:root {
  --bg: #0a0a0f;
  --surface: #111118;
  --card: #16161f;
  --border: #2a2a38;
  --accent: #e8ff47;
  --accent2: #7b5cff;
  --text: #f0f0f5;
  --muted: #6b6b80;
  --danger: #ff4f6e;
  --success: #47ffa0;
  --mono: 'Space Mono', monospace;
  --sans: 'Syne', sans-serif;
}

*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

body {
  background: var(--bg);
  color: var(--text);
  font-family: var(--sans);
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 24px;
  overflow-x: hidden;
}

body::before {
  content: '';
  position: fixed;
  inset: 0;
  background-image:
    linear-gradient(rgba(123,92,255,0.04) 1px, transparent 1px),
    linear-gradient(90deg, rgba(123,92,255,0.04) 1px, transparent 1px);
  background-size: 48px 48px;
  pointer-events: none;
  z-index: 0;
}

body::after {
  content: '';
  position: fixed;
  width: 600px;
  height: 600px;
  border-radius: 50%;
  background: radial-gradient(circle, rgba(123,92,255,0.12) 0%, transparent 70%);
  top: -200px;
  right: -200px;
  pointer-events: none;
  z-index: 0;
}

.container {
  position: relative;
  z-index: 1;
  width: 100%;
  max-width: 520px;
}

header {
  margin-bottom: 32px;
  text-align: left;
}

.logo-tag {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-family: var(--mono);
  font-size: 11px;
  color: var(--accent);
  text-transform: uppercase;
  letter-spacing: 0.15em;
  margin-bottom: 12px;
  opacity: 0;
  animation: fadeUp 0.5s ease forwards;
}

.logo-tag::before {
  content: '';
  width: 20px;
  height: 1px;
  background: var(--accent);
}

h1 {
  font-size: clamp(36px, 7vw, 52px);
  font-weight: 800;
  line-height: 1;
  letter-spacing: -0.03em;
  opacity: 0;
  animation: fadeUp 0.5s 0.1s ease forwards;
}

h1 span {
  color: var(--accent);
}

.subtitle {
  margin-top: 8px;
  color: var(--muted);
  font-size: 14px;
  font-weight: 400;
  opacity: 0;
  animation: fadeUp 0.5s 0.2s ease forwards;
}

.card {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 20px;
  padding: 28px;
  position: relative;
  overflow: hidden;
  opacity: 0;
  animation: fadeUp 0.5s 0.3s ease forwards;
}

.card::before {
  content: '';
  position: absolute;
  top: 0; left: 0; right: 0;
  height: 1px;
  background: linear-gradient(90deg, transparent, var(--accent2), transparent);
  opacity: 0.6;
}

.password-display {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 20px 18px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  margin-bottom: 24px;
  min-height: 72px;
  position: relative;
  overflow: hidden;
  transition: border-color 0.2s;
}

.password-display:hover {
  border-color: var(--accent2);
}

.password-display.copied {
  border-color: var(--success);
  animation: flashSuccess 0.4s ease;
}

.password-text {
  font-family: var(--mono);
  font-size: clamp(13px, 3vw, 17px);
  color: var(--text);
  word-break: break-all;
  line-height: 1.5;
  flex: 1;
  letter-spacing: 0.05em;
  transition: opacity 0.15s;
}

.password-text.flash {
  animation: scramble 0.3s ease;
}

.password-placeholder {
  color: var(--muted);
  font-family: var(--mono);
  font-size: 14px;
}

.copy-btn {
  background: transparent;
  border: 1px solid var(--border);
  border-radius: 8px;
  width: 40px;
  height: 40px;
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  color: var(--muted);
  flex-shrink: 0;
  transition: all 0.2s;
}

.copy-btn:hover {
  border-color: var(--accent);
  color: var(--accent);
  background: rgba(232,255,71,0.05);
}

.copy-btn.active {
  color: var(--success);
  border-color: var(--success);
}

.strength-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 20px;
  font-size: 12px;
  font-family: var(--mono);
  color: var(--muted);
}

.strength-bars {
  display: flex;
  gap: 4px;
}

.strength-bar {
  width: 32px;
  height: 4px;
  border-radius: 4px;
  background: var(--border);
  transition: background 0.3s;
}

.strength-label {
  letter-spacing: 0.1em;
  text-transform: uppercase;
}

.s1 .strength-bar:nth-child(1) { background: var(--danger); }

.s2 .strength-bar:nth-child(1),
.s2 .strength-bar:nth-child(2) { background: #ff9f47; }

.s3 .strength-bar:nth-child(1),
.s3 .strength-bar:nth-child(2),
.s3 .strength-bar:nth-child(3) { background: var(--accent); }

.s4 .strength-bar { background: var(--success); }

.s1 .strength-label { color: var(--danger); }
.s2 .strength-label { color: #ff9f47; }
.s3 .strength-label { color: var(--accent); }
.s4 .strength-label { color: var(--success); }

.section-label {
  font-size: 12px;
  font-family: var(--mono);
  color: var(--muted);
  text-transform: uppercase;
  letter-spacing: 0.12em;
  margin-bottom: 10px;
}

.length-row {
  display: flex;
  align-items: center;
  gap: 14px;
  margin-bottom: 22px;
}

.length-value {
  font-family: var(--mono);
  font-size: 22px;
  font-weight: 700;
  color: var(--accent);
  min-width: 36px;
  text-align: right;
}

input[type="range"] {
  -webkit-appearance: none;
  flex: 1;
  height: 4px;
  border-radius: 4px;
  background: var(--border);
  outline: none;
  cursor: pointer;
}

input[type="range"]::-webkit-slider-thumb {
  -webkit-appearance: none;
  width: 18px;
  height: 18px;
  border-radius: 50%;
  background: var(--accent);
  box-shadow: 0 0 0 4px rgba(232,255,71,0.15);
  transition: box-shadow 0.2s;
  cursor: pointer;
}

input[type="range"]::-webkit-slider-thumb:hover {
  box-shadow: 0 0 0 7px rgba(232,255,71,0.2);
}

.options-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 10px;
  margin-bottom: 24px;
}

.toggle-option {
  display: flex;
  align-items: center;
  justify-content: space-between;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 12px 14px;
  cursor: pointer;
  transition: all 0.2s;
  user-select: none;
}

.toggle-option:hover {
  border-color: var(--accent2);
}

.toggle-option.active {
  border-color: var(--accent);
  background: rgba(232,255,71,0.04);
}

.toggle-label {
  font-size: 13px;
  font-weight: 600;
  color: var(--text);
}

.toggle-sub {
  font-size: 10px;
  font-family: var(--mono);
  color: var(--muted);
  margin-top: 2px;
}

.toggle-switch {
  width: 34px;
  height: 20px;
  border-radius: 20px;
  background: var(--border);
  position: relative;
  flex-shrink: 0;
  transition: background 0.2s;
}

.toggle-switch::after {
  content: '';
  position: absolute;
  width: 14px;
  height: 14px;
  border-radius: 50%;
  background: var(--muted);
  top: 3px;
  left: 3px;
  transition: all 0.2s;
}

.toggle-option.active .toggle-switch {
  background: var(--accent);
}

.toggle-option.active .toggle-switch::after {
  background: var(--bg);
  left: 17px;
}

.generate-btn {
  width: 100%;
  padding: 16px;
  border: none;
  border-radius: 12px;
  font-family: var(--sans);
  font-size: 15px;
  font-weight: 800;
  letter-spacing: 0.05em;
  text-transform: uppercase;
  cursor: pointer;
  position: relative;
  overflow: hidden;
  background: var(--accent);
  color: var(--bg);
  transition: all 0.2s;
}

.generate-btn::before {
  content: '';
  position: absolute;
  inset: 0;
  background: linear-gradient(90deg, transparent 0%, rgba(255,255,255,0.25) 50%, transparent 100%);
  transform: translateX(-100%);
  transition: transform 0.4s ease;
}

.generate-btn:hover::before {
  transform: translateX(100%);
}

.generate-btn:hover {
  transform: translateY(-1px);
  box-shadow: 0 8px 30px rgba(232,255,71,0.25);
}

.generate-btn:active {
  transform: translateY(0);
}

.btn-icon {
  margin-right: 8px;
}

.card-footer {
  margin-top: 18px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-family: var(--mono);
  font-size: 11px;
  color: var(--muted);
  opacity: 0;
  animation: fadeUp 0.5s 0.4s ease forwards;
}

#entropyDisplay span {
  color: var(--accent2);
}

@keyframes fadeUp {
  from { opacity: 0; transform: translateY(12px); }
  to   { opacity: 1; transform: translateY(0); }
}

@keyframes scramble {
  0%   { opacity: 0.3; transform: translateY(2px); }
  100% { opacity: 1;   transform: translateY(0); }
}

@keyframes flashSuccess {
  0%   { background: var(--surface); }
  40%  { background: rgba(71,255,160,0.08); }
  100% { background: var(--surface); }
}

@media (max-width: 420px) {
  .options-grid {
    grid-template-columns: 1fr;
  }
}