:root {
  --b64-accent:      #f59e0b;
  --b64-accent-2:    #d97706;
  --b64-accent-soft: rgba(245, 158, 11, 0.14);
  --b64-accent-line: rgba(245, 158, 11, 0.55);
  --b64-surface:     rgba(255, 255, 255, 0.03);
  --b64-surface-2:   rgba(255, 255, 255, 0.05);
  --b64-border:      rgba(255, 255, 255, 0.08);
  --b64-border-str:  rgba(255, 255, 255, 0.16);
  --b64-text:        rgba(255, 255, 255, 0.88);
  --b64-text-dim:    rgba(255, 255, 255, 0.55);
  --b64-radius:      14px;
  --b64-mono:        'JetBrains Mono', 'Cascadia Code', 'Fira Mono', monospace;
}

/* ---------- Shell ---------- */
.b64-shell {
  max-width: 1300px;
  margin: 0 auto;
  padding: 1.1rem 1.25rem 3rem;
}
.b64-back {
  color: var(--b64-text-dim);
  text-decoration: none;
  font-size: 0.85rem;
  transition: color 0.2s;
}
.b64-back:hover { color: var(--b64-accent); }

/* ---------- Hero ---------- */
.b64-hero { text-align: center; padding: 1.4rem 0 1.1rem; }
.b64-hero-kicker {
  display: inline-block;
  font-size: 0.66rem;
  font-weight: 800;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--b64-accent);
  margin-bottom: 0.45rem;
}
.b64-hero-title {
  font-size: clamp(1.7rem, 3.4vw, 2.6rem);
  font-weight: 800;
  margin: 0 0 0.5rem;
  background: linear-gradient(135deg, var(--b64-accent), var(--b64-accent-2));
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
}
.b64-hero-sub {
  color: var(--b64-text-dim);
  margin: 0 auto;
  max-width: 640px;
  font-size: 0.96rem;
  line-height: 1.5;
}
.b64-hero-chips {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 0.5rem;
  margin-top: 1rem;
}
.b64-chip {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  font-size: 0.74rem;
  color: var(--b64-text-dim);
  border: 1px solid var(--b64-border);
  background: var(--b64-surface);
  border-radius: 999px;
  padding: 0.3rem 0.7rem;
}
.b64-chip-dot {
  width: 6px; height: 6px; border-radius: 50%;
  background: linear-gradient(135deg, var(--b64-accent), var(--b64-accent-2));
  box-shadow: 0 0 8px rgba(245, 158, 11, 0.55);
}

/* ---------- Operation tab bar ---------- */
.b64-op-bar {
  display: flex;
  gap: 0.4rem;
  flex-wrap: wrap;
  margin: 0.8rem 0 0.55rem;
}
.b64-op-tab {
  appearance: none;
  border: 1px solid var(--b64-border-str);
  background: var(--b64-surface-2);
  color: var(--b64-text-dim);
  font-size: 0.8rem;
  font-weight: 600;
  padding: 0.42rem 1rem;
  border-radius: 999px;
  cursor: pointer;
  transition: all 0.18s;
  white-space: nowrap;
  font-family: inherit;
}
.b64-op-tab:hover { color: #fff; }
.b64-op-tab.active {
  background: linear-gradient(135deg, var(--b64-accent), var(--b64-accent-2));
  border-color: transparent;
  color: #fff;
  box-shadow: 0 4px 14px rgba(245, 158, 11, 0.3);
}

/* ---------- Options bar ---------- */
.b64-opts-bar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0.5rem 0.85rem;
  border: 1px solid var(--b64-border);
  border-radius: 10px;
  background: var(--b64-surface);
  margin-bottom: 0.75rem;
  gap: 0.75rem;
  flex-wrap: wrap;
}
.b64-opts-left, .b64-opts-right {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  flex-wrap: wrap;
}
.b64-opts-label {
  display: flex;
  align-items: center;
  gap: 0.4rem;
  font-size: 0.78rem;
  color: var(--b64-text-dim);
}
.b64-select {
  padding: 0.3rem 0.55rem;
  border-radius: 7px;
  border: 1px solid var(--b64-border-str);
  background: rgba(255,255,255,0.06);
  color: #fff;
  font-size: 0.8rem;
  font-family: inherit;
  outline: none;
  cursor: pointer;
  transition: border-color 0.18s, box-shadow 0.18s;
}
.b64-select:focus {
  border-color: var(--b64-accent-line);
  box-shadow: 0 0 0 3px var(--b64-accent-soft);
}
.b64-select option { background: #0b1220; }

/* ---------- Workspace ---------- */
.b64-workspace {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 0.85rem;
  align-items: start;
}

/* ---------- Panels ---------- */
.b64-panel {
  border: 1px solid var(--b64-border);
  border-radius: var(--b64-radius);
  background:
    radial-gradient(circle at 100% 0%, rgba(245, 158, 11, 0.05), transparent 50%),
    var(--b64-surface);
  display: flex;
  flex-direction: column;
  min-height: 460px;
}
.b64-panel-head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0.6rem 0.9rem;
  border-bottom: 1px solid var(--b64-border);
  gap: 0.5rem;
  flex-wrap: wrap;
}
.b64-panel-head-left {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  flex: 1;
  min-width: 0;
  flex-wrap: wrap;
}
.b64-panel-title {
  font-size: 0.72rem;
  font-weight: 700;
  letter-spacing: 0.09em;
  text-transform: uppercase;
  color: var(--b64-text-dim);
  white-space: nowrap;
}
.b64-panel-actions {
  display: flex;
  align-items: center;
  gap: 0.35rem;
  flex-shrink: 0;
}

/* ---------- Detect badge ---------- */
.b64-detect-badge {
  font-size: 0.62rem;
  font-weight: 800;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  padding: 0.12rem 0.45rem;
  border-radius: 4px;
  background: var(--b64-accent-soft);
  border: 1px solid var(--b64-accent-line);
  color: var(--b64-accent);
}
.b64-detect-badge.b64 {
  background: rgba(34,197,94,0.1);
  border-color: rgba(34,197,94,0.45);
  color: #86efac;
}
.b64-detect-badge.text {
  background: rgba(96,165,250,0.1);
  border-color: rgba(96,165,250,0.45);
  color: #93c5fd;
}

/* ---------- File chip ---------- */
.b64-file-chip {
  font-size: 0.65rem;
  color: var(--b64-text-dim);
  background: var(--b64-surface-2);
  border: 1px solid var(--b64-border);
  border-radius: 4px;
  padding: 0.1rem 0.4rem;
  max-width: 160px;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

/* ---------- Byte count ---------- */
.b64-byte-count {
  font-size: 0.66rem;
  color: var(--b64-text-dim);
  white-space: nowrap;
}

/* ---------- Output chips ---------- */
.b64-out-chips {
  display: flex;
  gap: 0.35rem;
  align-items: center;
  flex-wrap: wrap;
}
.b64-chip-sm {
  font-size: 0.62rem;
  font-weight: 600;
  padding: 0.12rem 0.45rem;
  border-radius: 4px;
  background: var(--b64-surface-2);
  border: 1px solid var(--b64-border);
  color: var(--b64-text-dim);
  white-space: nowrap;
}
.b64-validity-chip {
  font-size: 0.62rem;
  font-weight: 700;
  padding: 0.12rem 0.45rem;
  border-radius: 4px;
  white-space: nowrap;
}
.b64-validity-chip.valid {
  background: rgba(34,197,94,0.1);
  border: 1px solid rgba(34,197,94,0.35);
  color: #86efac;
}
.b64-validity-chip.error {
  background: rgba(239,68,68,0.1);
  border: 1px solid rgba(239,68,68,0.35);
  color: #f87171;
}

/* ---------- Textareas ---------- */
.b64-textarea {
  flex: 1;
  font-family: var(--b64-mono);
  font-size: 0.83rem;
  line-height: 1.6;
  padding: 0.75rem;
  box-sizing: border-box;
  border: none;
  outline: none;
  background: transparent;
  color: var(--b64-text);
  resize: vertical;
  min-height: 380px;
  white-space: pre;
  overflow: auto;
  tab-size: 2;
}
.b64-textarea::placeholder { color: rgba(255,255,255,0.2); font-style: italic; }
.b64-textarea-out { color: rgba(255,255,255,0.75); cursor: default; }

/* ---------- Image preview ---------- */
.b64-preview {
  border-top: 1px solid var(--b64-border);
  padding: 0.75rem;
  animation: b64FadeIn 0.3s ease;
}
@keyframes b64FadeIn {
  from { opacity: 0; transform: translateY(6px); }
  to   { opacity: 1; transform: translateY(0); }
}
.b64-preview-head {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  margin-bottom: 0.55rem;
}
.b64-preview-label {
  font-size: 0.68rem;
  font-weight: 700;
  letter-spacing: 0.07em;
  text-transform: uppercase;
  color: var(--b64-text-dim);
}
.b64-preview-meta {
  font-size: 0.65rem;
  color: var(--b64-text-dim);
}
.b64-preview-img {
  max-width: 100%;
  max-height: 320px;
  border-radius: 8px;
  border: 1px solid var(--b64-border);
  display: block;
  object-fit: contain;
}

/* ---------- Status bar ---------- */
.b64-status-bar {
  margin-top: 0.65rem;
  padding: 0.45rem 0.75rem;
  border-radius: 8px;
  font-size: 0.8rem;
  font-family: var(--b64-mono);
  min-height: 2rem;
  display: flex;
  align-items: center;
  transition: background 0.2s;
}
.b64-status-bar:empty { display: none; }
.b64-status-bar.valid   { background: rgba(34,197,94,0.08);   color: #86efac; border: 1px solid rgba(34,197,94,0.25); }
.b64-status-bar.error   { background: rgba(239,68,68,0.08);   color: #f87171; border: 1px solid rgba(239,68,68,0.25); }
.b64-status-bar.info    { background: rgba(245,158,11,0.08);  color: var(--b64-accent); border: 1px solid var(--b64-accent-line); }

/* ---------- Buttons ---------- */
.b64-btn {
  appearance: none;
  border: 1px solid var(--b64-border-str);
  background: var(--b64-surface-2);
  color: var(--b64-text);
  font-size: 0.8rem;
  font-weight: 600;
  padding: 0.5rem 0.9rem;
  border-radius: 8px;
  cursor: pointer;
  transition: all 0.18s;
  font-family: inherit;
  white-space: nowrap;
  display: inline-flex;
  align-items: center;
  gap: 0.3rem;
}
.b64-btn:hover { border-color: var(--b64-accent-line); transform: translateY(-1px); }
.b64-btn-sm   { font-size: 0.72rem; padding: 0.28rem 0.6rem; border-radius: 6px; }
.b64-btn-ghost { background: transparent; border-color: var(--b64-border); }
.b64-btn.copied { background: rgba(34,197,94,0.15); border-color: rgba(34,197,94,0.4); color: #86efac; }

/* ---------- Modal / shortcuts ---------- */
.b64-modal {
  position: fixed;
  inset: 0;
  z-index: 9000;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 1rem;
  background: rgba(0,0,0,0.65);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
}
.b64-modal[hidden] { display: none; }
.b64-modal-card {
  width: 100%;
  max-width: 440px;
  background: rgba(12,20,32,0.97);
  border: 1px solid var(--b64-border-str);
  border-radius: 16px;
  padding: 1.3rem;
  box-shadow: 0 24px 60px rgba(0,0,0,0.5);
}
.b64-modal-head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 1rem;
}
.b64-modal-head h3 { margin: 0; font-size: 1rem; color: #fff; }
.b64-modal-close {
  background: none; border: none; color: var(--b64-text-dim);
  font-size: 1.5rem; line-height: 1; cursor: pointer;
}
.b64-modal-close:hover { color: #fff; }
.b64-shortcuts-grid {
  display: grid;
  grid-template-columns: auto 1fr;
  gap: 0.5rem 1rem;
  font-size: 0.82rem;
  color: var(--b64-text);
}
.b64-shortcuts-grid kbd {
  display: inline-block;
  padding: 0.1rem 0.35rem;
  background: var(--b64-surface-2);
  border: 1px solid var(--b64-border-str);
  border-radius: 4px;
  font-size: 0.7rem;
  font-family: var(--b64-mono);
}

/* ---------- Toasts ---------- */
.b64-toast-host {
  position: fixed;
  bottom: 1.2rem;
  left: 50%;
  transform: translateX(-50%);
  z-index: 9500;
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
  pointer-events: none;
}
.b64-toast {
  pointer-events: auto;
  min-width: 200px;
  max-width: 360px;
  padding: 0.7rem 1rem;
  border-radius: 10px;
  font-size: 0.84rem;
  color: #fff;
  background: rgba(20,16,10,0.97);
  border: 1px solid var(--b64-border-str);
  box-shadow: 0 12px 30px rgba(0,0,0,0.4);
  opacity: 0;
  transform: translateY(12px);
  transition: opacity 0.3s, transform 0.3s;
  cursor: pointer;
}
.b64-toast.show    { opacity: 1; transform: translateY(0); }
.b64-toast.success { border-color: rgba(34,197,94,0.5); }
.b64-toast.error   { border-color: rgba(239,68,68,0.5); }
.b64-toast.info    { border-color: var(--b64-accent-line); }

/* ---------- Shared ---------- */
.sr-only {
  position: absolute; width: 1px; height: 1px;
  padding: 0; margin: -1px; overflow: hidden;
  clip: rect(0,0,0,0); white-space: nowrap; border: 0;
}

/* ---------- Responsive ---------- */
@media (max-width: 860px) {
  .b64-workspace { grid-template-columns: 1fr; }
  .b64-panel { min-height: 300px; }
  .b64-textarea { min-height: 260px; }
}
@media (max-width: 560px) {
  .b64-op-bar { gap: 0.3rem; }
  .b64-op-tab { font-size: 0.72rem; padding: 0.35rem 0.7rem; }
}