/* ─── Variables ─────────────────────────────────────────────────────────── */
:root {
  --c-bg:         #0f1117;
  --c-surface:    #1a1d27;
  --c-surface-2:  #21253a;
  --c-surface-3:  #272b40;
  --c-border:     #2d3148;
  --c-border-2:   #3a3f5c;
  --c-text:       #c8cde8;
  --c-text-dim:   #6b7299;
  --c-text-bright:#e8eaf6;
  --c-accent:     #4c8eff;
  --c-accent-dim: #1e3a6e;
  --c-success:    #4cd96b;
  --c-success-bg: #0d2318;
  --c-error:      #ff5c72;
  --c-error-bg:   #2b0d14;
  --c-warning:    #ffc94d;
  --c-warning-bg: #2b1d03;
  --c-info-bg:    #0d1828;

  --radius:       6px;
  --radius-lg:    10px;
  --gap:          12px;
  --sidebar-w:    220px;
  --header-h:     48px;
  --transition:   140ms ease;

  --font-ui:      system-ui, -apple-system, "Segoe UI", sans-serif;
  --font-code:    "JetBrains Mono", "Fira Code", "Cascadia Code", Consolas, "Courier New", monospace;
}

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

html, body {
  height: 100%;
  background: var(--c-bg);
  color: var(--c-text);
  font-family: var(--font-ui);
  font-size: 14px;
  line-height: 1.5;
  -webkit-font-smoothing: antialiased;
}

a { color: var(--c-accent); text-decoration: none; }
button { cursor: pointer; font: inherit; }
select { font: inherit; }
input, textarea { font: inherit; }

/* ─── Scrollbars ────────────────────────────────────────────────────────── */
::-webkit-scrollbar { width: 6px; height: 6px; }
::-webkit-scrollbar-track { background: transparent; }
::-webkit-scrollbar-thumb { background: var(--c-border-2); border-radius: 99px; }
::-webkit-scrollbar-thumb:hover { background: var(--c-text-dim); }

/* ─── App Shell ─────────────────────────────────────────────────────────── */
#app {
  display: flex;
  flex-direction: column;
  height: 100vh;
  overflow: hidden;
}

/* ─── Header ────────────────────────────────────────────────────────────── */
.header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: var(--header-h);
  padding: 0 16px;
  background: var(--c-surface);
  border-bottom: 1px solid var(--c-border);
  flex-shrink: 0;
  z-index: 10;
}

.logo {
  display: flex;
  align-items: center;
  gap: 8px;
  color: var(--c-text-bright);
  font-weight: 600;
  font-size: 15px;
  letter-spacing: -0.01em;
  text-decoration: none;
  transition: color var(--transition);
}
.logo:hover { color: #fff; }
.logo svg { color: var(--c-accent); flex-shrink: 0; }

.nav-toggle {
  display: none;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  width: 32px;
  height: 32px;
  background: none;
  border: none;
  padding: 4px;
  border-radius: var(--radius);
}
.nav-toggle span {
  display: block;
  height: 2px;
  background: var(--c-text);
  border-radius: 2px;
  transition: var(--transition);
}
.nav-toggle:hover span { background: var(--c-text-bright); }

/* ─── Layout ────────────────────────────────────────────────────────────── */
.layout {
  display: flex;
  flex: 1;
  overflow: hidden;
}

/* ─── Sidebar ───────────────────────────────────────────────────────────── */
.sidebar {
  width: var(--sidebar-w);
  flex-shrink: 0;
  background: var(--c-surface);
  border-right: 1px solid var(--c-border);
  overflow-y: auto;
  padding: 8px 0;
}

.nav {
  display: flex;
  flex-direction: column;
}

.nav-section {
  padding: 12px 12px 4px;
  font-size: 10px;
  font-weight: 600;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--c-text-dim);
}

.nav-item {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 7px 12px;
  color: var(--c-text);
  font-size: 13px;
  text-decoration: none;
  border-radius: 0;
  transition: background var(--transition), color var(--transition);
  border-left: 2px solid transparent;
}
.nav-item:hover {
  background: var(--c-surface-2);
  color: var(--c-text-bright);
}
.nav-item--active {
  background: var(--c-accent-dim);
  color: var(--c-accent);
  border-left-color: var(--c-accent);
  font-weight: 500;
}
.nav-item:focus-visible {
  outline: 2px solid var(--c-accent);
  outline-offset: -2px;
}
.nav-item--home { color: var(--c-text-dim); font-size: 12px; }
.nav-item--home:hover { color: var(--c-text); }

/* ─── Main ──────────────────────────────────────────────────────────────── */
.main {
  flex: 1;
  overflow: hidden;
  display: flex;
  flex-direction: column;
}

/* ─── Home Page ─────────────────────────────────────────────────────────── */
.home {
  flex: 1;
  overflow-y: auto;
  padding: 40px 32px;
}

.home-title {
  font-size: 28px;
  font-weight: 700;
  color: var(--c-text-bright);
  letter-spacing: -0.02em;
  margin-bottom: 8px;
}

.home-subtitle {
  color: var(--c-text-dim);
  margin-bottom: 32px;
  font-size: 14px;
}

.cards {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
  gap: 14px;
}

.card {
  display: flex;
  flex-direction: column;
  gap: 6px;
  padding: 18px 20px;
  background: var(--c-surface);
  border: 1px solid var(--c-border);
  border-radius: var(--radius-lg);
  text-decoration: none;
  color: inherit;
  transition: border-color var(--transition), background var(--transition), transform var(--transition);
}
.card:hover {
  border-color: var(--c-accent);
  background: var(--c-surface-2);
  transform: translateY(-1px);
}

.card-title {
  font-size: 15px;
  font-weight: 600;
  color: var(--c-text-bright);
}

.card-route {
  font-family: var(--font-code);
  font-size: 11px;
  color: var(--c-text-dim);
}

.home-empty {
  color: var(--c-text-dim);
  font-style: italic;
}

/* ─── Tool Shell ────────────────────────────────────────────────────────── */
.tool {
  display: flex;
  flex-direction: column;
  height: 100%;
  overflow: hidden;
}

.tool-topbar {
  flex-shrink: 0;
  padding: 14px 16px 0;
  background: var(--c-bg);
  border-bottom: 1px solid var(--c-border);
}

.tool-title {
  font-size: 17px;
  font-weight: 600;
  color: var(--c-text-bright);
  letter-spacing: -0.01em;
  margin-bottom: 12px;
}

/* ─── Toolbar ───────────────────────────────────────────────────────────── */
.toolbar {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 6px;
  padding-bottom: 10px;
}

.toolbar-sep {
  width: 1px;
  height: 20px;
  background: var(--c-border-2);
  margin: 0 2px;
  flex-shrink: 0;
}

.label-inline {
  font-size: 12px;
  color: var(--c-text-dim);
  white-space: nowrap;
}

/* ─── Notification ──────────────────────────────────────────────────────── */
.notif-area {
  min-height: 0;
  overflow: hidden;
}

.notification {
  padding: 7px 12px;
  border-radius: var(--radius);
  font-size: 13px;
  font-family: var(--font-code);
  line-height: 1.4;
  margin-bottom: 8px;
  white-space: pre-wrap;
  word-break: break-word;
}
.notification[data-type="error"] {
  background: var(--c-error-bg);
  color: var(--c-error);
  border: 1px solid color-mix(in srgb, var(--c-error) 30%, transparent);
}
.notification[data-type="success"] {
  background: var(--c-success-bg);
  color: var(--c-success);
  border: 1px solid color-mix(in srgb, var(--c-success) 30%, transparent);
}
.notification[data-type="info"] {
  background: var(--c-info-bg);
  color: var(--c-text);
  border: 1px solid var(--c-border);
}
.notification[data-type="warning"] {
  background: var(--c-warning-bg);
  color: var(--c-warning);
  border: 1px solid color-mix(in srgb, var(--c-warning) 25%, transparent);
}

/* ─── Two-Panel Layout ──────────────────────────────────────────────────── */
.panels {
  flex: 1;
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--gap);
  padding: var(--gap);
  overflow: hidden;
  background: var(--c-bg);
}

.panel {
  display: flex;
  flex-direction: column;
  background: var(--c-surface);
  border: 1px solid var(--c-border);
  border-radius: var(--radius-lg);
  overflow: hidden;
  min-height: 0;
}

.panel-label {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 8px 12px;
  font-size: 11px;
  font-weight: 600;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--c-text-dim);
  background: var(--c-surface-2);
  border-bottom: 1px solid var(--c-border);
  flex-shrink: 0;
  user-select: none;
}

.panel.drag-over {
  border-color: var(--c-accent);
  box-shadow: 0 0 0 2px var(--c-accent-dim);
}

/* ─── Code Editor / Output ──────────────────────────────────────────────── */
.code-editor {
  flex: 1;
  resize: none;
  background: transparent;
  border: none;
  outline: none; /* panel border provides visual containment */
  color: var(--c-text-bright);
  font-family: var(--font-code);
  font-size: 13px;
  line-height: 1.65;
  padding: 12px;
  overflow: auto;
  caret-color: var(--c-accent);
}
.code-editor::placeholder { color: var(--c-text-dim); }
.code-editor:focus-visible { outline: 2px solid var(--c-accent); outline-offset: -2px; }

.code-output {
  flex: 1;
  overflow: auto;
  padding: 12px;
  font-family: var(--font-code);
  font-size: 13px;
  line-height: 1.65;
  color: var(--c-text-bright);
  white-space: pre;
  min-height: 0;
  background: transparent;
  border: none;
  outline: none;
  user-select: text;
}
.code-output:empty::before {
  content: "Output will appear here…";
  color: var(--c-text-dim);
  font-style: italic;
}

/* ─── Buttons ───────────────────────────────────────────────────────────── */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 5px;
  padding: 5px 12px;
  border-radius: var(--radius);
  border: 1px solid var(--c-border-2);
  background: var(--c-surface-3);
  color: var(--c-text);
  font-size: 13px;
  font-weight: 500;
  white-space: nowrap;
  transition: background var(--transition), border-color var(--transition), color var(--transition);
  cursor: pointer;
  text-decoration: none;
}
.btn:hover:not(:disabled) {
  background: var(--c-surface-2);
  border-color: var(--c-border-2);
  color: var(--c-text-bright);
}
.btn:focus-visible {
  outline: 2px solid var(--c-accent);
  outline-offset: 2px;
}
.btn:active:not(:disabled) { opacity: 0.85; }
.btn:disabled {
  opacity: 0.4;
  cursor: not-allowed;
}

.btn--primary {
  background: var(--c-accent);
  border-color: var(--c-accent);
  color: #fff;
}
.btn--primary:hover:not(:disabled) {
  background: color-mix(in srgb, var(--c-accent) 85%, #fff);
  border-color: color-mix(in srgb, var(--c-accent) 85%, #fff);
  color: #fff;
}

.btn--danger {
  border-color: color-mix(in srgb, var(--c-error) 40%, transparent);
  color: var(--c-error);
}
.btn--danger:hover:not(:disabled) {
  background: var(--c-error-bg);
  border-color: var(--c-error);
}

.btn--sm {
  padding: 3px 8px;
  font-size: 11px;
  border-radius: 4px;
}

/* ─── Select ────────────────────────────────────────────────────────────── */
.select {
  padding: 4px 28px 4px 9px;
  border-radius: var(--radius);
  border: 1px solid var(--c-border-2);
  background: var(--c-surface-3);
  color: var(--c-text);
  font-size: 13px;
  appearance: none;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='12' viewBox='0 0 12 12'%3E%3Cpath d='M2 4l4 4 4-4' stroke='%236b7299' stroke-width='1.5' fill='none' stroke-linecap='round'/%3E%3C/svg%3E");
  background-repeat: no-repeat;
  background-position: right 8px center;
  cursor: pointer;
  transition: border-color var(--transition);
}
.select:hover { border-color: var(--c-border-2); }
.select:focus { outline: 2px solid var(--c-accent); outline-offset: 1px; border-color: var(--c-accent); }

/* ─── Checkbox ──────────────────────────────────────────────────────────── */
.checkbox-wrap {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  color: var(--c-text);
  font-size: 13px;
  cursor: pointer;
  white-space: nowrap;
  user-select: none;
}
.checkbox-wrap input[type="checkbox"] {
  width: 14px;
  height: 14px;
  accent-color: var(--c-accent);
  cursor: pointer;
  flex-shrink: 0;
}

/* ─── Footer ────────────────────────────────────────────────────────────── */
.site-footer {
  flex-shrink: 0;
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 4px 20px;
  padding: 7px 16px;
  background: var(--c-surface);
  border-top: 1px solid var(--c-border);
  font-size: 11px;
  color: var(--c-text-dim);
  line-height: 1.5;
}

.site-footer a {
  color: var(--c-text-dim);
  text-decoration: none;
  transition: color var(--transition);
}
.site-footer a:hover { color: var(--c-text-bright); }
.site-footer a:focus-visible {
  outline: 2px solid var(--c-accent);
  outline-offset: 2px;
  border-radius: 2px;
}

.site-footer-links {
  display: flex;
  align-items: center;
  gap: 4px 8px;
  flex-wrap: wrap;
}

.site-footer-sep { color: var(--c-border-2); user-select: none; }

.site-footer-disclaimer { font-style: italic; }

/* ─── Responsive ────────────────────────────────────────────────────────── */
@media (max-width: 768px) {
  .nav-toggle { display: flex; }

  .sidebar {
    position: fixed;
    top: var(--header-h);
    left: 0;
    bottom: 0;
    z-index: 100;
    transform: translateX(-100%);
    transition: transform var(--transition);
    box-shadow: 4px 0 24px rgba(0, 0, 0, 0.4);
  }
  .sidebar--open { transform: translateX(0); }

  .panels {
    grid-template-columns: 1fr;
    overflow-y: auto;
    overflow-x: hidden;
  }

  .panel {
    min-height: 300px;
  }

  .home { padding: 24px 16px; }
  .tool-topbar { padding: 12px 12px 0; }
  .toolbar { gap: 5px; }
}

@media (max-width: 480px) {
  .cards { grid-template-columns: 1fr; }
}