/* ===== Reset & Base ===== */
*, *::before, *::after {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

:root {
  --bg-primary: #0a0a0f;
  --bg-secondary: #1a1a2e;
  --card-bg: rgba(255, 255, 255, 0.05);
  --card-border: rgba(255, 255, 255, 0.08);
  --text-primary: #e8e8f0;
  --text-secondary: #8888a0;
  --text-muted: #555570;
  --accent-cyan: #00d4ff;
  --accent-purple: #7b2ff7;
  --gradient-accent: linear-gradient(135deg, #00d4ff, #7b2ff7);
  --gradient-accent-hover: linear-gradient(135deg, #33dfff, #9b5ff9);
  --strength-weak: #ff4444;
  --strength-fair: #ff8c00;
  --strength-good: #ffd700;
  --strength-strong: #44cc44;
  --strength-very: #00e676;
  --radius: 12px;
  --radius-sm: 8px;
  --transition: 0.2s ease;
  --font-mono: 'SF Mono', 'Fira Code', 'Cascadia Code', 'Consolas', monospace;
  --font-sans: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Noto Sans KR', sans-serif;
}

/* ===== Light Theme ===== */
[data-theme="light"] {
  --bg-primary: #f0f2f5;
  --bg-secondary: #ffffff;
  --card-bg: rgba(0, 0, 0, 0.03);
  --card-border: rgba(0, 0, 0, 0.1);
  --text-primary: #1a1a2e;
  --text-secondary: #555570;
  --text-muted: #8888a0;
  --strength-weak: #dc2626;
  --strength-fair: #ea580c;
  --strength-good: #ca8a04;
  --strength-strong: #16a34a;
  --strength-very: #059669;
}

html {
  font-size: 16px;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

body {
  font-family: var(--font-sans);
  background: linear-gradient(160deg, var(--bg-primary) 0%, var(--bg-secondary) 100%);
  color: var(--text-primary);
  min-height: 100vh;
  line-height: 1.5;
}

/* ===== App Container ===== */
.app-container {
  max-width: 520px;
  margin: 0 auto;
  padding: 0 16px;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

/* ===== Header ===== */
.app-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 20px 0 16px;
  border-bottom: 1px solid var(--card-border);
  margin-bottom: 24px;
}

.logo {
  display: flex;
  align-items: center;
  gap: 12px;
}

.logo h1 {
  font-size: 1.2rem;
  font-weight: 700;
  background: var(--gradient-accent);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

/* Header Actions */
.header-actions {
  display: flex;
  align-items: center;
  gap: 8px;
}

/* Theme Toggle */
.theme-toggle {
  background: var(--card-bg);
  border: 1px solid var(--card-border);
  color: var(--text-primary);
  padding: 7px;
  border-radius: 50%;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all var(--transition);
}

.theme-toggle:hover {
  border-color: var(--accent-cyan);
  box-shadow: 0 0 12px rgba(0, 212, 255, 0.2);
}

.theme-toggle .icon-moon {
  display: none;
}

[data-theme="light"] .theme-toggle .icon-sun {
  display: none;
}

[data-theme="light"] .theme-toggle .icon-moon {
  display: block;
}

.lang-toggle {
  background: var(--card-bg);
  border: 1px solid var(--card-border);
  color: var(--text-primary);
  padding: 6px 14px;
  border-radius: 20px;
  cursor: pointer;
  font-size: 0.8rem;
  font-weight: 600;
  letter-spacing: 0.5px;
  transition: all var(--transition);
}

.lang-toggle:hover {
  border-color: var(--accent-cyan);
  box-shadow: 0 0 12px rgba(0, 212, 255, 0.2);
}

/* ===== Mode Tabs ===== */
.mode-tabs {
  display: flex;
  gap: 4px;
  background: var(--card-bg);
  border-radius: var(--radius);
  padding: 4px;
  margin-bottom: 16px;
  border: 1px solid var(--card-border);
}

.mode-tab {
  flex: 1;
  padding: 10px 16px;
  border: none;
  background: transparent;
  color: var(--text-secondary);
  font-size: 0.9rem;
  font-weight: 500;
  cursor: pointer;
  border-radius: var(--radius-sm);
  transition: all var(--transition);
  font-family: var(--font-sans);
}

.mode-tab.active {
  background: var(--gradient-accent);
  color: #fff;
  font-weight: 600;
}

.mode-tab:not(.active):hover {
  color: var(--text-primary);
  background: rgba(255, 255, 255, 0.05);
}

/* ===== Password Display ===== */
.password-display-card {
  background: var(--card-bg);
  border: 1px solid var(--card-border);
  border-radius: var(--radius);
  padding: 16px 20px;
  display: flex;
  align-items: center;
  gap: 12px;
  margin-bottom: 8px;
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
}

.password-output {
  flex: 1;
  font-family: var(--font-mono);
  font-size: 1.05rem;
  word-break: break-all;
  line-height: 1.6;
  color: var(--text-primary);
  min-height: 28px;
  display: flex;
  align-items: center;
}

.placeholder-text {
  color: var(--text-muted);
  font-family: var(--font-sans);
  font-size: 0.9rem;
}

.copy-btn {
  background: none;
  border: 1px solid var(--card-border);
  color: var(--text-secondary);
  padding: 8px;
  border-radius: var(--radius-sm);
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all var(--transition);
  flex-shrink: 0;
}

.copy-btn:hover {
  color: var(--accent-cyan);
  border-color: var(--accent-cyan);
  box-shadow: 0 0 8px rgba(0, 212, 255, 0.2);
}

.copy-btn.copied {
  color: var(--strength-very);
  border-color: var(--strength-very);
}

/* QR Button */
.qr-btn {
  background: none;
  border: 1px solid var(--card-border);
  color: var(--text-secondary);
  padding: 8px;
  border-radius: var(--radius-sm);
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all var(--transition);
  flex-shrink: 0;
}

.qr-btn:hover {
  color: var(--accent-purple);
  border-color: var(--accent-purple);
  box-shadow: 0 0 8px rgba(123, 47, 247, 0.2);
}

/* QR Modal */
.qr-modal-overlay {
  position: fixed;
  inset: 0;
  background: rgba(0, 0, 0, 0.7);
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 2000;
  animation: fadeIn 0.2s ease;
}

.qr-modal-overlay.hidden {
  display: none !important;
}

.qr-modal {
  background: var(--bg-secondary);
  border: 1px solid var(--card-border);
  border-radius: var(--radius);
  padding: 24px;
  max-width: 320px;
  width: 90%;
  text-align: center;
}

.qr-modal-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 20px;
}

.qr-modal-header h3 {
  font-size: 1rem;
  font-weight: 600;
  color: var(--text-primary);
}

.qr-modal-close {
  background: none;
  border: none;
  color: var(--text-secondary);
  font-size: 1.5rem;
  cursor: pointer;
  line-height: 1;
  padding: 0 4px;
  transition: color var(--transition);
}

.qr-modal-close:hover {
  color: var(--text-primary);
}

.qr-modal-body {
  display: flex;
  justify-content: center;
  padding: 16px;
  background: #fff;
  border-radius: var(--radius-sm);
  margin-bottom: 12px;
}

.qr-modal-body img {
  display: block;
  width: 200px;
  height: 200px;
}

.qr-modal-hint {
  font-size: 0.8rem;
  color: var(--text-muted);
}

/* ===== Strength Meter ===== */
.strength-section {
  margin-bottom: 20px;
  padding: 0 4px;
}

.strength-bar {
  height: 4px;
  background: rgba(255, 255, 255, 0.08);
  border-radius: 2px;
  overflow: hidden;
  margin-bottom: 6px;
}

.strength-fill {
  height: 100%;
  width: 0%;
  border-radius: 2px;
  transition: width 0.4s ease, background 0.4s ease;
}

.strength-info {
  display: flex;
  justify-content: space-between;
  font-size: 0.78rem;
}

.strength-label {
  color: var(--text-secondary);
  font-weight: 500;
}

.entropy-label {
  color: var(--text-muted);
  font-family: var(--font-mono);
  font-size: 0.72rem;
}

/* ===== Settings Card ===== */
.settings-card {
  background: var(--card-bg);
  border: 1px solid var(--card-border);
  border-radius: var(--radius);
  padding: 20px;
  margin-bottom: 16px;
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
}

.settings-card.hidden {
  display: none;
}

.setting-group {
  margin-bottom: 20px;
}

.setting-group:last-child {
  margin-bottom: 0;
}

.setting-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 10px;
}

.setting-header label {
  font-size: 0.88rem;
  color: var(--text-secondary);
  font-weight: 500;
}

.setting-section-label {
  display: block;
  font-size: 0.88rem;
  color: var(--text-secondary);
  font-weight: 500;
  margin-bottom: 12px;
}

/* Number inputs */
.length-input,
.count-input {
  width: 64px;
  background: rgba(255, 255, 255, 0.08);
  border: 1px solid var(--card-border);
  color: var(--text-primary);
  padding: 6px 10px;
  border-radius: var(--radius-sm);
  font-size: 0.88rem;
  text-align: center;
  font-family: var(--font-mono);
  outline: none;
  transition: border-color var(--transition);
}

.length-input:focus,
.count-input:focus {
  border-color: var(--accent-cyan);
}

/* Range Slider */
.range-slider {
  -webkit-appearance: none;
  appearance: none;
  width: 100%;
  height: 6px;
  background: rgba(255, 255, 255, 0.08);
  border-radius: 3px;
  outline: none;
  cursor: pointer;
}

.range-slider::-webkit-slider-thumb {
  -webkit-appearance: none;
  width: 20px;
  height: 20px;
  border-radius: 50%;
  background: var(--gradient-accent);
  cursor: pointer;
  border: 2px solid #1a1a2e;
  box-shadow: 0 0 8px rgba(0, 212, 255, 0.3);
  transition: box-shadow var(--transition);
}

.range-slider::-webkit-slider-thumb:hover {
  box-shadow: 0 0 16px rgba(0, 212, 255, 0.5);
}

.range-slider::-moz-range-thumb {
  width: 20px;
  height: 20px;
  border-radius: 50%;
  background: var(--gradient-accent);
  cursor: pointer;
  border: 2px solid #1a1a2e;
  box-shadow: 0 0 8px rgba(0, 212, 255, 0.3);
}

/* Toggle Grid */
.toggle-grid {
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.toggle-item {
  display: flex;
  align-items: center;
  justify-content: space-between;
  cursor: pointer;
  padding: 8px 12px;
  background: rgba(255, 255, 255, 0.03);
  border-radius: var(--radius-sm);
  transition: background var(--transition);
}

.toggle-item:hover {
  background: rgba(255, 255, 255, 0.06);
}

.toggle-item span:first-child {
  font-size: 0.85rem;
  color: var(--text-primary);
}

.toggle-checkbox {
  display: none;
}

.toggle-switch {
  position: relative;
  width: 44px;
  height: 24px;
  background: rgba(255, 255, 255, 0.1);
  border-radius: 12px;
  flex-shrink: 0;
  transition: background var(--transition);
}

.toggle-switch::after {
  content: '';
  position: absolute;
  top: 3px;
  left: 3px;
  width: 18px;
  height: 18px;
  background: var(--text-secondary);
  border-radius: 50%;
  transition: all var(--transition);
}

.toggle-checkbox:checked + .toggle-switch {
  background: linear-gradient(135deg, #00d4ff, #7b2ff7);
}

.toggle-checkbox:checked + .toggle-switch::after {
  left: 23px;
  background: #fff;
}

/* Separator Options */
.separator-options {
  display: flex;
  gap: 8px;
}

.sep-btn {
  flex: 1;
  padding: 8px 12px;
  background: rgba(255, 255, 255, 0.05);
  border: 1px solid var(--card-border);
  color: var(--text-secondary);
  border-radius: var(--radius-sm);
  cursor: pointer;
  font-size: 0.9rem;
  font-family: var(--font-mono);
  transition: all var(--transition);
}

.sep-btn:hover {
  border-color: var(--accent-cyan);
  color: var(--text-primary);
}

.sep-btn.active {
  background: var(--gradient-accent);
  border-color: transparent;
  color: #fff;
  font-weight: 600;
}

/* ===== Generate Button ===== */
.generate-btn {
  width: 100%;
  padding: 14px 24px;
  background: var(--gradient-accent);
  border: none;
  border-radius: var(--radius);
  color: #fff;
  font-size: 1rem;
  font-weight: 600;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  margin-bottom: 16px;
  transition: all var(--transition);
  font-family: var(--font-sans);
  position: relative;
  overflow: hidden;
}

.generate-btn::before {
  content: '';
  position: absolute;
  inset: 0;
  background: var(--gradient-accent-hover);
  opacity: 0;
  transition: opacity var(--transition);
}

.generate-btn:hover::before {
  opacity: 1;
}

.generate-btn:hover {
  box-shadow: 0 0 24px rgba(0, 212, 255, 0.3), 0 0 48px rgba(123, 47, 247, 0.15);
  transform: translateY(-1px);
}

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

.generate-btn svg,
.generate-btn span {
  position: relative;
  z-index: 1;
}

/* ===== Results List ===== */
.results-list {
  display: flex;
  flex-direction: column;
  gap: 8px;
  margin-bottom: 20px;
}

.results-list.hidden {
  display: none;
}

.result-item {
  background: var(--card-bg);
  border: 1px solid var(--card-border);
  border-radius: var(--radius-sm);
  padding: 12px 16px;
  display: flex;
  align-items: center;
  gap: 12px;
  animation: fadeIn 0.3s ease;
}

.result-item .result-text {
  flex: 1;
  font-family: var(--font-mono);
  font-size: 0.88rem;
  word-break: break-all;
  line-height: 1.5;
}

.result-item .copy-btn {
  padding: 6px;
}

/* ===== History Section ===== */
.history-section {
  margin-top: 8px;
  padding-top: 20px;
  border-top: 1px solid var(--card-border);
}

.history-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 12px;
}

.history-header h2 {
  font-size: 1rem;
  font-weight: 600;
  color: var(--text-secondary);
}

.clear-history-btn {
  background: none;
  border: 1px solid rgba(255, 68, 68, 0.3);
  color: #ff6666;
  padding: 4px 12px;
  border-radius: var(--radius-sm);
  cursor: pointer;
  font-size: 0.75rem;
  transition: all var(--transition);
  font-family: var(--font-sans);
}

.clear-history-btn:hover {
  background: rgba(255, 68, 68, 0.1);
  border-color: rgba(255, 68, 68, 0.5);
}

.history-list {
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.history-empty {
  text-align: center;
  color: var(--text-muted);
  font-size: 0.85rem;
  padding: 24px 0;
}

.history-item {
  background: var(--card-bg);
  border: 1px solid var(--card-border);
  border-radius: var(--radius-sm);
  padding: 10px 14px;
  display: flex;
  align-items: center;
  gap: 10px;
  animation: fadeIn 0.3s ease;
}

.history-item .history-pw {
  flex: 1;
  font-family: var(--font-mono);
  font-size: 0.82rem;
  word-break: break-all;
  color: var(--text-primary);
  line-height: 1.4;
}

.history-item .history-meta {
  font-size: 0.7rem;
  color: var(--text-muted);
  white-space: nowrap;
  flex-shrink: 0;
}

.history-item .copy-btn {
  padding: 5px;
  flex-shrink: 0;
}

.history-item .copy-btn svg {
  width: 14px;
  height: 14px;
}

/* ===== Toast ===== */
.toast {
  position: fixed;
  bottom: 32px;
  left: 50%;
  transform: translateX(-50%) translateY(20px);
  background: rgba(0, 212, 255, 0.15);
  border: 1px solid rgba(0, 212, 255, 0.3);
  color: var(--accent-cyan);
  padding: 10px 24px;
  border-radius: var(--radius);
  font-size: 0.85rem;
  font-weight: 500;
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  opacity: 0;
  transition: all 0.3s ease;
  z-index: 1000;
  pointer-events: none;
}

.toast.show {
  opacity: 1;
  transform: translateX(-50%) translateY(0);
}

.toast.hidden {
  display: block;
}

/* ===== Footer ===== */
.app-footer {
  margin-top: auto;
  padding: 20px 0;
  text-align: center;
  color: var(--text-muted);
  font-size: 0.75rem;
  border-top: 1px solid var(--card-border);
}

/* ===== Animations ===== */
@keyframes fadeIn {
  from {
    opacity: 0;
    transform: translateY(8px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

/* ===== Hidden Utility ===== */
.hidden {
  display: none !important;
}

/* ===== Scrollbar ===== */
::-webkit-scrollbar {
  width: 6px;
}

::-webkit-scrollbar-track {
  background: transparent;
}

::-webkit-scrollbar-thumb {
  background: rgba(255, 255, 255, 0.1);
  border-radius: 3px;
}

::-webkit-scrollbar-thumb:hover {
  background: rgba(255, 255, 255, 0.2);
}

/* ===== Responsive ===== */
@media (max-width: 560px) {
  .app-container {
    padding: 0 12px;
  }

  .logo h1 {
    font-size: 1rem;
  }

  .password-output {
    font-size: 0.92rem;
  }

  .settings-card {
    padding: 16px;
  }

  .separator-options {
    flex-wrap: wrap;
  }

  .sep-btn {
    min-width: calc(50% - 4px);
  }
}

/* ===== Light Theme Overrides ===== */
[data-theme="light"] body {
  background: linear-gradient(160deg, var(--bg-primary) 0%, #e8eaf0 100%);
}

[data-theme="light"] .mode-tab:not(.active):hover {
  background: rgba(0, 0, 0, 0.05);
}

[data-theme="light"] .toggle-switch {
  background: rgba(0, 0, 0, 0.12);
}

[data-theme="light"] .toggle-switch::after {
  background: #999;
}

[data-theme="light"] .toggle-item {
  background: rgba(0, 0, 0, 0.02);
}

[data-theme="light"] .toggle-item:hover {
  background: rgba(0, 0, 0, 0.05);
}

[data-theme="light"] .length-input,
[data-theme="light"] .count-input {
  background: rgba(0, 0, 0, 0.05);
}

[data-theme="light"] .range-slider {
  background: rgba(0, 0, 0, 0.1);
}

[data-theme="light"] .range-slider::-webkit-slider-thumb {
  border-color: #fff;
  box-shadow: 0 1px 4px rgba(0, 0, 0, 0.2);
}

[data-theme="light"] .range-slider::-moz-range-thumb {
  border-color: #fff;
  box-shadow: 0 1px 4px rgba(0, 0, 0, 0.2);
}

[data-theme="light"] .sep-btn {
  background: rgba(0, 0, 0, 0.03);
}

[data-theme="light"] .strength-bar {
  background: rgba(0, 0, 0, 0.08);
}

[data-theme="light"] .toast {
  background: rgba(0, 212, 255, 0.1);
  border-color: rgba(0, 212, 255, 0.4);
}

[data-theme="light"] .qr-modal {
  background: #fff;
}

[data-theme="light"] .clear-history-btn {
  border-color: rgba(220, 38, 38, 0.3);
  color: #dc2626;
}

[data-theme="light"] .clear-history-btn:hover {
  background: rgba(220, 38, 38, 0.06);
  border-color: rgba(220, 38, 38, 0.5);
}

[data-theme="light"] ::-webkit-scrollbar-thumb {
  background: rgba(0, 0, 0, 0.1);
}

[data-theme="light"] ::-webkit-scrollbar-thumb:hover {
  background: rgba(0, 0, 0, 0.2);
}

/* ===== Selection ===== */
::selection {
  background: rgba(0, 212, 255, 0.3);
  color: #fff;
}