/* ============================================================
   OVERLAP — Glassmorphism Dark UI
   Palette: void navy base, cyan + pink neon accents, violet third tone
   ============================================================ */

:root {
  --void-950: #060912;
  --void-900: #0A0F1C;
  --void-800: #111729;
  --glass-fill: rgba(18, 24, 41, 0.55);
  --glass-border: rgba(255, 255, 255, 0.08);
  --glass-border-hi: rgba(255, 255, 255, 0.16);

  --cyan: #5FF7E0;
  --cyan-dim: #15C9E0;
  --pink: #FF8AD8;
  --pink-dim: #E0359A;
  --violet: #C6A8FF;

  --text-hi: #EAF2FF;
  --text-mid: #8C9AB8;
  --text-dim: #56607A;

  --radius-lg: 28px;
  --radius-md: 18px;
  --radius-sm: 12px;

  --ease-out: cubic-bezier(0.16, 1, 0.3, 1);
  --ease-spring: cubic-bezier(0.34, 1.56, 0.64, 1);
}

* { box-sizing: border-box; }

html, body {
  margin: 0;
  padding: 0;
  background: var(--void-950);
  color: var(--text-hi);
  font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  min-height: 100vh;
  overflow-x: hidden;
}

/* ============ AMBIENT BACKGROUND ============ */

.bg-grid {
  position: fixed;
  inset: 0;
  background-image:
    linear-gradient(rgba(255,255,255,0.025) 1px, transparent 1px),
    linear-gradient(90deg, rgba(255,255,255,0.025) 1px, transparent 1px);
  background-size: 48px 48px;
  mask-image: radial-gradient(ellipse 80% 60% at 50% 30%, black 0%, transparent 75%);
  z-index: 0;
  pointer-events: none;
}

.bg-glow {
  position: fixed;
  border-radius: 50%;
  filter: blur(120px);
  opacity: 0.35;
  z-index: 0;
  pointer-events: none;
  animation: drift 18s ease-in-out infinite alternate;
}

.bg-glow--cyan {
  width: 520px; height: 520px;
  background: var(--cyan-dim);
  top: -120px; left: -160px;
}

.bg-glow--pink {
  width: 480px; height: 480px;
  background: var(--pink-dim);
  bottom: -160px; right: -140px;
  animation-delay: -9s;
}

@keyframes drift {
  0%   { transform: translate(0, 0) scale(1); }
  100% { transform: translate(40px, -30px) scale(1.08); }
}

/* ============ SHELL & LAYOUT ============ */

.shell {
  position: relative;
  z-index: 1;
  max-width: 640px;
  margin: 0 auto;
  padding: 32px 20px 80px;
  display: flex;
  flex-direction: column;
  gap: 24px;
}

.topbar {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  padding: 4px 4px 8px;
}

.brand { display: flex; align-items: center; gap: 10px; }

.brand__mark {
  width: 10px; height: 10px;
  border-radius: 50%;
  background: var(--cyan);
  box-shadow: 0 0 12px 2px var(--cyan), 0 0 24px 6px rgba(95, 247, 224, 0.35);
}

.brand__text {
  font-weight: 700;
  font-size: 15px;
  letter-spacing: 0.12em;
  color: var(--text-hi);
}

.topbar__tag {
  font-size: 11px;
  letter-spacing: 0.08em;
  color: var(--text-dim);
  text-transform: uppercase;
}

/* ============ GLASS PANEL BASE ============ */

.panel--glass {
  background: var(--glass-fill);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-lg);
  backdrop-filter: blur(20px) saturate(140%);
  -webkit-backdrop-filter: blur(20px) saturate(140%);
  box-shadow:
    0 1px 0 0 rgba(255,255,255,0.06) inset,
    0 24px 60px -20px rgba(0,0,0,0.6);
  padding: 32px;
  animation: panelIn 0.6s var(--ease-out) both;
}

@keyframes panelIn {
  from { opacity: 0; transform: translateY(14px) scale(0.985); }
  to   { opacity: 1; transform: translateY(0) scale(1); }
}

.panel__title {
  font-size: 26px;
  font-weight: 700;
  letter-spacing: -0.01em;
  margin: 0 0 8px;
  background: linear-gradient(120deg, var(--text-hi) 30%, var(--cyan) 100%);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}

.panel__sub {
  font-size: 14px;
  color: var(--text-mid);
  line-height: 1.55;
  margin: 0 0 28px;
  max-width: 460px;
}

/* ============ HANDLE INPUTS ============ */

.handle-grid {
  display: flex;
  flex-direction: column;
  gap: 12px;
  margin-bottom: 14px;
}

.handle-field {
  position: relative;
  display: flex;
  align-items: center;
  background: rgba(255,255,255,0.03);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-md);
  padding: 0 14px;
  transition: border-color 0.25s var(--ease-out), background 0.25s var(--ease-out);
}

.handle-field:focus-within {
  border-color: var(--cyan-dim);
  background: rgba(95, 247, 224, 0.04);
  box-shadow: 0 0 0 3px rgba(95, 247, 224, 0.08);
}

.handle-field--optional {
  display: none;
  animation: slideIn 0.35s var(--ease-spring) both;
}

.handle-field--optional.is-visible { display: flex; }

@keyframes slideIn {
  from { opacity: 0; transform: translateY(-8px); }
  to   { opacity: 1; transform: translateY(0); }
}

.handle-field__prefix {
  color: var(--text-dim);
  font-size: 15px;
  font-weight: 600;
  padding-right: 2px;
}

.handle-field__input {
  flex: 1;
  background: transparent;
  border: none;
  outline: none;
  color: var(--text-hi);
  font-size: 15px;
  font-family: inherit;
  padding: 14px 8px;
}

.handle-field__input::placeholder { color: var(--text-dim); }

.handle-field__chip {
  font-size: 10px;
  font-weight: 700;
  letter-spacing: 0.04em;
  color: var(--void-950);
  background: var(--text-dim);
  border-radius: 6px;
  padding: 3px 7px;
  opacity: 0.7;
}

.handle-field:nth-child(1) .handle-field__chip { background: var(--cyan); }
.handle-field:nth-child(2) .handle-field__chip { background: var(--pink); }
.handle-field--optional .handle-field__chip { background: var(--violet); }

.btn-add-handle {
  background: none;
  border: none;
  color: var(--cyan-dim);
  font-size: 13px;
  font-weight: 600;
  cursor: pointer;
  padding: 4px 0 24px;
  text-align: left;
  transition: color 0.2s;
}

.btn-add-handle:hover { color: var(--cyan); }
.btn-add-handle.is-hidden { display: none; }

/* ============ PRIMARY BUTTON ============ */

.btn-analyze {
  position: relative;
  width: 100%;
  border: none;
  border-radius: var(--radius-md);
  padding: 17px 24px;
  font-size: 15px;
  font-weight: 700;
  letter-spacing: 0.01em;
  color: var(--void-950);
  background: linear-gradient(110deg, var(--cyan) 0%, var(--cyan-dim) 50%, var(--pink) 130%);
  cursor: pointer;
  overflow: hidden;
  transition: transform 0.2s var(--ease-out), box-shadow 0.3s var(--ease-out);
  box-shadow: 0 8px 28px -8px rgba(95, 247, 224, 0.45);
}

.btn-analyze:hover { transform: translateY(-1px); box-shadow: 0 12px 32px -8px rgba(95, 247, 224, 0.6); }
.btn-analyze:active { transform: translateY(0px) scale(0.99); }

.btn-analyze:disabled {
  opacity: 0.6;
  cursor: not-allowed;
  transform: none;
}

.btn-analyze__spinner {
  display: none;
  position: absolute;
  right: 22px;
  top: 50%;
  width: 16px; height: 16px;
  margin-top: -8px;
  border-radius: 50%;
  border: 2px solid rgba(6,9,18,0.25);
  border-top-color: var(--void-950);
  animation: spin 0.7s linear infinite;
}

.btn-analyze.is-loading .btn-analyze__spinner { display: block; }
.btn-analyze.is-loading .btn-analyze__label { opacity: 0.7; }

@keyframes spin { to { transform: rotate(360deg); } }

.panel__error {
  color: var(--pink);
  font-size: 13px;
  margin: 14px 0 0;
  min-height: 16px;
  opacity: 0;
  transition: opacity 0.2s;
}

.panel__error.is-visible { opacity: 1; }

/* ============ LOADING PANEL ============ */

.panel--loading {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 20px;
  padding: 48px 32px;
}

.pulse-ring {
  width: 64px; height: 64px;
  border-radius: 50%;
  border: 2px solid var(--cyan-dim);
  position: relative;
}

.pulse-ring::before, .pulse-ring::after {
  content: '';
  position: absolute;
  inset: 0;
  border-radius: 50%;
  border: 2px solid var(--cyan);
  animation: pulse 1.8s var(--ease-out) infinite;
}

.pulse-ring::after { animation-delay: 0.6s; }

@keyframes pulse {
  0%   { transform: scale(0.6); opacity: 1; }
  100% { transform: scale(1.8); opacity: 0; }
}

.loading__status {
  font-size: 14px;
  color: var(--text-mid);
  margin: 0;
  letter-spacing: 0.01em;
}

.loading__steps {
  display: flex;
  gap: 18px;
}

.step {
  font-size: 11px;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--text-dim);
  position: relative;
  padding-left: 14px;
}

.step::before {
  content: '';
  position: absolute;
  left: 0; top: 50%;
  width: 6px; height: 6px;
  margin-top: -3px;
  border-radius: 50%;
  background: var(--text-dim);
  transition: background 0.3s, box-shadow 0.3s;
}

.step.is-active { color: var(--cyan); }
.step.is-active::before { background: var(--cyan); box-shadow: 0 0 8px 2px rgba(95,247,224,0.6); }
.step.is-done { color: var(--text-mid); }
.step.is-done::before { background: var(--pink); }

/* ============ RESULTS PANEL ============ */

.panel--results { padding: 32px 28px; }

.results__source {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-size: 11px;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--text-dim);
  margin-bottom: 18px;
}

.results__source::before {
  content: '';
  width: 6px; height: 6px;
  border-radius: 50%;
  background: var(--cyan);
}

.results__source.is-cached::before { background: var(--violet); }

.venn-wrap {
  display: flex;
  justify-content: center;
  margin: 4px 0 28px;
}

.venn { width: 100%; max-width: 360px; height: auto; }

.venn-circle {
  transition: r 0.7s var(--ease-spring), cx 0.7s var(--ease-spring), cy 0.7s var(--ease-spring), opacity 0.5s ease;
  mix-blend-mode: screen;
}

.venn-label {
  font-size: 11px;
  font-weight: 600;
  fill: var(--text-hi);
  text-anchor: middle;
  opacity: 0;
  animation: fadeUp 0.5s var(--ease-out) both;
}

@keyframes fadeUp {
  from { opacity: 0; transform: translateY(4px); }
  to   { opacity: 1; transform: translateY(0); }
}

.stat-row {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 10px;
  margin-bottom: 22px;
}

.stat-card {
  background: rgba(255,255,255,0.03);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-sm);
  padding: 16px 10px;
  text-align: center;
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.stat-card--accent {
  border-color: rgba(255, 138, 216, 0.3);
  background: rgba(255, 138, 216, 0.06);
}

.stat-card__value {
  font-size: 22px;
  font-weight: 700;
  color: var(--text-hi);
  font-variant-numeric: tabular-nums;
}

.stat-card--accent .stat-card__value { color: var(--pink); }

.stat-card__label {
  font-size: 10.5px;
  color: var(--text-mid);
  letter-spacing: 0.02em;
  line-height: 1.3;
}

.pair-breakdown {
  display: flex;
  flex-direction: column;
  gap: 8px;
  margin-bottom: 24px;
}

.pair-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-size: 13px;
  padding: 10px 14px;
  border-radius: 10px;
  background: rgba(255,255,255,0.025);
  border: 1px solid var(--glass-border);
}

.pair-row__handles { color: var(--text-mid); }
.pair-row__handles b { color: var(--text-hi); font-weight: 600; }
.pair-row__value { color: var(--cyan); font-weight: 700; font-variant-numeric: tabular-nums; }

.btn-secondary {
  width: 100%;
  background: rgba(255,255,255,0.04);
  border: 1px solid var(--glass-border-hi);
  border-radius: var(--radius-md);
  color: var(--text-mid);
  font-size: 13px;
  font-weight: 600;
  padding: 13px;
  cursor: pointer;
  transition: color 0.2s, border-color 0.2s, background 0.2s;
}

.btn-secondary:hover {
  color: var(--text-hi);
  border-color: var(--cyan-dim);
  background: rgba(95, 247, 224, 0.05);
}

/* ============ RESPONSIVE ============ */

@media (max-width: 480px) {
  .panel--glass { padding: 24px 20px; }
  .panel__title { font-size: 22px; }
  .stat-card__value { font-size: 18px; }
}

/* ============ ACCESSIBILITY ============ */

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }
}

.handle-field__input:focus-visible,
.btn-analyze:focus-visible,
.btn-secondary:focus-visible,
.btn-add-handle:focus-visible {
  outline: 2px solid var(--cyan);
  outline-offset: 2px;
}