:root {
  /* Light Studio palette — inverted from Nocturnal Precision */
  --surface:                #ffffff;
  --surface-container-low:  #f7f8fa;
  --surface-container:      #f1f3f6;
  --surface-container-high: #e8ecf0;
  --surface-container-highest: #dfe4ea;
  --surface-bright:         #d6dbe1;

  --on-surface:             #0f1419;
  --on-surface-variant:     #424656;
  --on-surface-muted:       #6b7280;

  --primary:                #4f8cff;
  --primary-container:      #0066ff;
  --on-primary:             #ffffff;

  --primary-tint:           rgba(79, 140, 255, 0.08);
  --primary-tint-strong:    rgba(79, 140, 255, 0.18);

  --success:                #22b45c;
  --danger:                 #e5484d;
  --warn:                   #e08a00;
  --tertiary:               #ff8560;

  --outline-variant:        rgba(15, 20, 25, 0.1);

  --radius-sm:  0.5rem;
  --radius-md:  0.75rem;
  --radius-lg:  1rem;
  --radius-xl:  1.5rem;
  --radius-full: 9999px;

  --shadow-ambient: 0 2px 8px rgba(15, 20, 25, 0.04), 0 16px 40px rgba(15, 20, 25, 0.05);
  --shadow-floating: 0 12px 32px rgba(15, 20, 25, 0.15);

  --font-display: 'Manrope', -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  --font-body:    'Inter', -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
}

* {
  box-sizing: border-box;
}

html, body {
  margin: 0;
  padding: 0;
  background: var(--surface);
  color: var(--on-surface);
  font-family: var(--font-body);
  font-size: 15px;
  line-height: 1.5;
  min-height: 100vh;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

h1, h2, h3, h4 {
  font-family: var(--font-display);
  letter-spacing: -0.02em;
  font-weight: 700;
  margin: 0;
}

/* ========================================================================
   HEADER + STEPPER
   ======================================================================== */

header {
  display: grid;
  grid-template-columns: 1fr auto 1fr;
  align-items: center;
  padding: 18px 32px;
  gap: 24px;
  background: var(--surface-container-low);
}

header h1 {
  font-size: 20px;
  font-weight: 800;
  letter-spacing: -0.01em;
  justify-self: start;
}

.stepper {
  display: flex;
  align-items: center;
  gap: 0;
  justify-self: center;
}

.step-node {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 6px 12px;
  border-radius: var(--radius-full);
  color: var(--on-surface-muted);
  transition: color 0.15s;
}

.step-node .num {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 28px;
  height: 28px;
  border-radius: var(--radius-full);
  background: var(--surface-container-high);
  color: var(--on-surface-muted);
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 13px;
  transition: background 0.15s, color 0.15s;
}

.step-node .label {
  font-family: var(--font-display);
  font-weight: 600;
  font-size: 14px;
  letter-spacing: -0.01em;
}

.step-node.active {
  color: var(--on-surface);
}

.step-node.active .num {
  background: linear-gradient(135deg, var(--primary), var(--primary-container));
  color: var(--on-primary);
  box-shadow: 0 0 0 4px var(--primary-tint-strong);
}

.step-node.complete .num {
  background: var(--primary-container);
  color: white;
}

.step-connector {
  width: 40px;
  height: 2px;
  background: var(--surface-container-high);
  margin: 0 4px;
}

.step-node.complete + .step-connector {
  background: var(--primary-container);
}

.lang-toggle {
  justify-self: end;
  display: flex;
  gap: 4px;
}

.lang-toggle button {
  background: transparent;
  color: var(--on-surface-muted);
  border: 1px solid var(--outline-variant);
  border-radius: var(--radius-sm);
  padding: 5px 12px;
  font-family: var(--font-body);
  font-size: 12px;
  font-weight: 600;
  cursor: pointer;
  letter-spacing: 0.02em;
}

.lang-toggle button.active {
  color: var(--on-surface);
  background: var(--primary-tint);
  border-color: rgba(79, 140, 255, 0.4);
}

/* ========================================================================
   MAIN / STEPS
   ======================================================================== */

main {
  max-width: 1400px;
  margin: 0 auto;
  padding: 32px;
}

.step {
  display: none;
}

.step.active {
  display: block;
}

h2 {
  font-size: 22px;
  margin: 0 0 20px 0;
  letter-spacing: -0.02em;
}

/* ========================================================================
   SPLIT LAYOUT (upload step)
   ======================================================================== */

.split {
  display: grid;
  grid-template-columns: 1.5fr 1fr;
  gap: 24px;
  align-items: start;
}

.workspace {
  min-height: 520px;
}

.config-panel {
  background: var(--surface-container);
  border-radius: var(--radius-xl);
  padding: 24px;
  display: flex;
  flex-direction: column;
  gap: 18px;
  box-shadow: var(--shadow-ambient);
}

.config-panel h2 {
  font-size: 16px;
  font-weight: 700;
  text-transform: none;
  letter-spacing: -0.01em;
  margin-bottom: 4px;
}

@media (max-width: 900px) {
  .split {
    grid-template-columns: 1fr;
  }
}

/* ========================================================================
   DROPZONE
   ======================================================================== */

.dropzone {
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--surface-container-low);
  border-radius: var(--radius-xl);
  padding: 80px 32px;
  cursor: pointer;
  min-height: 520px;
  transition: background 0.15s, transform 0.15s;
}

.dropzone:hover,
.dropzone.dragover {
  background: var(--surface-container);
}

.dropzone-inner {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 10px;
  text-align: center;
}

.dropzone-icon {
  width: 64px;
  height: 64px;
  border-radius: var(--radius-full);
  background: var(--primary-tint);
  color: var(--primary);
  display: inline-flex;
  align-items: center;
  justify-content: center;
  font-size: 28px;
  margin-bottom: 12px;
}

.dropzone-inner strong {
  font-family: var(--font-display);
  font-size: 20px;
  font-weight: 700;
  letter-spacing: -0.01em;
  color: var(--on-surface);
}

.dropzone-inner span {
  color: var(--on-surface-variant);
  font-size: 14px;
}

/* ========================================================================
   CONFIG PANEL — FIELDS
   ======================================================================== */

.field {
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.field-label {
  font-family: var(--font-body);
  font-size: 12px;
  font-weight: 500;
  color: var(--on-surface-variant);
  text-transform: uppercase;
  letter-spacing: 0.08em;
}

select,
input[type="file"],
input[type="text"] {
  background: var(--surface-container-low);
  border: none;
  color: var(--on-surface);
  border-radius: var(--radius-md);
  padding: 10px 12px;
  font-family: var(--font-body);
  font-size: 14px;
  outline: none;
  transition: box-shadow 0.15s;
}

input[type="text"]:focus {
  box-shadow: 0 0 0 2px rgba(79, 140, 255, 0.35);
}

input[type="text"].invalid {
  box-shadow: 0 0 0 2px rgba(255, 90, 95, 0.4);
}

.input-with-button {
  display: flex;
  gap: 6px;
  align-items: stretch;
}

.input-with-button input[type="text"] {
  flex: 1;
}

.input-with-button button {
  padding: 10px 14px;
  background: var(--surface-container-high);
  border: none;
  border-radius: var(--radius-md);
  color: var(--on-surface);
  font-size: 16px;
  cursor: pointer;
}

.input-with-button button:hover {
  background: var(--surface-container-highest);
}

/* ========================================================================
   BACKDROP TILES
   ======================================================================== */

.backdrop-tiles {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 8px;
}

.backdrop-tile {
  position: relative;
  background: var(--surface-container-low);
  border: 2px solid transparent;
  border-radius: var(--radius-md);
  padding: 0;
  cursor: pointer;
  overflow: hidden;
  display: flex;
  flex-direction: column;
  aspect-ratio: 1.2 / 1;
  transition: transform 0.15s, border-color 0.15s;
}

.backdrop-tile img {
  width: 100%;
  height: 68%;
  object-fit: cover;
  display: block;
  background: var(--surface-container);
}

.backdrop-tile span {
  flex: 1;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 4px 8px;
  font-family: var(--font-body);
  font-size: 11px;
  font-weight: 500;
  color: var(--on-surface-variant);
  letter-spacing: 0.01em;
  text-align: center;
  line-height: 1.2;
}

.backdrop-tile:hover {
  transform: translateY(-1px);
}

.backdrop-tile.active {
  border-color: var(--primary);
  box-shadow: 0 0 0 4px var(--primary-tint-strong);
}

.backdrop-tile.active span {
  color: var(--on-surface);
}

/* ========================================================================
   BUTTONS
   ======================================================================== */

button {
  font-family: var(--font-body);
  cursor: pointer;
  border: none;
}

button.primary {
  background: var(--surface-container-high);
  color: var(--on-surface);
  border-radius: var(--radius-full);
  padding: 14px 24px;
  font-family: var(--font-display);
  font-size: 14px;
  font-weight: 700;
  letter-spacing: 0.02em;
  text-transform: uppercase;
  transition: transform 0.15s, box-shadow 0.15s, opacity 0.15s;
}

button.primary.gradient {
  background: linear-gradient(135deg, var(--primary), var(--primary-container));
  color: var(--on-primary);
  box-shadow: inset 0 1px 0 rgba(255, 255, 255, 0.25), 0 8px 20px rgba(0, 102, 255, 0.22);
}

button.primary:hover:not(:disabled) {
  transform: translateY(-1px);
}

button.primary:disabled {
  opacity: 0.4;
  cursor: not-allowed;
}

button.primary small {
  margin-left: 8px;
  opacity: 0.85;
  font-weight: 500;
  font-family: var(--font-body);
  text-transform: none;
  letter-spacing: 0;
}

/* ========================================================================
   PRO TIP
   ======================================================================== */

.pro-tip {
  background: var(--surface-container-low);
  border-radius: var(--radius-md);
  padding: 14px 16px;
  display: flex;
  flex-direction: column;
  gap: 8px;
  margin-top: 4px;
}

.pro-tip-header {
  display: flex;
  align-items: center;
  gap: 8px;
  font-family: var(--font-display);
  font-size: 12px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--on-surface-variant);
}

.pro-tip-icon {
  width: 22px;
  height: 22px;
  border-radius: var(--radius-full);
  background: rgba(255, 181, 157, 0.15);
  color: var(--tertiary);
  display: inline-flex;
  align-items: center;
  justify-content: center;
  font-size: 12px;
}

.pro-tip p {
  margin: 0;
  font-size: 13px;
  color: var(--on-surface-variant);
  line-height: 1.5;
}

/* ========================================================================
   PROGRESS STEP
   ======================================================================== */

progress {
  width: 100%;
  height: 6px;
  border: none;
  border-radius: var(--radius-full);
  overflow: hidden;
  background: var(--surface-container);
}

progress::-webkit-progress-bar {
  background: var(--surface-container);
}

progress::-webkit-progress-value {
  background: linear-gradient(90deg, var(--primary), var(--primary-container));
}

progress::-moz-progress-bar {
  background: linear-gradient(90deg, var(--primary), var(--primary-container));
}

.muted {
  color: var(--on-surface-muted);
  font-size: 13px;
}

.warn {
  background: rgba(255, 176, 32, 0.1);
  color: var(--warn);
  padding: 14px 18px;
  border-radius: var(--radius-md);
  font-size: 14px;
  line-height: 1.5;
}

.photo-list {
  list-style: none;
  padding: 0;
  margin: 20px 0;
  display: grid;
  gap: 10px;
}

.photo-list li {
  display: flex;
  justify-content: space-between;
  align-items: center;
  background: var(--surface-container);
  padding: 12px 16px;
  border-radius: var(--radius-md);
  font-size: 14px;
}

.photo-list .status {
  font-family: var(--font-display);
  font-size: 11px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  padding: 4px 10px;
  border-radius: var(--radius-full);
  background: var(--surface-container-high);
}

.photo-list .status.ok {
  background: rgba(52, 199, 89, 0.15);
  color: var(--success);
}

.photo-list .status.err {
  background: rgba(255, 90, 95, 0.15);
  color: var(--danger);
}

/* ========================================================================
   REVIEW STEP
   ======================================================================== */

.review-list {
  list-style: none;
  padding: 0;
  margin: 20px 0;
  display: grid;
  gap: 20px;
}

.review-list li {
  background: var(--surface-container);
  border-radius: var(--radius-xl);
  padding: 20px;
  box-shadow: var(--shadow-ambient);
}

.review-pair {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 20px;
  margin-bottom: 16px;
}

.review-pair figure {
  margin: 0;
}

.review-pair figcaption {
  font-family: var(--font-body);
  font-size: 11px;
  font-weight: 500;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--on-surface-muted);
  margin-bottom: 8px;
}

.review-pair img {
  width: 100%;
  height: auto;
  border-radius: var(--radius-md);
  display: block;
}

.review-actions {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
  align-items: center;
}

.review-actions label {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 13px;
  flex: 1 1 auto;
  color: var(--on-surface-variant);
}

.review-actions button {
  padding: 10px 16px;
  font-size: 13px;
  font-family: var(--font-display);
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.04em;
  border-radius: var(--radius-full);
  cursor: pointer;
}

.review-actions button.approve {
  background: var(--success);
  color: var(--surface);
}

.review-actions button.regenerate {
  background: var(--surface-container-high);
  color: var(--on-surface);
}

.review-actions button.reject {
  background: transparent;
  color: var(--danger);
  box-shadow: inset 0 0 0 1px rgba(255, 90, 95, 0.4);
}

.review-footer {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-top: 20px;
  padding-top: 20px;
  gap: 16px;
}

.review-footer .primary {
  margin-top: 0;
}

/* ========================================================================
   FOOTER
   ======================================================================== */

footer {
  text-align: center;
  padding: 24px;
  color: var(--on-surface-muted);
  font-size: 12px;
  margin-top: 40px;
}

footer a {
  color: var(--primary);
}

/* ========================================================================
   TOASTS
   ======================================================================== */

#toast-container {
  position: fixed;
  bottom: 20px;
  right: 20px;
  display: flex;
  flex-direction: column;
  gap: 8px;
  z-index: 1000;
}

.toast {
  background: var(--surface-container-highest);
  color: var(--on-surface);
  padding: 12px 16px;
  border-radius: var(--radius-md);
  font-size: 14px;
  min-width: 260px;
  box-shadow: var(--shadow-floating);
  box-shadow: inset 3px 0 0 var(--primary), var(--shadow-floating);
  animation: slide-in 0.2s ease-out;
}

.toast.err {
  box-shadow: inset 3px 0 0 var(--danger), var(--shadow-floating);
}

.toast.warn {
  box-shadow: inset 3px 0 0 var(--warn), var(--shadow-floating);
}

@keyframes slide-in {
  from {
    opacity: 0;
    transform: translateX(20px);
  }
  to {
    opacity: 1;
    transform: translateX(0);
  }
}

/* ========================================================================
   MODAL (VIN scan)
   ======================================================================== */

.modal {
  position: fixed;
  inset: 0;
  background: rgba(0, 0, 0, 0.75);
  backdrop-filter: blur(8px);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 2000;
}

.modal[hidden] {
  display: none;
}

.modal-content {
  background: var(--surface-container-highest);
  border-radius: var(--radius-xl);
  padding: 24px;
  max-width: 560px;
  width: 92vw;
  display: flex;
  flex-direction: column;
  gap: 16px;
  box-shadow: var(--shadow-floating);
}

.modal-content h3 {
  font-size: 16px;
}

.modal-content video {
  width: 100%;
  max-height: 60vh;
  background: #000;
  border-radius: var(--radius-md);
  object-fit: cover;
}

.modal-footer {
  display: flex;
  justify-content: flex-end;
}

.modal-footer button {
  background: var(--surface-container-high);
  color: var(--on-surface);
  padding: 10px 20px;
  border-radius: var(--radius-full);
  font-family: var(--font-display);
  font-weight: 600;
  font-size: 13px;
  cursor: pointer;
}

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

@media (max-width: 900px) {
  header {
    grid-template-columns: 1fr;
    text-align: center;
    gap: 12px;
  }

  header h1,
  .stepper,
  .lang-toggle {
    justify-self: center;
  }

  .stepper {
    flex-wrap: wrap;
  }

  main {
    padding: 20px 16px;
  }

  .review-pair {
    grid-template-columns: 1fr;
  }

  .backdrop-tiles {
    grid-template-columns: repeat(3, 1fr);
  }
}