/* === Theme Variables === */
:root {
  --bg-page: #fafafa;
  --bg-surface: #f8f9fa;
  --bg-surface-hover: #f1f3f5;
  --bg-input: #f1f3f5;
  --bg-input-hover: #e9ecef;
  --text-primary: #212529;
  --text-secondary: #868e96;
  --text-muted: #adb5bd;
  --border: #ced4da;
  --border-light: #dee2e6;
  --border-focus: #e9ecef;
  --accent: #228be6;
  --accent-hover: #1c7ed6;
  --error: #e03131;
  --progress-track: #e9ecef;
  --dropzone-hover-bg: #f0f7ff;
  --spinner-track: #e9ecef;
  color-scheme: light dark;
}

[data-theme="dark"] {
  --bg-page: #1a1b1e;
  --bg-surface: #25262b;
  --bg-surface-hover: #2c2e33;
  --bg-input: #2c2e33;
  --bg-input-hover: #373a40;
  --text-primary: #c1c2c5;
  --text-secondary: #909296;
  --text-muted: #5c5f66;
  --border: #373a40;
  --border-light: #2c2e33;
  --border-focus: #25262b;
  --accent: #339af0;
  --accent-hover: #228be6;
  --error: #ff6b6b;
  --progress-track: #373a40;
  --dropzone-hover-bg: #1b2838;
  --spinner-track: #373a40;
}
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --bg-page: #1a1b1e;
    --bg-surface: #25262b;
    --bg-surface-hover: #2c2e33;
    --bg-input: #2c2e33;
    --bg-input-hover: #373a40;
    --text-primary: #c1c2c5;
    --text-secondary: #909296;
    --text-muted: #5c5f66;
    --border: #373a40;
    --border-light: #2c2e33;
    --border-focus: #25262b;
    --accent: #339af0;
    --accent-hover: #228be6;
    --error: #ff6b6b;
    --progress-track: #373a40;
    --dropzone-hover-bg: #1b2838;
    --spinner-track: #373a40;
  }
}

/* === Smooth Transitions for Theme Toggle === */
body, .send-status, .receive-status, .dropzone, .code-box, .mode-tab, .main-tab, .btn, .btn-cancel, .btn-action, .receive-row input, .cli-section {
  transition: background-color 0.2s, color 0.2s, border-color 0.2s;
}

/* === Focus Visible === */
:focus-visible { outline: 2px solid var(--accent); outline-offset: 2px; }
button:focus:not(:focus-visible), input:focus:not(:focus-visible) { outline: none; }

/* === Base === */
*, *::before, *::after { box-sizing: border-box; }
body {
  font-family: system-ui, -apple-system, sans-serif;
  background: var(--bg-page);
  color: var(--text-primary);
  margin: 0;
  padding: 20px;
  min-height: 100vh;
  display: flex;
  justify-content: center;
  align-items: flex-start;
  padding-top: 10vh;
}
.container {
  width: 100%;
  max-width: 480px;
  position: relative;
}
h1 {
  text-align: center;
  font-size: 24px;
  margin: 0 0 4px;
}
.subtitle {
  text-align: center;
  color: var(--text-secondary);
  font-size: 14px;
  margin: 0 0 12px;
}
.warning {
  text-align: center;
  font-size: 12px;
  color: var(--text-secondary);
  margin: 0 0 24px;
  line-height: 1.4;
}
.encrypted {
  text-align: center;
  font-size: 12px;
  color: var(--text-secondary);
  margin: 0 0 24px;
  line-height: 1.4;
}
.transfer-info {
  text-align: center;
  color: var(--text-secondary);
  font-size: 13px;
  margin-top: 4px;
}

/* === Theme Toggle === */
.theme-toggle {
  position: absolute;
  top: 0;
  right: 0;
  background: none;
  border: none;
  cursor: pointer;
  color: var(--text-secondary);
  padding: 4px;
  border-radius: 4px;
  line-height: 1;
}
.theme-toggle:hover { color: var(--text-primary); }

/* === Main Tabs (Send / Receive) === */
.main-tabs {
  display: flex;
  gap: 0;
  margin-bottom: 16px;
  border: 1px solid var(--border);
  border-radius: 8px;
  overflow: hidden;
}
.main-tab {
  flex: 1;
  padding: 10px 0;
  border: none;
  background: var(--bg-surface);
  font-size: 15px;
  font-weight: 500;
  color: var(--text-secondary);
  cursor: pointer;
  transition: background-color 0.15s, color 0.15s;
}
.main-tab:first-child { border-right: 1px solid var(--border); }
.main-tab:hover { background: var(--bg-surface-hover); }
.main-tab.active {
  background: var(--accent);
  color: white;
}

/* === Dropzone === */
.dropzone {
  border: 2px dashed var(--border);
  border-radius: 12px;
  padding: 40px 20px;
  text-align: center;
  cursor: pointer;
  transition: border-color 0.15s, background 0.15s;
  color: var(--text-secondary);
  font-size: 15px;
  animation: pulse 3s ease-in-out infinite;
}
.dropzone:hover, .dropzone.dragover {
  border-color: var(--accent);
  background: var(--dropzone-hover-bg);
  animation: none;
}
.dropzone input { display: none; }

/* === Receive Row === */
.receive-row {
  display: flex;
  gap: 8px;
}
.receive-row input {
  flex: 1;
  padding: 10px 14px;
  border: 1px solid var(--border);
  border-radius: 8px;
  font-size: 15px;
  outline: none;
  background: var(--bg-input);
  color: var(--text-primary);
}
.receive-row input:focus { border-color: var(--accent); }

/* === Buttons === */
.btn {
  padding: 10px 20px;
  background: var(--accent);
  color: white;
  border: none;
  border-radius: 8px;
  font-size: 15px;
  cursor: pointer;
  white-space: nowrap;
}
.btn:hover { background: var(--accent-hover); }
.btn:disabled { background: var(--text-muted); cursor: default; }
.btn-cancel {
  background: none;
  color: var(--text-secondary);
  border: 1px solid var(--border);
  margin-top: 8px;
  width: 100%;
}
.btn-cancel:hover { background: var(--bg-surface-hover); color: var(--text-primary); }

/* === Send Status Panel === */
.send-status {
  border: 2px solid var(--accent);
  border-radius: 12px;
  padding: 20px;
  background: var(--bg-surface);
}
.file-info {
  display: flex;
  align-items: center;
  gap: 10px;
  margin-bottom: 14px;
}
.file-icon { width: 24px; height: 24px; color: var(--text-secondary); flex-shrink: 0; }
.file-name { font-weight: 600; font-size: 14px; }
.file-size { color: var(--text-secondary); font-size: 12px; }
.code-box {
  background: var(--bg-input);
  color: var(--text-primary);
  border: 1px solid var(--border-light);
  border-radius: 8px;
  padding: 12px;
  font-family: 'SF Mono', 'Cascadia Code', 'Fira Code', monospace;
  font-size: 14px;
  text-align: center;
  margin-bottom: 14px;
  user-select: all;
  cursor: pointer;
}
.code-box:hover { background: var(--bg-input-hover); }
.code-actions {
  display: flex;
  gap: 8px;
  justify-content: center;
  margin-bottom: 14px;
}
.btn-action {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 8px 14px;
  background: none;
  border: 1px solid var(--border);
  border-radius: 6px;
  font-size: 13px;
  color: var(--text-primary);
  cursor: pointer;
}
.btn-action:hover { background: var(--bg-surface-hover); }

/* === Mode Tabs === */
.mode-tabs {
  display: flex;
  justify-content: center;
  gap: 0;
  margin-bottom: 12px;
  border: 1px solid var(--border);
  border-radius: 6px;
  overflow: hidden;
}
.mode-tab {
  flex: 1;
  padding: 6px 0;
  border: none;
  background: var(--bg-surface);
  font-size: 13px;
  color: var(--text-secondary);
  cursor: pointer;
}
.mode-tab:not(:last-child) { border-right: 1px solid var(--border); }
.mode-tab:hover { background: var(--bg-input-hover); }
.mode-tab.active {
  background: var(--accent);
  color: white;
}

/* === QR === */
.qr-container { text-align: center; margin-bottom: 14px; }
.qr-container canvas, .qr-container img { margin: 0 auto; }

/* === Progress === */
.progress-track {
  background: var(--progress-track);
  border-radius: 4px;
  height: 6px;
  margin-bottom: 6px;
  overflow: hidden;
}
.progress-bar {
  background: var(--accent);
  height: 100%;
  border-radius: 4px;
  width: 0%;
  transition: width 0.2s;
}
.progress-bar.done { background: var(--accent); animation: none; }
.status-text {
  text-align: center;
  color: var(--text-secondary);
  font-size: 13px;
}
.status-text.error { color: var(--error); }
.status-text.done { color: var(--text-primary); font-weight: 600; }

/* === Receive Status === */
.receive-status {
  text-align: center;
  padding: 20px;
  border: 1px solid var(--border);
  border-radius: 12px;
}
.spinner {
  display: inline-block;
  width: 20px; height: 20px;
  border: 2px solid var(--spinner-track);
  border-top-color: var(--accent);
  border-radius: 50%;
  animation: spin 0.6s linear infinite;
  margin-right: 8px;
  vertical-align: middle;
}
@keyframes spin { to { transform: rotate(360deg); } }

.hidden { display: none; }

/* === CLI & Apps Section === */
.cli-section {
  margin-top: 32px;
  border-top: 1px solid var(--border-focus);
  padding-top: 16px;
}
.cli-section summary {
  cursor: pointer;
  text-align: center;
  color: var(--text-secondary);
  font-size: 13px;
  list-style: none;
  user-select: none;
}
.cli-section summary::-webkit-details-marker { display: none; }
.cli-section summary::before { content: "\25B8 "; }
.cli-section[open] summary::before { content: "\25BE "; }
.cli-content { margin-top: 16px; }
.cli-group { margin-bottom: 16px; }
.cli-group h3 {
  font-size: 12px;
  text-transform: uppercase;
  letter-spacing: 0.5px;
  color: var(--text-secondary);
  margin: 0 0 6px;
}
.cli-links {
  display: flex;
  flex-wrap: wrap;
  gap: 6px 14px;
  font-size: 13px;
}
.cli-links a { color: var(--accent); text-decoration: none; }
.cli-links a:hover { text-decoration: underline; }

/* === Animations === */

/* Dropzone idle pulse */
@keyframes pulse { 0%, 100% { border-color: var(--border); } 50% { border-color: var(--text-muted); } }

/* Progress bar shimmer */
@keyframes shimmer { 0% { background-position: -200% 0; } 100% { background-position: 200% 0; } }
.progress-bar:not(.done) {
  background: linear-gradient(90deg, var(--accent) 0%, color-mix(in srgb, var(--accent) 70%, white) 50%, var(--accent) 100%);
  background-size: 200% 100%;
  animation: shimmer 1.5s ease-in-out infinite;
}

/* Code box fade-in */
@keyframes fadeInUp { from { opacity: 0; transform: translateY(8px); } to { opacity: 1; transform: translateY(0); } }
.send-status:not(.hidden) #send-code-section:not(.hidden) { animation: fadeInUp 0.2s ease-out; }

/* Completion checkmark */
@keyframes checkmark { 0% { stroke-dashoffset: 24; } 100% { stroke-dashoffset: 0; } }
.checkmark-icon { stroke-dasharray: 24; stroke-dashoffset: 24; }
.checkmark-icon.animate { animation: checkmark 0.3s ease-out forwards; }