:root {
  --bg-main: #f4f6f5;
  --bg-soft: #e8efed;
  --surface: #ffffff;
  --surface-muted: #f2f6f5;
  --text-main: #1d2a28;
  --text-muted: #546865;
  --accent: #0f7668;
  --accent-strong: #0a5a50;
  --accent-soft: #d7ebe7;
  --border: #d8e3e0;
  --shadow: 0 18px 40px rgba(18, 39, 36, 0.08);
  --radius-lg: 18px;
  --radius-md: 12px;
}

* {
  box-sizing: border-box;
}

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

body {
  font-family: "Source Sans 3", "Segoe UI", sans-serif;
  color: var(--text-main);
  background: var(--bg-main);
  line-height: 1.45;
}

.page-background {
  position: fixed;
  inset: 0;
  z-index: -1;
  background:
    radial-gradient(circle at 10% -5%, #ffffff 0%, rgba(255, 255, 255, 0) 50%),
    radial-gradient(
      circle at 90% 0%,
      rgba(14, 128, 112, 0.12) 0%,
      rgba(14, 128, 112, 0) 40%
    ),
    linear-gradient(180deg, var(--bg-main) 0%, var(--bg-soft) 100%);
}

.app-shell {
  width: min(1200px, 100% - 2rem);
  margin: 0 auto;
  padding: clamp(1.4rem, 2.2vw, 2rem) 0 2.2rem;
  display: grid;
  gap: 1rem;
}

.hero-block {
  display: grid;
  gap: 0.25rem;
  padding: 0.25rem;
}

.kicker {
  margin: 0;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  font-size: 0.78rem;
  font-weight: 700;
  color: var(--accent-strong);
}

.hero-block h1 {
  margin: 0;
  font-family: "Sora", "Trebuchet MS", sans-serif;
  font-size: clamp(1.7rem, 3vw, 2.5rem);
  line-height: 1.1;
}

.lead {
  margin: 0;
  max-width: 65ch;
  color: var(--text-muted);
  font-size: 1.03rem;
}

.card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow);
  padding: 1rem;
  animation: rise-in 0.55s ease both;
}

.toolbar {
  display: grid;
  gap: 0.7rem;
}

.toolbar-left,
.toolbar-right {
  display: flex;
  gap: 0.75rem;
  align-items: center;
  flex-wrap: wrap;
}

.toolbar {
  grid-template-columns: 1fr auto;
  align-items: start;
}

.button-group {
  display: inline-grid;
  grid-auto-flow: column;
  gap: 0.2rem;
  background: var(--surface-muted);
  padding: 0.2rem;
  border-radius: 999px;
  border: 1px solid var(--border);
}

button,
select,
input {
  font: inherit;
}

.mode-button {
  border: 0;
  border-radius: 999px;
  background: transparent;
  color: var(--text-muted);
  padding: 0.45rem 0.85rem;
  font-weight: 700;
  cursor: pointer;
  transition:
    background-color 0.18s ease,
    color 0.18s ease;
}

.mode-button:hover {
  background: #e4f0ed;
  color: var(--text-main);
}

.mode-button.is-active {
  background: var(--accent-soft);
  color: var(--accent-strong);
}

.toggle-field {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  color: var(--text-main);
  font-weight: 600;
  cursor: pointer;
}

.toggle-field input {
  accent-color: var(--accent);
}

.button-secondary,
.button-ghost {
  border-radius: 10px;
  padding: 0.48rem 0.75rem;
  font-weight: 600;
  cursor: pointer;
}

.button-secondary {
  border: 1px solid var(--accent);
  background: var(--accent);
  color: #f6fffd;
  transition: background-color 0.2s ease;
}

.button-secondary:hover {
  background: var(--accent-strong);
}

.button-ghost {
  border: 1px solid var(--border);
  background: var(--surface-muted);
  color: var(--text-main);
  transition:
    border-color 0.2s ease,
    background-color 0.2s ease;
}

.button-ghost:hover {
  border-color: #bdd1cc;
  background: #edf4f2;
}

.status-message {
  margin: 0;
  min-height: 1.2em;
  color: var(--text-muted);
  font-size: 0.95rem;
  grid-column: 1 / -1;
}

.status-message.is-error {
  color: #9a2f2f;
}

.controls-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1rem;
}

.panel-controls {
  display: grid;
  gap: 0.85rem;
}

.panel-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 0.8rem;
}

.panel-header h2 {
  margin: 0;
  font-family: "Sora", "Trebuchet MS", sans-serif;
  font-size: 1.1rem;
}

.field-grid {
  display: grid;
  grid-template-columns: auto 1fr;
  align-items: center;
  gap: 0.6rem 0.9rem;
}

.field-grid label {
  color: var(--text-muted);
  font-weight: 600;
}

select {
  width: 100%;
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  background: #fbfdfc;
  padding: 0.5rem 0.7rem;
  color: var(--text-main);
}

select:focus,
button:focus-visible {
  outline: 2px solid #65a79d;
  outline-offset: 2px;
}

.viewer-stack {
  display: grid;
  gap: 1rem;
}

.comparison-view {
  display: grid;
  gap: 0.8rem;
}

.filename {
  color: var(--text-muted);
  font-size: 0.92rem;
  font-family: "Iosevka Term", "Consolas", "SFMono-Regular", monospace;
  word-break: break-all;
}

.split-view {
  display: grid;
  gap: 0.8rem;
}

.overlay-view {
  display: grid;
  gap: 0.8rem;
}

.is-hidden {
  display: none !important;
}

.split-view.is-hidden {
  display: none;
}

.overlay-stage,
.split-stage {
  position: relative;
  border-radius: var(--radius-md);
  overflow: hidden;
  border: 1px solid var(--border);
  background: #f4f8f7;
  touch-action: none;
}

.overlay-stage > img,
.split-stage > img {
  width: 100%;
  user-select: none;
  -webkit-user-drag: none;
  display: block;
}

.corner-badge {
  position: absolute;
  top: 0.75rem;
  z-index: 4;
  display: inline-flex;
  align-items: center;
  padding: 0.3rem 0.55rem;
  border-radius: 999px;
  border: 1px solid rgba(255, 255, 255, 0.6);
  font-size: 0.78rem;
  font-weight: 700;
  color: #f4fffd;
  background: rgba(20, 45, 41, 0.78);
  letter-spacing: 0.02em;
  backdrop-filter: blur(3px);
  pointer-events: none;
}

.corner-badge-left {
  left: 0.75rem;
}

.corner-badge-right {
  right: 0.75rem;
}

.corner-badge.is-image-a {
  background: rgba(29, 65, 118, 0.78);
}

.corner-badge.is-image-b {
  background: rgba(11, 102, 80, 0.78);
}

.layer-top,
.split-overlay-image {
  position: absolute;
  inset: 0;
  height: 100%;
  object-fit: contain;
}

.layer-top {
  cursor: pointer;
  transition: opacity 0.14s ease;
}

.layer-top.is-layer-hidden {
  opacity: 0;
}

.split-stage {
  cursor: col-resize;
}

.split-overlay-image {
  clip-path: inset(0 50% 0 0);
  pointer-events: none;
}

.split-stage > img {
  pointer-events: none;
}

.split-divider {
  position: absolute;
  top: 0;
  bottom: 0;
  left: 50%;
  width: 2px;
  background: var(--accent-strong);
  transform: translateX(-50%);
  pointer-events: none;
}

.split-divider::after {
  content: "";
  position: absolute;
  top: 50%;
  left: 50%;
  width: 14px;
  height: 14px;
  border: 2px solid var(--accent-strong);
  border-radius: 50%;
  background: #f8fffd;
  transform: translate(-50%, -50%);
}

.interaction-hint {
  margin: 0;
  color: var(--text-muted);
  font-size: 0.94rem;
}

.view-state {
  margin: 0;
  padding: 0.45rem 0.6rem;
  border-radius: 10px;
  background: var(--surface-muted);
  border: 1px solid var(--border);
  color: var(--text-main);
  font-weight: 600;
  font-size: 0.92rem;
}

.legend-row,
.file-row {
  margin: 0;
  display: flex;
  justify-content: space-between;
  gap: 1rem;
}

.legend-row {
  color: var(--text-muted);
  font-weight: 600;
}

.file-row {
  align-items: flex-start;
}

.file-row .filename {
  flex: 1;
  min-width: 0;
}

@keyframes rise-in {
  from {
    opacity: 0;
    transform: translateY(12px);
  }

  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@media (max-width: 960px) {
  .toolbar {
    grid-template-columns: 1fr;
  }

  .controls-grid {
    grid-template-columns: 1fr;
  }

  .legend-row,
  .file-row {
    flex-direction: column;
  }
}

@media (max-width: 620px) {
  .app-shell {
    width: min(100% - 1rem, 1200px);
  }

  .field-grid {
    grid-template-columns: 1fr;
    gap: 0.45rem;
  }

  .field-grid label {
    margin-top: 0.25rem;
  }

  .button-group {
    width: 100%;
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

@media (prefers-reduced-motion: reduce) {
  .card,
  .mode-button,
  .button-secondary,
  .button-ghost {
    animation: none;
    transition: none;
  }
}