/* ============================================================
   Quantix Scientific Calculator — style.css
   Author: Senior Full-Stack Dev
   Design: Dark-first glassmorphism with neon glow accents
   ============================================================ */

/* ── Custom Properties ── */
:root {
  --bg-base: #06070f;
  --bg-surface: #111827;
  --bg-glass: #111827;
  --bg-glass-hover: #1a2235;

  --accent-primary: #00d4ff;
  --accent-secondary: #a855f7;
  --accent-purple: #c084fc;
  --accent-pink: #f472b6;
  --accent-danger: #ff4757;
  --accent-success: #00e5a0;
  --accent-warn: #ffd32a;

  --btn-base: #1a2235;
  --btn-hover: #243047;

  --text-primary: #f0f4ff;
  --text-secondary: #94a3b8;
  --text-dim: #3d4f6a;

  --border-subtle: rgba(255,255,255,0.07);
  --border-glass: rgba(0,212,255,0.22);

  --glow-cyan:   0 0 18px rgba(0,212,255,0.50), 0 0 36px rgba(0,212,255,0.18);
  --glow-purple: 0 0 18px rgba(168,85,247,0.50), 0 0 36px rgba(168,85,247,0.18);
  --glow-pink:   0 0 16px rgba(244,114,182,0.45);
  --glow-red:    0 0 16px rgba(255,71,87,0.45);

  --radius-sm: 8px;
  --radius-md: 14px;
  --radius-lg: 22px;
  --radius-xl: 32px;

  --font-display: 'Playfair Display', Georgia, serif;
  --font-mono:    'Courier New', 'Lucida Console', monospace;
  --font-ui:      'Georgia', 'Times New Roman', serif;
  --font-label:   'Trebuchet MS', 'Arial', sans-serif;
  --font-heading: 'Palatino Linotype', 'Book Antiqua', Palatino, serif;
  --font-btn:     'Garamond', 'Georgia', serif;

  --transition: all 0.2s cubic-bezier(0.4, 0, 0.2, 1);
  --transition-slow: all 0.4s cubic-bezier(0.4, 0, 0.2, 1);
}

[data-theme="light"] {
  --bg-base: #eef2ff;
  --bg-surface: rgba(0,0,0,0.04);
  --bg-glass: rgba(255,255,255,0.88);
  --bg-glass-hover: rgba(255,255,255,0.97);

  --btn-base: #e4e9f5;
  --btn-hover: #d3daee;

  --text-primary: #0d1117;
  --text-secondary: #374151;
  --text-dim: #6b7280;

  --border-subtle: rgba(0,0,0,0.09);
  --border-glass: rgba(0,212,255,0.30);
  --glow-cyan: 0 2px 20px rgba(0,212,255,0.25);
}

/* ── Reset ── */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { font-size: 16px; }
body {
  font-family: var(--font-ui);
  font-weight: 500;
  font-size: 17px;
  background: var(--bg-base);
  color: var(--text-primary);
  min-height: 100vh;
  overflow-x: hidden;
  transition: background 0.4s, color 0.4s;
  display: flex;
  flex-direction: column;
  align-items: center;
}

/* ── Ambient Background ── */
.ambient-bg {
  position: fixed;
  inset: 0;
  pointer-events: none;
  z-index: 0;
  overflow: hidden;
}
.orb {
  position: absolute;
  border-radius: 50%;
  filter: blur(80px);
  opacity: 0.25;
  animation: floatOrb 20s ease-in-out infinite;
}
.orb-1 {
  width: 600px; height: 600px;
  background: radial-gradient(circle, #00d4ff, transparent);
  top: -200px; left: -200px;
  animation-delay: 0s;
}
.orb-2 {
  width: 500px; height: 500px;
  background: radial-gradient(circle, #a855f7, transparent);
  bottom: -150px; right: -150px;
  animation-delay: -7s;
}
.orb-3 {
  width: 400px; height: 400px;
  background: radial-gradient(circle, #f472b6, transparent);
  top: 50%; left: 50%;
  transform: translate(-50%, -50%);
  animation-delay: -14s;
  opacity: 0.10;
}
@keyframes floatOrb {
  0%, 100% { transform: translate(0, 0) scale(1); }
  33% { transform: translate(30px, -40px) scale(1.05); }
  66% { transform: translate(-20px, 30px) scale(0.95); }
}

/* ── App Wrapper ── */
.app-wrapper {
  position: relative;
  z-index: 1;
  width: 100%;
  max-width: 1100px;
  margin: 0 auto;
  padding: 20px 16px 40px;
}

/* ── Header ── */
.app-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 16px 24px;
  margin-bottom: 24px;
  background: var(--bg-glass);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-lg);
  backdrop-filter: blur(20px);
}
.brand {
  display: flex;
  align-items: center;
  gap: 12px;
}
.brand-icon {
  font-size: 28px;
  background: linear-gradient(135deg, #00d4ff, #a855f7);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  filter: drop-shadow(0 0 10px rgba(0,212,255,0.5));
  animation: hexSpin 8s linear infinite;
}
@keyframes hexSpin {
  0% { transform: rotate(0deg); }
  100% { transform: rotate(360deg); }
}
.brand-name {
  font-family: var(--font-display);
  font-size: 1.5rem;
  font-weight: 900;
  letter-spacing: 2px;
  background: linear-gradient(90deg, #00d4ff 0%, #a855f7 60%, #f472b6 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  filter: drop-shadow(0 0 12px rgba(0,212,255,0.35));
}
.brand-sub {
  font-family: var(--font-ui);
  font-size: 0.72rem;
  font-weight: 500;
  color: var(--text-secondary);
  letter-spacing: 1.5px;
  text-transform: uppercase;
  border-left: 1px solid var(--border-subtle);
  padding-left: 12px;
}
.header-controls {
  display: flex;
  gap: 10px;
}

/* ── Live Clock ── */
.header-clock {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  padding: 8px 20px;
  background: rgba(14,165,233,0.06);
  border: 1px solid rgba(14,165,233,0.20);
  border-radius: var(--radius-md);
  gap: 2px;
  min-width: 170px;
}
.clock-time {
  font-family: var(--font-mono);
  font-size: 1.15rem;
  font-weight: 600;
  color: var(--accent-primary);
  letter-spacing: 3px;
  line-height: 1.2;
}
.clock-date {
  font-family: var(--font-ui);
  font-size: 0.65rem;
  font-weight: 500;
  color: var(--text-secondary);
  letter-spacing: 1px;
  text-transform: uppercase;
}

@media (max-width: 700px) {
  .header-clock { display: none; }
}
.icon-btn {
  width: 40px; height: 40px;
  background: var(--bg-surface);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-sm);
  color: var(--text-secondary);
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: var(--transition);
}
.icon-btn svg { width: 18px; height: 18px; }
.icon-btn:hover {
  background: var(--bg-glass);
  border-color: var(--accent-primary);
  color: var(--accent-primary);
  box-shadow: var(--glow-cyan);
}

/* ── Main Layout ── */
.main-layout {
  display: flex;
  gap: 20px;
  align-items: flex-start;
}

/* ── History Panel ── */
.history-panel {
  width: 260px;
  flex-shrink: 0;
  background: var(--bg-glass);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-lg);
  backdrop-filter: blur(20px);
  overflow: hidden;
  max-height: 700px;
  display: flex;
  flex-direction: column;
  transform: translateX(-300px);
  opacity: 0;
  pointer-events: none;
  transition: var(--transition-slow);
  position: absolute;
  left: 0;
  top: 0;
  z-index: 10;
}
.history-panel.open {
  transform: translateX(0);
  opacity: 1;
  pointer-events: all;
  position: relative;
}
.panel-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 16px 20px;
  border-bottom: 1px solid var(--border-subtle);
  font-family: var(--font-ui);
  font-size: 0.7rem;
  letter-spacing: 2px;
  color: var(--text-secondary);
  text-transform: uppercase;
}
.clear-history-btn {
  background: transparent;
  border: none;
  color: var(--accent-danger);
  font-family: var(--font-ui);
  font-size: 0.75rem;
  cursor: pointer;
  transition: var(--transition);
  padding: 4px 8px;
  border-radius: var(--radius-sm);
}
.clear-history-btn:hover { background: rgba(255,71,87,0.15); }
.history-list {
  list-style: none;
  overflow-y: auto;
  flex: 1;
  padding: 12px;
  display: flex;
  flex-direction: column;
  gap: 8px;
}
.history-list::-webkit-scrollbar { width: 4px; }
.history-list::-webkit-scrollbar-track { background: transparent; }
.history-list::-webkit-scrollbar-thumb { background: var(--border-subtle); border-radius: 2px; }
.history-empty {
  color: var(--text-dim);
  font-size: 0.85rem;
  text-align: center;
  padding: 20px 0;
}
.history-item {
  background: var(--bg-surface);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-sm);
  padding: 10px 12px;
  cursor: pointer;
  transition: var(--transition);
  animation: slideIn 0.3s ease-out;
}
.history-item:hover {
  background: var(--bg-glass-hover);
  border-color: var(--accent-primary);
  transform: translateX(4px);
}
.history-item .h-expr {
  font-size: 0.78rem;
  color: var(--text-secondary);
  font-family: var(--font-mono);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}
.history-item .h-result {
  font-size: 1rem;
  color: var(--accent-primary);
  font-family: var(--font-mono);
  font-weight: 600;
}
@keyframes slideIn {
  from { opacity: 0; transform: translateY(-10px); }
  to   { opacity: 1; transform: translateY(0); }
}

/* ── Calculator Main Card ── */
.calculator {
  flex: 1;
  background: var(--bg-glass);
  border: 1px solid var(--border-glass);
  border-radius: var(--radius-xl);
  backdrop-filter: blur(30px);
  box-shadow: 0 24px 80px rgba(0,0,0,0.4), inset 0 1px 0 rgba(255,255,255,0.1);
  overflow: visible;
}

/* ── Display ── */
.display-wrapper {
  background: linear-gradient(135deg, rgba(0,212,255,0.06), rgba(168,85,247,0.07), rgba(244,114,182,0.04));
  border-bottom: 1px solid var(--border-subtle);
  padding: 24px;
}
.display-panel {
  background: rgba(0,0,0,0.45);
  border: 1px solid var(--border-glass);
  border-radius: var(--radius-lg);
  padding: 20px 24px;
  position: relative;
  min-height: 120px;
  display: flex;
  flex-direction: column;
  justify-content: flex-end;
  background-image: linear-gradient(
    transparent 50%,
    rgba(0,212,255,0.012) 50%
  );
  background-size: 100% 4px;
  box-shadow: inset 0 0 30px rgba(0,212,255,0.04);
}
.display-status {
  position: absolute;
  top: 12px; left: 16px; right: 40px;
  display: flex;
  gap: 12px;
  align-items: center;
}
.mem-indicator {
  font-family: var(--font-ui);
  font-size: 0.6rem;
  color: var(--accent-warn);
  letter-spacing: 1px;
  text-shadow: 0 0 10px var(--accent-warn);
}
.angle-mode {
  font-family: var(--font-ui);
  font-size: 0.55rem;
  color: var(--text-secondary);
  letter-spacing: 2px;
  border: 1px solid var(--border-subtle);
  padding: 2px 6px;
  border-radius: 4px;
}
.voice-indicator {
  font-size: 0.7rem;
  opacity: 0;
  transition: var(--transition);
}
.voice-indicator.active { opacity: 1; animation: pulse 1s infinite; }
@keyframes pulse {
  0%, 100% { transform: scale(1); }
  50% { transform: scale(1.2); }
}
.display-expression {
  font-family: var(--font-mono);
  font-size: clamp(1.2rem, 4vw, 2rem);
  color: var(--text-primary);
  text-align: right;
  word-break: break-all;
  line-height: 1.2;
  min-height: 2.4em;
  transition: font-size 0.2s;
}
.display-expression.error { color: var(--accent-danger); animation: shake 0.3s ease; }
@keyframes shake {
  0%, 100% { transform: translateX(0); }
  25% { transform: translateX(-8px); }
  75% { transform: translateX(8px); }
}
.display-result {
  font-family: var(--font-mono);
  font-size: clamp(0.8rem, 2.5vw, 1rem);
  color: var(--accent-primary);
  text-align: right;
  flex: 1;
  min-height: 1.4em;
  opacity: 0.85;
  letter-spacing: 1px;
}
/* Digit counter badge — total digits (blue) */
.digit-count {
  font-family: 'Trebuchet MS', Arial, sans-serif;
  font-size: 0.72rem;
  font-weight: 800;
  letter-spacing: 0.8px;
  color: #00c8f0;
  background: rgba(0,200,240,0.18);
  border: 1.5px solid rgba(0,200,240,0.55);
  padding: 3px 11px;
  border-radius: 12px;
  transition: var(--transition);
  white-space: nowrap;
}
.digit-count.has-digits {
  color: #00e5ff;
  border-color: #00c8f0;
  background: rgba(0,212,255,0.22);
  box-shadow: 0 0 8px rgba(0,212,255,0.30);
}

/* Number counter badge — operand count (green) */
.number-count {
  font-family: 'Trebuchet MS', Arial, sans-serif;
  font-size: 0.72rem;
  font-weight: 800;
  letter-spacing: 0.8px;
  color: #10d98a;
  background: rgba(16,217,138,0.16);
  border: 1.5px solid rgba(16,217,138,0.50);
  padding: 3px 11px;
  border-radius: 12px;
  transition: var(--transition);
  white-space: nowrap;
}
.number-count.has-digits {
  color: #00f5a0;
  border-color: #10d98a;
  background: rgba(16,217,138,0.22);
  box-shadow: 0 0 8px rgba(16,185,129,0.30);
}

/* Result line row: = 121  [3d] */
.display-result-row {
  display: flex;
  align-items: center;
  justify-content: flex-end;
  gap: 8px;
  min-height: 1.4em;
}

/* Answer digit-count badge next to = result */
.ans-digit-count {
  font-family: var(--font-ui);
  font-size: 0.52rem;
  font-weight: 700;
  letter-spacing: 0.5px;
  color: var(--accent-warn);
  background: rgba(245,158,11,0.12);
  border: 1px solid rgba(245,158,11,0.32);
  padding: 2px 7px;
  border-radius: 8px;
  opacity: 0;
  transition: var(--transition);
  white-space: nowrap;
  flex-shrink: 0;
}
.ans-digit-count.visible { opacity: 1; }


/* Display bottom row — holds copy button flush to right */
.display-bottom-row {
  display: flex;
  justify-content: flex-end;
  margin-top: 8px;
}
.copy-btn {
  display: flex;
  align-items: center;
  gap: 5px;
  padding: 5px 12px;
  background: rgba(14,165,233,0.08);
  border: 1px solid var(--border-glass);
  border-radius: 6px;
  color: var(--text-secondary);
  cursor: pointer;
  font-family: var(--font-mono);
  font-size: 0.7rem;
  font-weight: 700;
  letter-spacing: 1px;
  transition: var(--transition);
}
.copy-btn svg { width: 13px; height: 13px; flex-shrink: 0; }
.copy-btn:hover {
  color: var(--accent-primary);
  border-color: var(--accent-primary);
  background: rgba(14,165,233,0.16);
  box-shadow: var(--glow-cyan);
}

/* Advanced clear button */
.adv-clear-btn {
  padding: 10px 14px;
  background: rgba(239,68,68,0.08);
  border: 1px solid rgba(239,68,68,0.22);
  border-radius: var(--radius-sm);
  color: #f87171;
  font-family: var(--font-mono);
  font-size: 0.85rem;
  font-weight: 700;
  cursor: pointer;
  transition: var(--transition);
  flex-shrink: 0;
}
.adv-clear-btn:hover {
  background: rgba(239,68,68,0.18);
  box-shadow: var(--glow-red);
  transform: translateY(-1px);
}

/* ── Tab Navigation ── */
.tab-nav {
  display: flex;
  border-bottom: 1px solid var(--border-subtle);
  overflow-x: auto;
  scrollbar-width: none;
}
.tab-nav::-webkit-scrollbar { display: none; }
.tab-btn {
  flex: 1;
  min-width: 80px;
  padding: 12px 8px;
  background: transparent;
  border: none;
  border-bottom: 2px solid transparent;
  color: var(--text-secondary);
  font-family: var(--font-ui);
  font-size: 0.68rem;
  font-weight: 600;
  letter-spacing: 1px;
  text-transform: uppercase;
  cursor: pointer;
  transition: var(--transition);
  white-space: nowrap;
}
.tab-btn:hover { color: var(--text-primary); background: var(--bg-surface); }
.tab-btn.active {
  color: var(--accent-primary);
  border-bottom-color: var(--accent-primary);
  background: rgba(0,212,255,0.06);
  text-shadow: 0 0 12px rgba(0,212,255,0.5);
}

/* ── Tab Content ── */
.tab-content { display: none; padding: 20px; }
.tab-content.active {
  display: flex;
  flex-direction: column;
  gap: 0;
}

/* ── Button Grids ── */
.btn-grid {
  display: grid;
  gap: 10px;
}
.standard-grid {
  grid-template-columns: repeat(4, 1fr);
}
.sci-grid {
  grid-template-columns: repeat(6, 1fr);
}
.extra-grid {
  grid-template-columns: repeat(6, 1fr);
}

/* ── Calculator Buttons ── */
.calc-btn {
  position: relative;
  overflow: hidden;
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-sm);
  background: var(--btn-base);
  color: var(--text-primary);
  font-family: var(--font-btn);
  font-size: 1.05rem;
  font-weight: 600;
  padding: 16px 8px;
  cursor: pointer;
  transition: var(--transition);
  letter-spacing: 0.5px;
  display: flex;
  align-items: center;
  justify-content: center;
  user-select: none;
  -webkit-tap-highlight-color: transparent;
  backdrop-filter: blur(8px);
}
.calc-btn:hover {
  background: var(--btn-hover);
  transform: translateY(-2px);
  box-shadow: 0 4px 16px rgba(0,0,0,0.3);
}
.calc-btn:active {
  transform: translateY(1px) scale(0.96);
  box-shadow: none;
}

/* Ripple */
.calc-btn::after {
  content: '';
  position: absolute;
  inset: 0;
  background: radial-gradient(circle, rgba(255,255,255,0.3), transparent 70%);
  opacity: 0;
  transform: scale(0);
  transition: transform 0.4s ease, opacity 0.4s ease;
}
.calc-btn.ripple::after { transform: scale(2); opacity: 0; transition: transform 0.6s ease, opacity 0.6s ease; }

/* Button Variants */
.num-btn {
  background: var(--btn-base);
  font-size: 1.1rem;
  font-weight: 700;
}
.num-btn:hover {
  background: var(--btn-hover);
  box-shadow: 0 4px 12px rgba(0,0,0,0.25);
}

.op-btn {
  background: rgba(0,212,255,0.10);
  border-color: rgba(0,212,255,0.28);
  color: #67e8f9;
  font-size: 1.3rem;
}
.op-btn:hover {
  background: rgba(0,212,255,0.22);
  box-shadow: 0 0 18px rgba(0,212,255,0.35);
  color: #00d4ff;
}

.eq-btn {
  background: linear-gradient(135deg, #00d4ff 0%, #7c3aed 70%, #a855f7 100%);
  border: none;
  color: #fff;
  font-size: 1.4rem;
  font-weight: 700;
  box-shadow: 0 0 20px rgba(0,212,255,0.40), 0 0 40px rgba(168,85,247,0.20);
}
.eq-btn:hover {
  background: linear-gradient(135deg, #22e5ff 0%, #9333ea 70%, #c084fc 100%);
  box-shadow: 0 0 30px rgba(0,212,255,0.55), 0 0 50px rgba(168,85,247,0.30);
  transform: translateY(-3px);
}

.special-btn {
  background: rgba(255,71,87,0.10);
  border-color: rgba(255,71,87,0.28);
  color: #ff6b7a;
  font-weight: 600;
}
.special-btn:hover {
  background: rgba(255,71,87,0.22);
  box-shadow: var(--glow-red);
  color: #ff4757;
}

.mem-btn {
  background: rgba(244,114,182,0.08);
  border-color: rgba(244,114,182,0.22);
  color: #f9a8d4;
  font-size: 0.8rem;
  letter-spacing: 0.5px;
}
.mem-btn:hover {
  background: rgba(244,114,182,0.20);
  box-shadow: var(--glow-pink);
  color: #f472b6;
}

.sci-btn {
  background: rgba(60, 30, 100, 0.55);
  border-color: rgba(168,85,247,0.25);
  color: #d8b4fe;
  font-size: 0.88rem;
  padding: 18px 6px;
  min-height: 56px;
  letter-spacing: 0.3px;
}
.sci-btn:hover {
  background: rgba(124,58,237,0.38);
  box-shadow: 0 0 18px rgba(168,85,247,0.40), inset 0 1px 0 rgba(255,255,255,0.08);
  color: #f3e8ff;
  border-color: rgba(168,85,247,0.55);
  transform: translateY(-2px);
}

.span-2 { grid-column: span 2; }

/* ── Angle Toggle ── */
.angle-toggle-row {
  display: flex;
  gap: 8px;
  margin-bottom: 14px;
}
.angle-btn {
  padding: 6px 20px;
  background: var(--bg-surface);
  border: 1px solid var(--border-subtle);
  border-radius: 100px;
  color: var(--text-secondary);
  font-family: var(--font-ui);
  font-size: 0.6rem;
  letter-spacing: 2px;
  cursor: pointer;
  transition: var(--transition);
}
.angle-btn.active {
  background: rgba(0,212,255,0.15);
  border-color: var(--accent-primary);
  color: var(--accent-primary);
  box-shadow: 0 0 10px rgba(0,212,255,0.25);
}

/* ── Advanced Section ── */
.advanced-section {
  margin-bottom: 20px;
  padding: 20px;
  background: var(--bg-surface);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  display: block;
  width: 100%;
  box-sizing: border-box;
}
.section-label {
  font-family: var(--font-label);
  font-size: 0.82rem;
  font-weight: 700;
  letter-spacing: 1.5px;
  text-transform: uppercase;
  color: var(--accent-primary);
  margin-bottom: 16px;
  display: flex;
  align-items: center;
  gap: 12px;
}
.section-hint {
  font-family: var(--font-ui);
  font-size: 0.78rem;
  letter-spacing: 0;
  color: var(--text-dim);
  font-weight: 400;
  text-transform: none;
}
.advanced-input-row {
  display: flex;
  gap: 10px;
  align-items: center;
  flex-wrap: wrap;
}
.adv-input {
  flex: 1;
  min-width: 120px;
  background: rgba(0,0,0,0.3);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-sm);
  padding: 10px 14px;
  color: var(--text-primary);
  font-family: var(--font-mono);
  font-size: 0.85rem;
  transition: var(--transition);
}
.adv-input::placeholder { color: var(--text-dim); }
.adv-input:focus {
  outline: none;
  border-color: var(--accent-primary);
  box-shadow: 0 0 12px rgba(0,229,255,0.2);
}
.adv-small { flex: 0 0 90px; min-width: unset; }
.adv-btn {
  padding: 10px 22px;
  background: linear-gradient(135deg, var(--accent-secondary), #9333ea);
  border: none;
  border-radius: var(--radius-sm);
  color: #fff;
  font-family: var(--font-ui);
  font-size: 0.65rem;
  letter-spacing: 2px;
  cursor: pointer;
  transition: var(--transition);
}
.adv-btn:hover {
  box-shadow: var(--glow-purple);
  transform: translateY(-2px);
}
.adv-result {
  margin-top: 12px;
  font-family: var(--font-mono);
  font-size: 0.92rem;
  color: var(--accent-success);
  min-height: 1.4em;
  padding: 10px 14px;
  background: rgba(16,185,129,0.05);
  border-radius: var(--radius-sm);
  border-left: 3px solid var(--accent-success);
  font-weight: 700;
  display: flex;
  flex-direction: column;
  gap: 6px;
}
.adv-result-row {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
  align-items: baseline;
  line-height: 1.5;
}
.adv-result-label {
  font-family: var(--font-ui);
  font-size: 0.55rem;
  letter-spacing: 1.5px;
  text-transform: uppercase;
  color: var(--text-secondary);
  background: rgba(255,255,255,0.06);
  padding: 2px 8px;
  border-radius: 4px;
  flex-shrink: 0;
}
.adv-result-error {
  color: var(--accent-danger);
  border-left-color: var(--accent-danger);
}

/* ── Advanced deg/rad toggle — hidden until trig detected ── */
.adv-angle-row {
  display: none;   /* hidden by default */
  align-items: center;
  gap: 10px;
  margin-bottom: 12px;
  flex-wrap: wrap;
  animation: fadeInRow 0.25s ease;
}
.adv-angle-row.visible {
  display: flex;   /* shown by JS when trig found */
}
@keyframes fadeInRow {
  from { opacity: 0; transform: translateY(-4px); }
  to   { opacity: 1; transform: translateY(0); }
}
.adv-angle-label {
  font-family: var(--font-ui);
  font-size: 0.6rem;
  letter-spacing: 1.5px;
  text-transform: uppercase;
  color: var(--text-secondary);
  white-space: nowrap;
}
.adv-angle-toggle {
  display: flex;
  border: 1px solid var(--border-subtle);
  border-radius: 8px;
  overflow: hidden;
}
.adv-angle-btn {
  padding: 5px 14px;
  background: transparent;
  border: none;
  font-family: var(--font-ui);
  font-size: 0.6rem;
  font-weight: 700;
  letter-spacing: 1.5px;
  color: var(--text-dim);
  cursor: pointer;
  transition: var(--transition);
}
.adv-angle-btn.active {
  background: rgba(0,240,255,0.18);
  color: var(--accent-primary);
  box-shadow: inset 0 0 8px rgba(0,240,255,0.15);
}
.adv-angle-hint {
  font-size: 0.68rem;
  color: var(--text-dim);
  font-family: var(--font-ui);
  font-style: italic;
}

/* ── Converter ── */
.converter-panel {
  padding: 8px;
}
.conv-input-group {
  margin-bottom: 16px;
}
.conv-input-group label,
.conv-base-select label {
  display: block;
  font-size: 0.7rem;
  letter-spacing: 1.5px;
  text-transform: uppercase;
  color: var(--text-secondary);
  margin-bottom: 8px;
  font-family: var(--font-ui);
}
.conv-input {
  width: 100%;
  background: rgba(0,0,0,0.3);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-sm);
  padding: 14px 18px;
  color: var(--text-primary);
  font-family: var(--font-mono);
  font-size: 1.1rem;
  transition: var(--transition);
}
.conv-input:focus {
  outline: none;
  border-color: var(--accent-primary);
  box-shadow: 0 0 15px rgba(0,229,255,0.2);
}
.conv-base-select { margin-bottom: 20px; }
.base-btns {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
}
.base-btn {
  padding: 8px 16px;
  background: var(--bg-surface);
  border: 1px solid var(--border-subtle);
  border-radius: 100px;
  color: var(--text-secondary);
  font-family: var(--font-ui);
  font-size: 0.8rem;
  cursor: pointer;
  transition: var(--transition);
}
.base-btn.active {
  background: rgba(0,229,255,0.12);
  border-color: var(--accent-primary);
  color: var(--accent-primary);
}
.conv-results {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 12px;
}
.conv-result-card {
  background: var(--bg-surface);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  padding: 16px;
  transition: var(--transition);
  cursor: pointer;
}
.conv-result-card:hover {
  border-color: var(--accent-primary);
  box-shadow: var(--glow-cyan);
  transform: translateY(-2px);
}
.conv-label {
  display: block;
  font-size: 0.65rem;
  letter-spacing: 2px;
  text-transform: uppercase;
  color: var(--text-secondary);
  font-family: var(--font-ui);
  margin-bottom: 8px;
}
.conv-value {
  display: block;
  font-family: var(--font-mono);
  font-size: 0.95rem;
  color: var(--accent-primary);
  word-break: break-all;
  line-height: 1.4;
}

/* ── Graph Panel (original layout, Desmos-quality engine) ── */
.graph-panel { padding: 4px; }

.graph-input-row {
  display: flex;
  gap: 10px;
  align-items: center;
  margin-bottom: 12px;
  flex-wrap: wrap;
}
/* ── Function list (Desmos-style rows) ── */
.fn-list {
  display: flex;
  flex-direction: column;
  gap: 6px;
  margin-bottom: 8px;
  max-height: 300px;
  overflow-y: auto;
  padding-right: 2px;
}
.fn-list::-webkit-scrollbar { width: 4px; }
.fn-list::-webkit-scrollbar-thumb { background: var(--border-subtle); border-radius: 2px; }

.fn-row {
  display: flex;
  align-items: center;
  gap: 8px;
  background: rgba(255,255,255,0.04);
  border: 1px solid var(--border-subtle);
  border-left: 3px solid transparent;
  border-radius: var(--radius-sm);
  padding: 7px 10px;
  transition: border-color 0.2s, box-shadow 0.2s;
  animation: fnRowIn 0.2s ease-out;
}
@keyframes fnRowIn {
  from { opacity: 0; transform: translateY(-6px); }
  to   { opacity: 1; transform: translateY(0); }
}
.fn-row:focus-within {
  box-shadow: 0 0 12px rgba(0,240,255,0.15);
}

/* Type toggle pill: x / y */
.fn-type-toggle {
  display: flex;
  border: 1px solid var(--border-subtle);
  border-radius: 6px;
  overflow: hidden;
  flex-shrink: 0;
}
.fn-type-btn {
  background: transparent;
  border: none;
  padding: 3px 8px;
  font-family: var(--font-mono);
  font-size: 0.72rem;
  font-weight: 700;
  color: var(--text-dim);
  cursor: pointer;
  transition: var(--transition);
  line-height: 1.4;
}
.fn-type-btn.active {
  background: rgba(0,240,255,0.15);
  color: var(--accent-primary);
}

.fn-row-label {
  font-family: var(--font-mono);
  font-size: 0.78rem;
  font-weight: 700;
  color: var(--text-secondary);
  white-space: nowrap;
  min-width: 44px;
}
.fn-row-input {
  flex: 1;
  background: transparent;
  border: none;
  outline: none;
  color: var(--text-primary);
  font-family: var(--font-mono);
  font-size: 0.9rem;
  font-weight: 700;
  caret-color: var(--accent-primary);
}
.fn-row-input::placeholder { color: var(--text-dim); font-weight: 400; }
.fn-row-remove {
  background: transparent;
  border: none;
  color: var(--text-dim);
  cursor: pointer;
  font-size: 0.8rem;
  line-height: 1;
  padding: 2px 5px;
  border-radius: 4px;
  transition: var(--transition);
  flex-shrink: 0;
}
.fn-row-remove:hover { color: var(--accent-danger); background: rgba(255,71,87,0.12); }

.add-fn-btn {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 7px 16px;
  margin-bottom: 12px;
  background: rgba(0,240,255,0.06);
  border: 1px dashed rgba(0,240,255,0.3);
  border-radius: var(--radius-sm);
  color: var(--accent-primary);
  font-family: var(--font-mono);
  font-size: 0.8rem;
  font-weight: 700;
  cursor: pointer;
  transition: var(--transition);
  letter-spacing: 0.5px;
}
.add-fn-btn:hover {
  background: rgba(0,240,255,0.13);
  border-style: solid;
}

/* Graph theme toggle button */
.graph-theme-btn { font-size: 0.85rem !important; }

/* Graph canvas light mode */
.graph-canvas-wrap.graph-light {
  background: #ffffff;
}
.graph-canvas-wrap.graph-light #graphCanvas {
  filter: none;
}

/* Canvas wrapper — relative so overlay controls sit inside */
.graph-canvas-wrap {
  position: relative;
  width: 100%;
  height: 340px;
  border-radius: var(--radius-md);
  overflow: hidden;
  border: 1px solid var(--border-subtle);
  background: #0a0e1a;
  cursor: crosshair;
}
#graphCanvas {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  display: block;
}

/* Crosshair tooltip */
.graph-tooltip {
  position: absolute;
  background: rgba(0,0,0,0.88);
  border: 1px solid var(--accent-primary);
  border-radius: 6px;
  padding: 5px 10px;
  font-family: var(--font-mono);
  font-size: 0.75rem;
  font-weight: 700;
  color: var(--accent-primary);
  pointer-events: none;
  opacity: 0;
  transition: opacity 0.15s;
  white-space: nowrap;
  z-index: 10;
  box-shadow: 0 0 10px rgba(0,229,255,0.2);
}
.graph-tooltip.visible { opacity: 1; }

/* Zoom/pan overlay controls — top-right corner of canvas */
.graph-overlay-controls {
  position: absolute;
  top: 10px;
  right: 10px;
  display: flex;
  flex-direction: column;
  gap: 4px;
  z-index: 20;
}
.graph-ctrl-btn {
  width: 32px;
  height: 32px;
  background: rgba(0,0,0,0.6);
  border: 1px solid var(--border-glass);
  border-radius: var(--radius-sm);
  color: var(--text-primary);
  font-family: var(--font-mono);
  font-size: 1rem;
  font-weight: 700;
  cursor: pointer;
  transition: var(--transition);
  display: flex;
  align-items: center;
  justify-content: center;
  backdrop-filter: blur(6px);
}
.graph-ctrl-btn:hover {
  background: rgba(0,229,255,0.18);
  border-color: var(--accent-primary);
  color: var(--accent-primary);
  box-shadow: var(--glow-cyan);
}

.graph-hint {
  margin-top: 10px;
  font-size: 0.72rem;
  font-weight: 600;
  color: var(--text-dim);
  letter-spacing: 0.3px;
}

@media (max-width: 600px) {
  .graph-canvas-wrap { height: 260px; }
}

/* ── Voice Modal ── */
.voice-modal {
  position: fixed;
  inset: 0;
  background: rgba(0,0,0,0.7);
  backdrop-filter: blur(12px);
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 20px;
  z-index: 1000;
  opacity: 0;
  pointer-events: none;
  transition: var(--transition-slow);
}
.voice-modal.open { opacity: 1; pointer-events: all; }
.voice-pulse {
  width: 80px; height: 80px;
  border-radius: 50%;
  background: radial-gradient(circle, var(--accent-primary), transparent);
  box-shadow: 0 0 40px var(--accent-primary);
  animation: voicePulse 1.2s ease-in-out infinite;
}
@keyframes voicePulse {
  0%, 100% { transform: scale(1); opacity: 0.8; }
  50% { transform: scale(1.4); opacity: 1; }
}
.voice-modal p {
  color: var(--text-primary);
  font-family: var(--font-ui);
  font-size: 0.85rem;
  letter-spacing: 2px;
  text-transform: uppercase;
}
#voiceCancel {
  padding: 10px 28px;
  background: var(--accent-danger);
  border: none;
  border-radius: 100px;
  color: #fff;
  font-family: var(--font-ui);
  font-size: 0.9rem;
  cursor: pointer;
  transition: var(--transition);
}
#voiceCancel:hover { background: #ff6070; }

/* ── Scrollbar global ── */
::-webkit-scrollbar { width: 6px; }
::-webkit-scrollbar-track { background: transparent; }
::-webkit-scrollbar-thumb { background: var(--border-subtle); border-radius: 3px; }

/* ── Responsive ── */
@media (max-width: 900px) {
  .main-layout { flex-direction: column; }
  .history-panel {
    width: 100%;
    max-height: 300px;
    position: relative;
    transform: none;
    opacity: 0;
    pointer-events: none;
    max-height: 0;
    overflow: hidden;
  }
  .history-panel.open {
    opacity: 1;
    pointer-events: all;
    max-height: 300px;
  }
}
@media (max-width: 600px) {
  .brand-sub { display: none; }
  .sci-grid { grid-template-columns: repeat(4, 1fr); }
  .extra-grid { grid-template-columns: repeat(4, 1fr); }
  .conv-results { grid-template-columns: 1fr; }
  .calc-btn { padding: 13px 6px; font-size: 0.85rem; }
  .sci-btn { font-size: 0.7rem; padding: 10px 3px; }
  .display-expression { font-size: 1.3rem; }
}
@media (max-width: 420px) {
  .standard-grid { grid-template-columns: repeat(4, 1fr); gap: 7px; }
  .tab-btn { font-size: 0.45rem; padding: 10px 4px; }
}

/* ── Utility ── */
.no-anim { animation: none !important; transition: none !important; }

/* Toast notification */
.toast {
  position: fixed;
  bottom: 30px;
  left: 50%;
  transform: translateX(-50%) translateY(20px);
  background: linear-gradient(90deg, #00d4ff, #a855f7);
  color: #fff;
  padding: 10px 24px;
  border-radius: 100px;
  font-family: var(--font-ui);
  font-size: 0.7rem;
  letter-spacing: 1.5px;
  text-transform: uppercase;
  z-index: 2000;
  opacity: 0;
  transition: all 0.3s ease;
  pointer-events: none;
  box-shadow: 0 4px 20px rgba(0,212,255,0.35), 0 0 30px rgba(168,85,247,0.20);
  white-space: nowrap;
  max-width: 90vw;
  overflow: hidden;
  text-overflow: ellipsis;
}
.toast.show {
  opacity: 1;
  transform: translateX(-50%) translateY(0);
}

/* ── Light mode overrides — ensure strong visibility ── */
[data-theme="light"] .display-panel {
  background: rgba(255,255,255,0.9);
  background-image: none;
}
[data-theme="light"] .display-expression { color: #0d1117; }
[data-theme="light"] .display-result      { color: #0284c7; opacity: 1; }
[data-theme="light"] .angle-mode          { color: #374151; border-color: rgba(0,0,0,0.2); }
[data-theme="light"] .mem-indicator       { color: #b45309; }

[data-theme="light"] .num-btn  { color: #0d1117; background: #e2e8f0; border-color: rgba(0,0,0,0.12); }
[data-theme="light"] .num-btn:hover { background: #cbd5e1; }
[data-theme="light"] .op-btn   { color: #0284c7; background: rgba(14,165,233,0.12); border-color: rgba(14,165,233,0.3); }
[data-theme="light"] .mem-btn  { color: #7e22ce; background: rgba(168,85,247,0.10); border-color: rgba(168,85,247,0.25); }
[data-theme="light"] .sci-btn  { color: #6d28d9; background: rgba(168,85,247,0.10); border-color: rgba(168,85,247,0.28); }
[data-theme="light"] .sci-btn:hover { background: rgba(168,85,247,0.20); color: #5b21b6; }
[data-theme="light"] .special-btn { color: #dc2626; background: rgba(239,68,68,0.08); border-color: rgba(239,68,68,0.2); }
[data-theme="light"] .eq-btn   { color: #ffffff; }
[data-theme="light"] .calc-btn { color: #0d1117; }

[data-theme="light"] .tab-btn  { color: #374151; }
[data-theme="light"] .tab-btn.active { color: var(--accent-primary); }
[data-theme="light"] .tab-btn:hover  { color: #0d1117; }

[data-theme="light"] .section-label  { color: #0284c7; }
[data-theme="light"] .adv-input      { color: #0d1117; background: rgba(0,0,0,0.04); border-color: rgba(0,0,0,0.15); }
[data-theme="light"] .adv-input::placeholder { color: #6b7280; }
[data-theme="light"] .advanced-section { background: rgba(0,0,0,0.03); border-color: rgba(0,0,0,0.08); }
[data-theme="light"] .conv-input  { color: #0d1117; background: rgba(0,0,0,0.04); }
[data-theme="light"] .conv-value  { color: #0284c7; }
[data-theme="light"] .conv-label  { color: #374151; }

[data-theme="light"] .per-num-badge   { color: #0284c7; background: rgba(14,165,233,0.10); }
[data-theme="light"] .digit-count {
  color: #0369a1;
  background: rgba(3,105,161,0.12);
  border-color: rgba(3,105,161,0.55);
}
[data-theme="light"] .digit-count.has-digits {
  color: #0369a1;
  background: rgba(3,105,161,0.18);
  border-color: #0369a1;
  box-shadow: 0 0 6px rgba(3,105,161,0.25);
}
[data-theme="light"] .number-count {
  color: #047857;
  background: rgba(4,120,87,0.12);
  border-color: rgba(4,120,87,0.50);
}
[data-theme="light"] .number-count.has-digits {
  color: #047857;
  background: rgba(4,120,87,0.18);
  border-color: #047857;
  box-shadow: 0 0 6px rgba(4,120,87,0.20);
}
[data-theme="light"] .ans-digit-count { color: #b45309; background: rgba(245,158,11,0.10); }

[data-theme="light"] .brand-name { color: #0284c7; }
[data-theme="light"] .brand-sub  { color: #374151; }
[data-theme="light"] .copy-btn   { color: #374151; background: rgba(14,165,233,0.08); }
[data-theme="light"] .copy-btn:hover { color: #0284c7; }

[data-theme="light"] .fn-row-input { color: #0d1117; }
[data-theme="light"] .graph-fn-input { color: #0d1117; }
[data-theme="light"] .adv-result  { color: #065f46; background: rgba(16,185,129,0.06); border-color: #10b981; }
[data-theme="light"] .adv-result-label { color: #374151; }

/* ── Pending-sci indicator shown in display status bar ── */
.sci-pending-badge {
  display: inline-flex;
  align-items: center;
  gap: 5px;
  padding: 2px 8px;
  background: linear-gradient(90deg, rgba(168,85,247,0.18), rgba(0,212,255,0.12));
  border: 1px solid rgba(168,85,247,0.35);
  border-radius: 10px;
  font-family: var(--font-mono);
  font-size: 0.58rem;
  font-weight: 700;
  color: #c084fc;
  letter-spacing: 1px;
  animation: pendingPulse 2s ease-in-out infinite;
}
.sci-pending-badge .spb-icon { color: #00d4ff; }

@keyframes pendingPulse {
  0%, 100% { opacity: 1; }
  50% { opacity: 0.65; }
}

/* ── Num button hover shimmer ── */
.num-btn:hover {
  background: var(--btn-hover);
  box-shadow: 0 4px 14px rgba(0,212,255,0.10);
}

/* ── Calculator card border glow ── */
.calculator {
  border-color: rgba(0,212,255,0.18);
  box-shadow: 0 24px 80px rgba(0,0,0,0.5),
              0 0 0 1px rgba(168,85,247,0.06),
              inset 0 1px 0 rgba(255,255,255,0.06);
}

/* ============================================================
   NEW ADDITIONS — tooltips, π buttons, converter alert
   ============================================================ */

/* ── Function tooltip wrapper ── */
/* ── Extra-grid buttons: solid vibrant purple matching screenshots ── */
.extra-grid .calc-btn {
  font-size: 0.92rem;
  font-weight: 600;
  padding: 18px 6px;
  min-height: 56px;
  background: rgba(109, 40, 217, 0.75);
  border-color: rgba(139, 92, 246, 0.55);
  color: #ede9fe;
  letter-spacing: 0.3px;
  font-family: 'Times New Roman', Georgia, serif;
}
.extra-grid .calc-btn:hover {
  background: rgba(124,58,237,0.92);
  box-shadow: 0 0 20px rgba(139,92,246,0.50), inset 0 1px 0 rgba(255,255,255,0.12);
  color: #fff;
  border-color: rgba(167,139,250,0.7);
  transform: translateY(-2px);
}
/* AC button in extra grid keeps red */
.extra-grid .special-btn {
  background: rgba(255,71,87,0.15);
  border-color: rgba(255,71,87,0.35);
  color: #ff6b7a;
}
.extra-grid .special-btn:hover {
  background: rgba(255,71,87,0.30);
  color: #ff4757;
}
/* = button in extra grid keeps gradient */
.extra-grid .eq-btn {
  background: linear-gradient(135deg, #00d4ff 0%, #7c3aed 70%, #a855f7 100%);
  color: #fff;
  border: none;
}

/* ── Function tooltip wrapper ── */
.fn-tooltip-wrap {
  position: relative;
  display: contents;
}
.btn-grid .fn-tooltip-wrap {
  display: block;
  position: relative;
  width: 100%;
  height: 100%;
}
.btn-grid .fn-tooltip-wrap .calc-btn {
  width: 100%;
  height: 100%;
}

/* ── Vibrant gradient tooltip ── */
.fn-tooltip-wrap .fn-tooltip {
  display: none;
  position: fixed;
  z-index: 99999;
  width: 230px;
  background: linear-gradient(145deg,
    rgba(15, 8, 40, 0.98) 0%,
    rgba(30, 10, 65, 0.98) 45%,
    rgba(8, 18, 50, 0.98) 100%);
  border-radius: 13px;
  padding: 12px 15px;
  font-family: 'Times New Roman', Georgia, serif;
  font-size: 0.80rem;
  color: #cdd6f4;
  line-height: 1.6;
  pointer-events: none;
  box-shadow:
    0 0 0 1px rgba(124,58,237,0.5),
    0 0 0 3px rgba(0,212,255,0.08),
    0 0 24px rgba(124,58,237,0.35),
    0 0 48px rgba(0,212,255,0.10),
    0 16px 48px rgba(0,0,0,0.75);
  white-space: normal;
  animation: tooltipIn 0.15s cubic-bezier(0.34,1.56,0.64,1);
}
@keyframes tooltipIn {
  from { opacity: 0; transform: translateY(6px) scale(0.96); }
  to   { opacity: 1; transform: translateY(0) scale(1); }
}
/* Top shimmer bar */
.fn-tooltip-wrap .fn-tooltip::before {
  content: '';
  position: absolute;
  top: 0; left: 10px; right: 10px; height: 2px;
  background: linear-gradient(90deg,
    transparent,
    #00d4ff 20%,
    #a855f7 50%,
    #00d4ff 80%,
    transparent);
  border-radius: 2px 2px 0 0;
  opacity: 0.9;
}
/* Arrow pointing down — position controlled by JS */
.fn-tooltip-wrap .fn-tooltip::after {
  content: '';
  position: absolute;
  top: 100%;
  left: var(--arrow-left, 50%);
  transform: translateX(-50%);
  border: 7px solid transparent;
  border-top-color: rgba(124,58,237,0.55);
}
/* JS controls display — CSS hover is fallback only */
.fn-tooltip-wrap:hover .fn-tooltip { display: block; }

/* Title — cyan-purple gradient */
.fn-tooltip b {
  display: block;
  margin-bottom: 4px;
  font-size: 0.86rem;
  font-weight: 700;
  background: linear-gradient(90deg, #00d4ff 0%, #a855f7 60%, #f472b6 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  font-family: 'Times New Roman', Georgia, serif;
}
/* Syntax example pill */
.fn-tooltip-syn {
  display: block;
  margin-top: 7px;
  font-family: 'Times New Roman', Georgia, serif;
  font-size: 0.72rem;
  color: #67e8f9;
  background: linear-gradient(90deg,
    rgba(0,212,255,0.12),
    rgba(168,85,247,0.12));
  border: 1px solid rgba(0,212,255,0.22);
  border-radius: 7px;
  padding: 5px 9px;
  letter-spacing: 0.25px;
}

/* ── π Insert button ── */
.adv-input-wrap {
  position: relative;
  flex: 1;
  display: flex;
  align-items: center;
  min-width: 0;
}
.adv-input-wrap.adv-small { flex: 0 0 90px; }
.adv-input-wrap .adv-input { flex: 1; padding-right: 28px; }
.pi-insert-btn {
  position: absolute;
  right: 5px;
  top: 50%;
  transform: translateY(-50%);
  background: linear-gradient(135deg, rgba(0,212,255,0.18), rgba(168,85,247,0.18));
  border: 1px solid rgba(0,212,255,0.3);
  border-radius: 5px;
  color: #00d4ff;
  font-size: 0.85rem;
  font-weight: 700;
  width: 22px;
  height: 22px;
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  padding: 0;
  transition: background 0.15s, box-shadow 0.15s;
  line-height: 1;
}
.pi-insert-btn:hover {
  background: rgba(0,212,255,0.3);
  box-shadow: 0 0 8px rgba(0,212,255,0.4);
}

/* ── Converter validation alert ── */
#convAlert {
  display: none;
  background: rgba(239,68,68,0.10);
  border: 1px solid rgba(239,68,68,0.45);
  border-radius: 9px;
  padding: 10px 14px;
  margin-top: 10px;
  font-size: 0.80rem;
  color: #fca5a5;
  line-height: 1.55;
  font-family: var(--font-ui, sans-serif);
  animation: alertFadeIn 0.2s ease;
}
@keyframes alertFadeIn {
  from { opacity: 0; transform: translateY(-4px); }
  to   { opacity: 1; transform: translateY(0); }
}
[data-theme="light"] #convAlert {
  background: rgba(239,68,68,0.07);
  color: #b91c1c;
}

/* ============================================================
   DISTINCT FONTS PER UI PARAMETER  +  SIZE INCREASES
   ============================================================ */

/* ── Tab navigation labels → Trebuchet MS (clean sans) ── */
.tab-btn {
  font-family: 'Trebuchet MS', Arial, sans-serif !important;
  font-size: 0.82rem !important;
  font-weight: 700 !important;
  letter-spacing: 2px !important;
}

/* ── Display / result numbers → Courier New (monospaced, precise) ── */
.display-expr,
.display-result,
.calc-display,
.result-value {
  font-family: 'Courier New', 'Lucida Console', monospace !important;
  font-size: 2.4rem !important;
  font-weight: 600 !important;
}
.display-sub {
  font-family: 'Courier New', monospace !important;
  font-size: 1.1rem !important;
}

/* ── Calculator button labels → Garamond (elegant serif) ── */
.calc-btn, .sci-btn {
  font-family: 'Garamond', 'Book Antiqua', Georgia, serif !important;
  font-size: 1.08rem !important;
  font-weight: 600 !important;
}
.num-btn {
  font-family: 'Garamond', Georgia, serif !important;
  font-size: 1.25rem !important;
  font-weight: 700 !important;
}
.op-btn {
  font-family: 'Palatino Linotype', Palatino, Georgia, serif !important;
  font-size: 1.4rem !important;
  font-weight: 600 !important;
}

/* ── Section headings → Palatino (distinguished serif) ── */
.section-label,
.mt-card-title,
.advanced-section h3 {
  font-family: 'Palatino Linotype', 'Book Antiqua', Palatino, serif !important;
  font-size: 0.85rem !important;
  letter-spacing: 2px !important;
}

/* ── Input fields → Georgia (readable serif) ── */
.adv-input,
.mt-input,
input[type="text"],
input[type="number"] {
  font-family: 'Georgia', 'Times New Roman', serif !important;
  font-size: 1.0rem !important;
  font-weight: 500 !important;
}

/* ── Result output → Courier New (monospaced for values) ── */
.adv-result,
.mt-result,
.adv-result-row,
.result-row {
  font-family: 'Courier New', 'Lucida Console', monospace !important;
  font-size: 1.0rem !important;
  font-weight: 600 !important;
}

/* ── Labels / badges / metadata → Trebuchet MS ── */
.adv-result-label,
.mt-result-label,
.conv-label,
.badge,
.angle-btn,
.adv-angle-label,
.adv-angle-hint {
  font-family: 'Trebuchet MS', Arial, sans-serif !important;
  font-size: 0.78rem !important;
  letter-spacing: 1.2px !important;
}

/* ── History items → Georgia ── */
.history-expr,
.history-item {
  font-family: 'Georgia', serif !important;
  font-size: 0.95rem !important;
}

/* ── Tooltip title → Palatino, body → Georgia ── */
.fn-tooltip {
  font-family: 'Georgia', serif !important;
  font-size: 0.82rem !important;
}
.fn-tooltip b {
  font-family: 'Palatino Linotype', Palatino, serif !important;
  font-size: 0.88rem !important;
}
.fn-tooltip-syn {
  font-family: 'Courier New', monospace !important;
  font-size: 0.76rem !important;
}

/* ── Math tools card results → Courier New ── */
.mt-result-line {
  font-family: 'Courier New', monospace !important;
  font-size: 0.96rem !important;
}

/* ── Brand sub-text → Trebuchet ── */
.brand-sub {
  font-family: 'Trebuchet MS', Arial, sans-serif !important;
  font-size: 0.78rem !important;
  letter-spacing: 2px !important;
}

/* ── Converter values → Courier New ── */
.conv-value,
.conv-result {
  font-family: 'Courier New', monospace !important;
  font-size: 1.1rem !important;
  font-weight: 700 !important;
}


/* ── π button above Calc ── */
.adv-calc-wrap {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 4px;
  flex-shrink: 0;
}
.pi-above {
  position: static !important;
  transform: none !important;
  width: 100%;
  padding: 3px 10px;
  font-size: 0.82rem;
  background: linear-gradient(135deg, rgba(0,212,255,0.18), rgba(168,85,247,0.18));
  border: 1px solid rgba(0,212,255,0.35);
  border-radius: 6px;
  color: #00d4ff;
  font-weight: 700;
  cursor: pointer;
  transition: all 0.15s;
  font-family: Georgia, serif;
  text-align: center;
}
.pi-above:hover {
  background: rgba(0,212,255,0.30);
  box-shadow: 0 0 8px rgba(0,212,255,0.35);
}

/* ── Remove old inline pi-insert-btn rules ── */
.adv-input { padding-right: 12px !important; }

/* ── Compact tooltip — smaller and tighter ── */
.fn-tooltip-wrap .fn-tooltip {
  padding: 8px 12px !important;
  font-size: 0.73rem !important;
  line-height: 1.45 !important;
  border-radius: 10px !important;
}
.fn-tooltip b {
  font-size: 0.78rem !important;
  margin-bottom: 2px !important;
}
.fn-tooltip-syn {
  margin-top: 5px !important;
  padding: 3px 7px !important;
  font-size: 0.68rem !important;
}