px;
}
.settings-body > p {
  font-size: 13.5px;
  color: var(--text2);
  line-height: 1.6;
  margin-bottom: 18px;
}

.factor-row { margin-bottom: 18px; }
.factor-label {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 13.5px;
  font-weight: 500;
  color: var(--text);
  margin-bottom: 6px;
}
.factor-label .dot { width: 9px; height: 9px; }

.factor-input-wrap {
  position: relative;
  display: flex;
  align-items: center;
}
.factor-input {
  width: 100%;
  padding: 11px 36px 11px 13px;
  font-size: 15px;
  font-family: var(--mono);
  color: var(--text);
  background: var(--inp-bg);
  border: 1.5px solid var(--inp-border);
  border-radius: var(--radius-sm);
  outline: none;
  transition: border-color 0.18s, box-shadow 0.18s;
  -moz-appearance: textfield;
  appearance: textfield;
}
.factor-input::-webkit-outer-spin-button,
.factor-input::-webkit-inner-spin-button {
  -webkit-appearance: none;
  margin: 0;
}
.factor-input:focus {
  border-color: var(--accent);
  box-shadow: 0 0 0 3px var(--accent-light);
}
.factor-suffix {
  position: absolute;
  right: 12px;
  font-size: 13px;
  color: var(--text2);
  font-family: var(--mono);
  pointer-events: none;
}

.factor-formula {
  font-size: 11px;
  color: var(--text2);
  margin-top: 6px;
  font-family: var(--mono);
  line-height: 1.5;
}

.settings-warning {
  display: none;
  margin-top: 4px;
  padding: 10px 12px;
  background: #fdf4ee;
  border: 1px solid #e8c8a9;
  border-radius: var(--radius-sm);
  font-size: 12.5px;
  color: var(--warn);
  line-height: 1.5;
}
.settings-warning.show { display: block; }

.settings-reset {
  display: inline-block;
  margin-top: 8px;
  background: none;
  border: none;
  padding: 0;
  font-size: 13px;
  font-family: var(--font);
  color: var(--accent);
  cursor: pointer;
  border-bottom: 1px solid var(--accent-light);
  transition: border-color 0.15s;
}
.settings-reset:hover {
  border-bottom-color: var(--accent);
}
.settings-reset:disabled {
  color: var(--text3);
  border-bottom-color: transparent;
  cursor: not-allowed;
}

@media (max-width: 420px) {
  #settings-panel { width: 100vw; max-width: 100vw; }
}