/* ===========================================================
   Image Joiner — Stylesheet
   Modern, minimalist, light theme with blue accent.
=========================================================== */

:root {
  --accent: #2563eb;
  --accent-dark: #1d4ed8;
  --accent-light: #dbeafe;
  --bg: #eef1f6;
  --panel-bg: #ffffff;
  --border: #e2e6ed;
  --text: #1e2430;
  --text-muted: #6b7280;
  --shadow-sm: 0 1px 3px rgba(20, 25, 35, 0.08);
  --shadow-md: 0 4px 14px rgba(20, 25, 35, 0.10);
  --radius: 12px;
  --radius-sm: 8px;
}

* {
  box-sizing: border-box;
}

html, body {
  height: 100%;
  margin: 0;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  background: var(--bg);
  color: var(--text);
  -webkit-font-smoothing: antialiased;
}

#app {
  display: flex;
  flex-direction: column;
  height: 100vh;
}

/* ================= HEADER ================= */

.app-header {
  flex: none;
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 12px 20px;
  background: var(--panel-bg);
  border-bottom: 1px solid var(--border);
}

.app-logo {
  font-size: 20px;
  line-height: 1;
}

.app-name {
  font-size: 16px;
  font-weight: 700;
  color: var(--text);
  letter-spacing: -0.01em;
}

.main-layout {
  flex: 1 1 auto;
  display: flex;
  min-height: 0;
  gap: 14px;
  padding: 14px;
}

/* ================= PREVIEW PANEL ================= */

.preview-panel {
  flex: 7 1 0;
  min-width: 0;
  background: var(--panel-bg);
  border-radius: var(--radius);
  box-shadow: var(--shadow-sm);
  border: 1px solid var(--border);
  overflow: hidden;
  position: relative;
  display: flex;
}

.preview-scroll {
  width: 100%;
  height: 100%;
  overflow: auto;
  position: relative;
  padding: 70px 24px 24px;
  display: flex;
  align-items: flex-start;
  justify-content: center;
}

.preview-panel.is-empty .preview-scroll {
  display: none;
}

.canvas-stage {
  position: relative;
  flex: none;
  margin: auto;
}

/* Add Images button (single element, position/size depend on empty state) */

.add-images-btn {
  position: absolute;
  z-index: 50;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  font-family: inherit;
  font-weight: 600;
  color: #fff;
  background: var(--accent);
  border: none;
  border-radius: var(--radius);
  cursor: pointer;
  box-shadow: var(--shadow-md);
  transition: background 0.15s ease, transform 0.1s ease;
}

.add-images-btn:hover {
  background: var(--accent-dark);
}

.add-images-btn:active {
  transform: scale(0.98);
}

.add-images-btn .add-icon {
  font-size: 1.3em;
  line-height: 1;
}

.preview-panel.is-empty .add-images-btn {
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  font-size: 18px;
  padding: 22px 36px;
}

.preview-panel:not(.is-empty) .add-images-btn {
  top: 16px;
  left: 16px;
  font-size: 13px;
  padding: 9px 16px;
}

/* Clear All button — sits next to the compact Add Images button, only
   ever shown once images exist. */

.clear-all-btn {
  position: absolute;
  z-index: 50;
  top: 16px;
  left: 145px;
  font-family: inherit;
  font-weight: 600;
  font-size: 13px;
  color: var(--text-muted);
  background: var(--panel-bg);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 9px 16px;
  cursor: pointer;
  box-shadow: var(--shadow-sm);
  transition: background 0.15s ease, color 0.15s ease, transform 0.1s ease;
}

.clear-all-btn:hover {
  background: #fef2f2;
  color: #dc2626;
  border-color: #fecaca;
}

.clear-all-btn:active {
  transform: scale(0.97);
}

.preview-panel.is-empty .clear-all-btn {
  display: none;
}

/* drag-over highlight when dragging files from OS */
.preview-panel.drag-over::after {
  content: "";
  position: absolute;
  inset: 8px;
  border: 2px dashed var(--accent);
  border-radius: var(--radius-sm);
  background: rgba(37, 99, 235, 0.06);
  pointer-events: none;
  z-index: 40;
}

/* ================= IMAGE ITEMS ================= */

.image-item {
  position: absolute;
  overflow: hidden;
  cursor: grab;
  background: #f3f4f6;
  outline: 2px solid transparent;
  outline-offset: 2px;
  transition: outline-color 0.12s ease;
}

.image-item.selected {
  outline-color: var(--accent);
}

.image-item.drag-source {
  opacity: 0.4;
}

.image-item.drop-target {
  outline-color: #16a34a;
  outline-style: dashed;
}

.rotator {
  position: absolute;
  top: 50%;
  left: 50%;
}

.rotator img {
  display: block;
  width: 100%;
  height: 100%;
  user-select: none;
  -webkit-user-drag: none;
  pointer-events: none;
}

.item-toolbar {
  position: absolute;
  top: 6px;
  right: 6px;
  display: flex;
  gap: 4px;
  background: rgba(20, 24, 33, 0.72);
  border-radius: 8px;
  padding: 4px;
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.12s ease;
  z-index: 5;
}

.image-item:hover .item-toolbar,
.image-item.selected .item-toolbar {
  opacity: 1;
  pointer-events: auto;
}

.toolbar-btn {
  width: 26px;
  height: 26px;
  display: flex;
  align-items: center;
  justify-content: center;
  border: none;
  border-radius: 5px;
  background: transparent;
  color: #fff;
  cursor: pointer;
  font-size: 14px;
  line-height: 1;
}

.toolbar-btn:hover {
  background: rgba(255, 255, 255, 0.2);
}

.toolbar-btn.danger:hover {
  background: #dc2626;
}

/* ================= CONTROLS PANEL ================= */

.controls-panel {
  flex: 3 1 0;
  min-width: 260px;
  max-width: 380px;
  background: var(--panel-bg);
  border-radius: var(--radius);
  box-shadow: var(--shadow-sm);
  border: 1px solid var(--border);
  overflow: hidden;
  display: flex;
}

.controls-scroll {
  flex: 1;
  overflow-y: auto;
  padding: 18px;
  display: flex;
  flex-direction: column;
  gap: 20px;
}

.control-section {
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.control-section[hidden] {
  display: none;
}

.control-title {
  font-size: 12px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--text-muted);
  margin: 0;
}

/* Segmented control */

.segmented {
  display: flex;
  background: #f1f3f7;
  border-radius: var(--radius-sm);
  padding: 3px;
  gap: 2px;
}

.segmented-btn {
  flex: 1;
  border: none;
  background: transparent;
  padding: 8px 6px;
  border-radius: 6px;
  font-family: inherit;
  font-size: 13px;
  font-weight: 600;
  color: var(--text-muted);
  cursor: pointer;
  transition: background 0.12s ease, color 0.12s ease;
}

.segmented-btn:hover {
  color: var(--text);
}

.segmented-btn.active {
  background: #fff;
  color: var(--accent);
  box-shadow: var(--shadow-sm);
}

/* Radio pills */

.radio-row {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.radio-pill {
  display: flex;
  align-items: center;
  gap: 6px;
  font-size: 13px;
  font-weight: 500;
  padding: 7px 12px;
  border-radius: 999px;
  background: #f1f3f7;
  cursor: pointer;
  user-select: none;
  transition: background 0.12s ease, color 0.12s ease;
}

.radio-pill input {
  accent-color: var(--accent);
  margin: 0;
}

.radio-pill:has(input:checked) {
  background: var(--accent-light);
  color: var(--accent-dark);
}

/* Field rows */

.field-row {
  display: flex;
  align-items: center;
  gap: 10px;
}

.field-row[hidden] {
  display: none;
}

.field-row label {
  font-size: 13px;
  color: var(--text-muted);
  flex: none;
}

.field-row input[type="number"] {
  width: 70px;
  padding: 7px 9px;
  border-radius: var(--radius-sm);
  border: 1px solid var(--border);
  font-family: inherit;
  font-size: 13px;
}

.field-row input[type="range"] {
  flex: 1;
  accent-color: var(--accent);
}

.field-row input[type="color"] {
  width: 40px;
  height: 30px;
  padding: 0;
  border: 1px solid var(--border);
  border-radius: 6px;
  cursor: pointer;
  background: none;
}

.output-size-readout {
  font-size: 13px;
  font-weight: 600;
  color: var(--text);
  background: #f1f3f7;
  border-radius: var(--radius-sm);
  padding: 8px 10px;
}

.select-input {
  width: 100%;
  padding: 8px 10px;
  border-radius: var(--radius-sm);
  border: 1px solid var(--border);
  font-family: inherit;
  font-size: 13px;
  background: #fff;
  cursor: pointer;
}

#customSizeRow input[type="number"] {
  width: 0;
  flex: 1;
}

.size-x {
  color: var(--text-muted);
  font-size: 12px;
  flex: none;
}

.gap-value {
  font-size: 12px;
  color: var(--text-muted);
  width: 42px;
  text-align: right;
  flex: none;
}

/* Buttons */

.btn {
  font-family: inherit;
  font-size: 13px;
  font-weight: 600;
  padding: 10px 14px;
  border-radius: var(--radius-sm);
  border: none;
  cursor: pointer;
  transition: background 0.12s ease, transform 0.1s ease;
}

.btn:active {
  transform: scale(0.97);
}

.btn-primary {
  background: var(--accent);
  color: #fff;
  flex: 1;
}

.btn-primary:hover {
  background: var(--accent-dark);
}

.export-row {
  display: flex;
  gap: 8px;
}

/* ================= STATUS BAR ================= */

.status-bar {
  flex: none;
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 8px 20px;
  font-size: 12.5px;
  color: var(--text-muted);
  background: var(--panel-bg);
  border-top: 1px solid var(--border);
}

.status-sep {
  opacity: 0.5;
}

/* ================= RESPONSIVE ================= */

@media (max-width: 860px) {
  .main-layout {
    flex-direction: column;
  }

  .preview-panel {
    flex: none;
    height: 55vh;
  }

  .controls-panel {
    flex: none;
    max-width: none;
    height: 40vh;
  }
}