/* ===================================================
   BASE64 · fruitpunch.dev — Design System
   =================================================== */

/* ── Fonts ── */
@import url('https://fonts.googleapis.com/css2?family=Inter:wght@300;400;500;600;700&family=JetBrains+Mono:wght@400;500&display=swap');

/* ── Design Tokens (Dark mode default) ── */
:root {
  --bg-base:         #0d0d14;
  --bg-surface:      #13131e;
  --bg-elevated:     #1a1a2a;
  --bg-overlay:      #20203a;
  --bg-hover:        #252540;
  --border:          #2a2a4a;
  --border-subtle:   #1e1e34;
  --border-focus:    #7c5cfc;

  --text-primary:    #f0f0ff;
  --text-secondary:  #9090c0;
  --text-muted:      #5a5a80;
  --text-disabled:   #3a3a60;

  --accent-main:     #7c5cfc;
  --accent-glow:     rgba(124, 92, 252, 0.3);
  --accent-hover:    #8f72fd;
  --accent-active:   #6a4ae0;

  --accent-2:        #fc5c8f;
  --accent-2-glow:   rgba(252, 92, 143, 0.25);

  --success:         #3dd68c;
  --success-glow:    rgba(61, 214, 140, 0.2);
  --warn:            #f7c948;
  --warn-glow:       rgba(247, 201, 72, 0.2);
  --error:           #ff6b6b;
  --error-glow:      rgba(255, 107, 107, 0.2);

  --font-sans:       'Inter', system-ui, -apple-system, sans-serif;
  --font-mono:       'JetBrains Mono', 'Fira Code', monospace;

  --radius-sm:       6px;
  --radius-md:       10px;
  --radius-lg:       16px;
  --radius-xl:       22px;

  --shadow-sm:       0 1px 3px rgba(0,0,0,0.4);
  --shadow-md:       0 4px 16px rgba(0,0,0,0.5);
  --shadow-lg:       0 8px 32px rgba(0,0,0,0.6);
  --shadow-glow:     0 0 30px var(--accent-glow);

  --transition:      180ms cubic-bezier(0.4, 0, 0.2, 1);
  --transition-slow: 320ms cubic-bezier(0.4, 0, 0.2, 1);

  --header-h:        60px;
  --panel-width:     380px;
}

/* ── Light Mode ── */
[data-theme="light"] {
  --bg-base:         #f4f4fb;
  --bg-surface:      #ffffff;
  --bg-elevated:     #ebebf8;
  --bg-overlay:      #dcdcf0;
  --bg-hover:        #e0e0f4;
  --border:          #d0d0e8;
  --border-subtle:   #e8e8f4;
  --border-focus:    #7c5cfc;

  --text-primary:    #0f0f24;
  --text-secondary:  #555580;
  --text-muted:      #8888b0;
  --text-disabled:   #bbbbd8;

  --shadow-sm:       0 1px 3px rgba(0,0,0,0.08);
  --shadow-md:       0 4px 16px rgba(0,0,0,0.1);
  --shadow-lg:       0 8px 32px rgba(0,0,0,0.14);
}

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

html {
  font-size: 15px;
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
}

body {
  font-family: var(--font-sans);
  background: var(--bg-base);
  color: var(--text-primary);
  min-height: 100vh;
  line-height: 1.6;
  overflow-x: hidden;
  transition: background var(--transition-slow), color var(--transition-slow);
}

/* Subtle background gradient mesh */
body::before {
  content: '';
  position: fixed;
  inset: 0;
  background:
    radial-gradient(ellipse 60% 40% at 20% -10%, rgba(124,92,252,0.12) 0%, transparent 70%),
    radial-gradient(ellipse 50% 35% at 80% 110%, rgba(252,92,143,0.08) 0%, transparent 70%);
  pointer-events: none;
  z-index: 0;
}

/* ── Utility ── */
.hidden { display: none !important; }
.visually-hidden {
  position: absolute;
  width: 1px; height: 1px;
  padding: 0; margin: -1px;
  overflow: hidden;
  clip: rect(0,0,0,0);
  white-space: nowrap;
  border: 0;
}

/* ── Header ── */
.app-header {
  position: sticky;
  top: 0;
  z-index: 100;
  height: var(--header-h);
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 24px;
  background: rgba(13,13,20,0.8);
  backdrop-filter: blur(16px) saturate(180%);
  -webkit-backdrop-filter: blur(16px) saturate(180%);
  border-bottom: 1px solid var(--border-subtle);
  transition: background var(--transition-slow);
}

[data-theme="light"] .app-header {
  background: rgba(244,244,251,0.85);
}

.header-nav {
  display: flex;
  align-items: center;
  gap: 2px;
  font-size: 1.1rem;
  font-weight: 600;
  letter-spacing: -0.01em;
}

.header-brand {
  color: var(--accent-main);
  text-decoration: none;
  font-weight: 700;
  transition: color var(--transition), text-shadow var(--transition);
}
.header-brand:hover {
  color: var(--accent-hover);
  text-shadow: 0 0 20px var(--accent-glow);
}

.header-dot { color: var(--text-muted); }

.header-domain {
  color: var(--text-secondary);
  text-decoration: none;
  transition: color var(--transition);
}
.header-domain:hover { color: var(--text-primary); }

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

/* ── Buttons ── */
.btn-icon {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 36px; height: 36px;
  border: none;
  background: transparent;
  color: var(--text-secondary);
  cursor: pointer;
  border-radius: var(--radius-sm);
  transition: background var(--transition), color var(--transition);
}
.btn-icon:hover { background: var(--bg-elevated); color: var(--text-primary); }
.btn-icon:focus-visible { outline: 2px solid var(--border-focus); outline-offset: 2px; }

.btn-advanced {
  display: flex;
  align-items: center;
  gap: 6px;
  padding: 7px 14px;
  border: 1px solid var(--border);
  background: var(--bg-elevated);
  color: var(--text-secondary);
  font-size: 0.82rem;
  font-weight: 500;
  font-family: var(--font-sans);
  border-radius: var(--radius-md);
  cursor: pointer;
  transition: all var(--transition);
}
.btn-advanced:hover {
  border-color: var(--accent-main);
  color: var(--accent-main);
  background: var(--accent-glow);
}
.btn-advanced[aria-expanded="true"] {
  background: var(--accent-glow);
  border-color: var(--accent-main);
  color: var(--accent-main);
}
.btn-advanced:focus-visible { outline: 2px solid var(--border-focus); outline-offset: 2px; }

.btn-primary {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 9px 20px;
  background: linear-gradient(135deg, var(--accent-main) 0%, var(--accent-hover) 100%);
  color: #fff;
  border: none;
  border-radius: var(--radius-md);
  font-size: 0.88rem;
  font-weight: 600;
  font-family: var(--font-sans);
  cursor: pointer;
  transition: all var(--transition);
  box-shadow: 0 4px 14px var(--accent-glow);
}
.btn-primary:hover {
  transform: translateY(-1px);
  box-shadow: 0 6px 20px var(--accent-glow);
}
.btn-primary:active { transform: translateY(0); }
.btn-primary:focus-visible { outline: 2px solid var(--border-focus); outline-offset: 2px; }

.btn-secondary {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 9px 20px;
  background: var(--bg-elevated);
  color: var(--text-primary);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  font-size: 0.88rem;
  font-weight: 500;
  font-family: var(--font-sans);
  cursor: pointer;
  transition: all var(--transition);
}
.btn-secondary:hover {
  border-color: var(--accent-main);
  color: var(--accent-main);
  background: var(--accent-glow);
}
.btn-secondary:focus-visible { outline: 2px solid var(--border-focus); outline-offset: 2px; }

.btn-sm {
  display: inline-flex;
  align-items: center;
  gap: 5px;
  padding: 5px 12px;
  background: var(--bg-elevated);
  color: var(--text-secondary);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  font-size: 0.78rem;
  font-weight: 500;
  font-family: var(--font-sans);
  cursor: pointer;
  transition: all var(--transition);
  white-space: nowrap;
}
.btn-sm:hover { border-color: var(--accent-main); color: var(--accent-main); background: var(--accent-glow); }
.btn-sm:disabled { opacity: 0.4; pointer-events: none; }
.btn-sm.danger:hover { border-color: var(--error); color: var(--error); background: var(--error-glow); }
.btn-sm:focus-visible { outline: 2px solid var(--border-focus); outline-offset: 2px; }

.btn-icon-sm {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 28px; height: 28px;
  border: none;
  background: transparent;
  color: var(--text-muted);
  cursor: pointer;
  border-radius: var(--radius-sm);
  transition: all var(--transition);
  flex-shrink: 0;
}
.btn-icon-sm:hover { background: var(--error-glow); color: var(--error); }
.btn-icon-sm:focus-visible { outline: 2px solid var(--border-focus); outline-offset: 2px; }

.btn-swap {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 40px; height: 40px;
  border: 1px solid var(--border);
  background: var(--bg-elevated);
  color: var(--text-secondary);
  border-radius: 50%;
  cursor: pointer;
  transition: all var(--transition);
}
.btn-swap:hover {
  border-color: var(--accent-main);
  color: var(--accent-main);
  background: var(--accent-glow);
  transform: rotate(180deg);
}
.btn-swap:focus-visible { outline: 2px solid var(--border-focus); outline-offset: 2px; }

.btn-danger {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 9px 18px;
  background: transparent;
  color: var(--error);
  border: 1px solid var(--error);
  border-radius: var(--radius-md);
  font-size: 0.85rem;
  font-weight: 600;
  font-family: var(--font-sans);
  cursor: pointer;
  transition: all var(--transition);
}
.btn-danger:hover { background: var(--error-glow); }
.btn-danger:focus-visible { outline: 2px solid var(--error); outline-offset: 2px; }

/* ── Main Layout ── */
.app-main {
  position: relative;
  z-index: 1;
  max-width: 1120px;
  margin: 0 auto;
  padding: 32px 24px 80px;
}

/* ── Hero ── */
.hero {
  text-align: center;
  margin-bottom: 36px;
}

.hero-title {
  font-size: clamp(1.8rem, 4vw, 2.8rem);
  font-weight: 700;
  letter-spacing: -0.03em;
  line-height: 1.15;
  margin-bottom: 12px;
  color: var(--text-primary);
}

.hero-highlight {
  background: linear-gradient(135deg, var(--accent-main), var(--accent-2));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.hero-sub {
  font-size: 1rem;
  color: var(--text-secondary);
  margin-bottom: 28px;
  max-width: 480px;
  margin-left: auto;
  margin-right: auto;
}

/* ── Mode Tabs ── */
.mode-tabs {
  display: inline-flex;
  background: var(--bg-surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-xl);
  padding: 4px;
  gap: 2px;
}

.mode-tab {
  padding: 8px 24px;
  border: none;
  background: transparent;
  color: var(--text-secondary);
  font-size: 0.88rem;
  font-weight: 500;
  font-family: var(--font-sans);
  cursor: pointer;
  border-radius: calc(var(--radius-xl) - 4px);
  transition: all var(--transition);
  white-space: nowrap;
}
.mode-tab:hover { color: var(--text-primary); background: var(--bg-elevated); }
.mode-tab.active {
  background: linear-gradient(135deg, var(--accent-main), var(--accent-hover));
  color: #fff;
  box-shadow: 0 2px 10px var(--accent-glow);
}
.mode-tab:focus-visible { outline: 2px solid var(--border-focus); outline-offset: 2px; }

/* ── Panel ── */
.panel { animation: fadeIn 0.2s ease; }

@keyframes fadeIn {
  from { opacity: 0; transform: translateY(6px); }
  to   { opacity: 1; transform: translateY(0); }
}

/* ── Dual Pane ── */
.dual-pane {
  display: grid;
  grid-template-columns: 1fr 48px 1fr;
  gap: 0;
  align-items: start;
}

.swap-col {
  display: flex;
  align-items: center;
  justify-content: center;
  padding-top: 48px;
}

.pane {
  background: var(--bg-surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  overflow: hidden;
  transition: border-color var(--transition), box-shadow var(--transition);
}
.pane:focus-within {
  border-color: var(--border-focus);
  box-shadow: 0 0 0 3px var(--accent-glow), var(--shadow-md);
}

.pane-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 12px 16px;
  border-bottom: 1px solid var(--border-subtle);
  background: var(--bg-elevated);
}

.pane-label {
  font-size: 0.78rem;
  font-weight: 600;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.08em;
}

.pane-actions {
  display: flex;
  align-items: center;
  gap: 6px;
  flex-wrap: wrap;
}

.pane-textarea {
  width: 100%;
  min-height: 220px;
  padding: 16px;
  background: transparent;
  color: var(--text-primary);
  border: none;
  resize: vertical;
  font-family: var(--font-mono);
  font-size: 0.88rem;
  line-height: 1.7;
  outline: none;
  transition: color var(--transition);
}
.pane-textarea::placeholder { color: var(--text-muted); }
.pane-textarea.output-area {
  background: var(--bg-base);
  color: var(--text-secondary);
}
.pane-textarea.output-area:not(:placeholder-shown) { color: var(--text-primary); }

.pane-footer {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 10px 16px;
  border-top: 1px solid var(--border-subtle);
  background: var(--bg-elevated);
  flex-wrap: wrap;
  gap: 8px;
}

.operation-btns {
  display: flex;
  gap: 8px;
}

.char-count {
  font-size: 0.75rem;
  color: var(--text-muted);
  font-family: var(--font-mono);
}

.status-badge {
  font-size: 0.75rem;
  font-weight: 600;
  padding: 2px 8px;
  border-radius: 99px;
  display: none;
}
.status-badge.success { display: inline-block; background: var(--success-glow); color: var(--success); border: 1px solid rgba(61,214,140,0.3); }
.status-badge.error   { display: inline-block; background: var(--error-glow); color: var(--error); border: 1px solid rgba(255,107,107,0.3); }
.status-badge.info    { display: inline-block; background: var(--accent-glow); color: var(--accent-main); border: 1px solid rgba(124,92,252,0.3); }

/* Two-column file panel */
.file-two-col {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(0, 1fr);
  gap: 24px;
}
@media (max-width: 768px) {
  .file-two-col {
    grid-template-columns: 1fr;
    gap: 20px;
  }
}

.file-section-card {
  background: var(--bg-surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-xl);
  padding: 24px;
  display: flex;
  flex-direction: column;
  gap: 20px;
}

.file-section-header {
  display: flex;
  align-items: center;
  gap: 12px;
}

.file-section-badge {
  font-size: 0.75rem;
  font-weight: 700;
  letter-spacing: 0.05em;
  text-transform: uppercase;
  border-radius: 6px;
  padding: 4px 10px;
}
.encode-badge {
  background: rgba(124, 92, 252, 0.15);
  color: var(--accent-main);
  border: 1px solid rgba(124, 92, 252, 0.3);
}
.decode-badge {
  background: rgba(61, 214, 140, 0.15);
  color: var(--success);
  border: 1px solid rgba(61, 214, 140, 0.3);
}

.file-section-desc {
  font-size: 0.85rem;
  color: var(--text-muted);
}

.file-drop-zone {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 10px;
  padding: 64px 32px;
  border: 2px dashed var(--border);
  border-radius: var(--radius-xl);
  background: var(--bg-surface);
  cursor: pointer;
  transition: all var(--transition);
  text-align: center;
  min-height: 280px;
}
.file-drop-zone:hover, .file-drop-zone.dragover {
  border-color: var(--accent-main);
  background: rgba(124,92,252,0.05);
  box-shadow: 0 0 40px var(--accent-glow);
}
.file-drop-zone:focus-visible { outline: 2px solid var(--border-focus); outline-offset: 2px; }

.file-drop-icon {
  color: var(--text-muted);
  transition: color var(--transition), transform var(--transition);
}
.file-drop-zone:hover .file-drop-icon, .file-drop-zone.dragover .file-drop-icon {
  color: var(--accent-main);
  transform: scale(1.1) translateY(-4px);
}

.file-drop-text {
  font-size: 1.1rem;
  font-weight: 600;
  color: var(--text-primary);
}
.file-drop-sub { font-size: 0.9rem; color: var(--text-muted); }
.link-text {
  color: var(--accent-main);
  cursor: pointer;
  transition: color var(--transition);
}
.link-text:hover { color: var(--accent-hover); }

/* File result area */
.file-result {
  background: var(--bg-surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  overflow: hidden;
  min-width: 0;
}

.file-info {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 16px 20px;
  border-bottom: 1px solid var(--border-subtle);
  background: var(--bg-elevated);
  color: var(--text-secondary);
  min-width: 0;
}

.file-info > svg {
  flex-shrink: 0;
}

.file-details {
  flex: 1;
  display: flex;
  flex-direction: column;
  gap: 2px;
  min-width: 0;
}

.file-name {
  font-size: 0.9rem;
  font-weight: 500;
  color: var(--text-primary);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.file-size {
  font-size: 0.75rem;
  color: var(--text-muted);
  font-family: var(--font-mono);
}

/* Progress */
.file-progress {
  padding: 20px 20px;
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.progress-bar-track {
  height: 4px;
  background: var(--border);
  border-radius: 99px;
  overflow: hidden;
}

.progress-bar-fill {
  height: 100%;
  background: linear-gradient(90deg, var(--accent-main), var(--accent-2));
  border-radius: 99px;
  width: 0%;
  transition: width 0.2s ease;
}

.progress-label {
  font-size: 0.8rem;
  color: var(--text-muted);
  text-align: center;
}

.file-output-section { padding: 0; }

/* File result card — replaces the old textarea output area */
.file-result-card {
  padding: 24px 20px;
  display: flex;
  flex-direction: column;
  gap: 18px;
}

.file-result-stats {
  font-size: 0.82rem;
  font-family: var(--font-mono);
  color: var(--text-secondary);
  background: var(--bg-elevated);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-sm);
  padding: 10px 14px;
  line-height: 1.6;
  word-break: break-all;
}

.file-result-actions {
  display: flex;
  align-items: center;
  gap: 10px;
  flex-wrap: wrap;
}

/* disabled state for primary/secondary buttons */
.btn-primary:disabled,
.btn-secondary:disabled {
  opacity: 0.4;
  pointer-events: none;
  box-shadow: none;
  transform: none;
}

/* ── History ── */
.history-section {
  margin-top: 40px;
}

.section-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 16px;
}

.section-title {
  font-size: 1rem;
  font-weight: 600;
  color: var(--text-secondary);
  letter-spacing: -0.01em;
}

.history-list {
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.empty-state {
  text-align: center;
  color: var(--text-muted);
  font-size: 0.88rem;
  padding: 32px;
  background: var(--bg-surface);
  border: 1px dashed var(--border);
  border-radius: var(--radius-lg);
}

/* History Item */
.history-item {
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 12px;
  align-items: center;
  padding: 12px 16px;
  background: var(--bg-surface);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  cursor: pointer;
  transition: all var(--transition);
  animation: slideIn 0.18s ease;
}

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

.history-item:hover {
  border-color: var(--accent-main);
  background: var(--bg-elevated);
  transform: translateX(2px);
}

.history-item-left {
  min-width: 0;
  display: flex;
  flex-direction: column;
  gap: 3px;
}

.history-item-op {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-size: 0.72rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.08em;
}
.history-item-op.encode { color: var(--accent-main); }
.history-item-op.decode { color: var(--accent-2); }

.history-item-text {
  font-size: 0.82rem;
  color: var(--text-secondary);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
  font-family: var(--font-mono);
}

.history-item-time {
  font-size: 0.72rem;
  color: var(--text-muted);
}

.history-item-actions {
  display: flex;
  gap: 4px;
  opacity: 0;
  transition: opacity var(--transition);
}
.history-item:hover .history-item-actions { opacity: 1; }

/* ── Advanced Panel ── */
.overlay {
  position: fixed;
  inset: 0;
  background: rgba(0,0,0,0.5);
  backdrop-filter: blur(4px);
  z-index: 200;
  cursor: pointer;
  transition: opacity var(--transition-slow);
}
.overlay.hidden { display: none !important; }

.advanced-panel {
  position: fixed;
  top: 0;
  right: 0;
  bottom: 0;
  width: var(--panel-width);
  max-width: 100vw;
  background: var(--bg-surface);
  border-left: 1px solid var(--border);
  z-index: 300;
  transform: translateX(100%);
  transition: transform var(--transition-slow) cubic-bezier(0.4, 0, 0.2, 1);
  overflow-y: auto;
  overflow-x: hidden;
}

.advanced-panel.open {
  transform: translateX(0);
  box-shadow: -8px 0 40px rgba(0,0,0,0.4);
}

.advanced-panel-inner { padding: 0 0 40px; }

.advanced-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 20px 24px;
  border-bottom: 1px solid var(--border);
  position: sticky;
  top: 0;
  background: var(--bg-surface);
  z-index: 10;
}

.advanced-title {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 0.95rem;
  font-weight: 600;
  color: var(--text-primary);
}

.advanced-body { padding: 8px 0; }

.adv-group {
  padding: 20px 24px;
  border-bottom: 1px solid var(--border-subtle);
}
.adv-group:last-child { border-bottom: none; }

.adv-group-title {
  font-size: 0.75rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--text-muted);
  margin-bottom: 16px;
}
.adv-group-title.danger { color: var(--error); }

.adv-label {
  display: flex;
  align-items: center;
  gap: 6px;
  font-size: 0.82rem;
  font-weight: 500;
  color: var(--text-secondary);
  margin-bottom: 8px;
  margin-top: 14px;
}
.adv-label:first-child { margin-top: 0; }

.adv-label-inline {
  display: flex;
  align-items: center;
  gap: 6px;
  font-size: 0.82rem;
  font-weight: 500;
  color: var(--text-secondary);
  flex: 1;
}

.adv-select, .adv-input {
  width: 100%;
  padding: 9px 12px;
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  color: var(--text-primary);
  font-size: 0.85rem;
  font-family: var(--font-sans);
  transition: border-color var(--transition), box-shadow var(--transition);
  appearance: none;
  -webkit-appearance: none;
}
.adv-select:focus, .adv-input:focus {
  border-color: var(--border-focus);
  box-shadow: 0 0 0 3px var(--accent-glow);
  outline: none;
}
.adv-select { background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='12' viewBox='0 0 24 24' fill='none' stroke='%239090c0' stroke-width='2' stroke-linecap='round' stroke-linejoin='round'%3E%3Cpolyline points='6 9 12 15 18 9'/%3E%3C/svg%3E"); background-repeat: no-repeat; background-position: right 10px center; padding-right: 32px; }

.adv-row {
  display: flex;
  align-items: center;
  gap: 10px;
}
.adv-row .adv-input { flex: 1; }
.adv-unit { font-size: 0.78rem; color: var(--text-muted); white-space: nowrap; }

.adv-toggle-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  padding: 10px 0;
  cursor: pointer;
  border-bottom: 1px solid var(--border-subtle);
}
.adv-toggle-row:last-child { border-bottom: none; }

/* Toggle switch */
.toggle-switch {
  position: relative;
  width: 40px;
  height: 22px;
  background: var(--bg-overlay);
  border: 1px solid var(--border);
  border-radius: 99px;
  cursor: pointer;
  transition: background var(--transition), border-color var(--transition);
  flex-shrink: 0;
}
.toggle-switch[aria-checked="true"] {
  background: var(--accent-main);
  border-color: var(--accent-main);
}
.toggle-switch:focus-visible { outline: 2px solid var(--border-focus); outline-offset: 2px; }
.toggle-knob {
  position: absolute;
  top: 2px; left: 2px;
  width: 16px; height: 16px;
  background: #fff;
  border-radius: 50%;
  box-shadow: var(--shadow-sm);
  transition: transform var(--transition);
}
.toggle-switch[aria-checked="true"] .toggle-knob { transform: translateX(18px); }

/* Tooltip */
.tooltip {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 16px; height: 16px;
  border-radius: 50%;
  background: var(--bg-overlay);
  color: var(--text-muted);
  font-size: 0.7rem;
  font-weight: 700;
  cursor: help;
  position: relative;
  font-style: normal;
}
.tooltip::after {
  content: attr(data-tip);
  position: absolute;
  bottom: calc(100% + 8px);
  left: 50%;
  transform: translateX(-50%);
  min-width: 200px;
  max-width: 260px;
  background: var(--bg-overlay);
  color: var(--text-primary);
  font-size: 0.75rem;
  font-weight: 400;
  line-height: 1.5;
  padding: 8px 12px;
  border-radius: var(--radius-md);
  border: 1px solid var(--border);
  box-shadow: var(--shadow-md);
  white-space: normal;
  pointer-events: none;
  opacity: 0;
  transition: opacity var(--transition);
  z-index: 999;
}
.tooltip:hover::after { opacity: 1; }

/* Storage info */
.adv-storage-info {
  display: flex;
  align-items: center;
  gap: 8px;
  margin-top: 12px;
  padding: 10px 12px;
  background: var(--bg-elevated);
  border-radius: var(--radius-sm);
  font-size: 0.78rem;
  color: var(--text-muted);
}

.adv-desc {
  font-size: 0.82rem;
  color: var(--text-muted);
  line-height: 1.5;
  margin-bottom: 14px;
}

.danger-zone { background: rgba(255,107,107,0.03); }

/* ── Toast ── */
.toast-container {
  position: fixed;
  bottom: 24px;
  right: 24px;
  z-index: 9999;
  display: flex;
  flex-direction: column;
  gap: 10px;
  pointer-events: none;
}

.toast {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 12px 18px;
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  font-size: 0.85rem;
  color: var(--text-primary);
  box-shadow: var(--shadow-lg);
  pointer-events: auto;
  animation: toastIn 0.25s cubic-bezier(0.34, 1.56, 0.64, 1);
  max-width: 340px;
  backdrop-filter: blur(10px);
}
.toast.fadeout { animation: toastOut 0.25s ease forwards; }

@keyframes toastIn {
  from { opacity: 0; transform: translateX(20px) scale(0.96); }
  to   { opacity: 1; transform: translateX(0) scale(1); }
}
@keyframes toastOut {
  to   { opacity: 0; transform: translateX(20px) scale(0.96); }
}

.toast.success { border-color: rgba(61,214,140,0.4); }
.toast.error   { border-color: rgba(255,107,107,0.4); }
.toast .toast-icon { font-size: 1rem; flex-shrink: 0; }

/* ── Modal ── */
.modal-backdrop {
  position: fixed;
  inset: 0;
  background: rgba(0,0,0,0.7);
  backdrop-filter: blur(6px);
  z-index: 9000;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 20px;
  animation: fadeIn 0.2s ease;
}

.modal {
  background: var(--bg-surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 28px;
  max-width: 400px;
  width: 100%;
  box-shadow: var(--shadow-lg);
}

.modal-title {
  font-size: 1rem;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: 10px;
}

.modal-body {
  font-size: 0.88rem;
  color: var(--text-secondary);
  line-height: 1.6;
  margin-bottom: 24px;
}

.modal-actions {
  display: flex;
  justify-content: flex-end;
  gap: 10px;
}

/* ── Theme icons ── */
#icon-moon { display: none; }
[data-theme="light"] #icon-sun  { display: none; }
[data-theme="light"] #icon-moon { display: block; }

/* ── Responsive ── */
@media (max-width: 720px) {
  .dual-pane {
    grid-template-columns: 1fr;
    grid-template-rows: auto auto auto;
  }
  .swap-col {
    justify-content: center;
    padding-top: 0;
  }
  .btn-swap { transform: rotate(90deg); }
  .btn-swap:hover { transform: rotate(270deg); }
  .app-main { padding: 20px 16px 60px; }
  .mode-tab { padding: 8px 16px; }
  :root { --panel-width: 100vw; }
  .advanced-panel { border-left: none; }
  .operation-btns { flex-wrap: wrap; }
}

@media (max-width: 480px) {
  .hero-title { font-size: 1.6rem; }
  .pane-textarea { min-height: 160px; }
  .file-drop-zone { padding: 40px 20px; min-height: 200px; }
}

/* ── Scrollbar ── */
::-webkit-scrollbar { width: 6px; height: 6px; }
::-webkit-scrollbar-track { background: transparent; }
::-webkit-scrollbar-thumb { background: var(--border); border-radius: 99px; }
::-webkit-scrollbar-thumb:hover { background: var(--text-muted); }

/* ── Focus ring for accessibility ── */
:focus-visible {
  outline: 2px solid var(--border-focus);
  outline-offset: 2px;
}

/* ── Selection ── */
::selection {
  background: var(--accent-glow);
  color: var(--text-primary);
}