:root {
  --ink: #1e3a5f;
  --ink-deep: #122238;
  --ink-soft: #6b6b62;
  --parchment: #faf8f0;
  --parchment-deep: #efe9d8;
  --parchment-line: #ddd6c0;
  --verdigris: #4c7a6f;
  --verdigris-deep: #375a52;
  --brick: #a6392f;
  --brick-bg: #f5e6e3;
  --forest: #3f6b4f;
  --forest-bg: #e5eee6;
  --radius: 3px;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  background: var(--parchment);
  color: var(--ink-deep);
  font-family: "IBM Plex Sans", sans-serif;
  line-height: 1.5;
}

.wrap {
  max-width: 760px;
  margin: 0 auto;
  padding: 48px 24px 96px;
}

header.page-head {
  margin-bottom: 40px;
}

.eyebrow {
  font-family: "IBM Plex Mono", monospace;
  font-size: 12px;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--verdigris-deep);
  margin: 0 0 10px;
}

h1 {
  font-family: "Fraunces", serif;
  font-optical-sizing: auto;
  font-weight: 600;
  font-size: clamp(28px, 5vw, 38px);
  margin: 0 0 8px;
  color: var(--ink);
  letter-spacing: -0.01em;
}

.subhead {
  color: var(--ink-soft);
  font-size: 15px;
  max-width: 56ch;
  margin: 0;
}

/* --- Segmented tab --- */
.tabs {
  display: inline-flex;
  border: 1px solid var(--ink);
  border-radius: var(--radius);
  overflow: hidden;
  margin-bottom: 28px;
}
.tab-btn {
  font-family: "IBM Plex Sans", sans-serif;
  font-size: 14px;
  font-weight: 500;
  padding: 10px 22px;
  background: var(--parchment);
  color: var(--ink);
  border: none;
  cursor: pointer;
  transition:
    background 0.15s ease,
    color 0.15s ease;
}
.tab-btn + .tab-btn {
  border-left: 1px solid var(--ink);
}
.tab-btn[aria-selected="true"] {
  background: var(--ink);
  color: var(--parchment);
}
.tab-btn:focus-visible {
  outline: 2px solid var(--verdigris);
  outline-offset: -2px;
}

.panel {
  display: none;
}
.panel.active {
  display: block;
}

/* --- Card --- */
.card {
  background: #fff;
  border: 1px solid var(--parchment-line);
  border-radius: var(--radius);
  padding: 28px;
}

.field {
  margin-bottom: 18px;
}
.field label {
  display: block;
  font-size: 13px;
  font-weight: 500;
  color: var(--ink);
  margin-bottom: 6px;
}
.field input,
.field select {
  width: 100%;
  padding: 10px 12px;
  font-family: "IBM Plex Sans", sans-serif;
  font-size: 14px;
  border: 1px solid var(--parchment-line);
  border-radius: var(--radius);
  background: var(--parchment);
  color: var(--ink-deep);
}
.field input:focus,
.field select:focus {
  outline: 2px solid var(--verdigris);
  outline-offset: 1px;
  border-color: var(--verdigris);
}

.btn {
  font-family: "IBM Plex Sans", sans-serif;
  font-size: 14px;
  font-weight: 600;
  padding: 11px 22px;
  background: var(--verdigris);
  color: #fff;
  border: none;
  border-radius: var(--radius);
  cursor: pointer;
  transition: background 0.15s ease;
}
.btn:hover {
  background: var(--verdigris-deep);
}
.btn:disabled {
  background: #b7b7ad;
  cursor: not-allowed;
}
.btn:focus-visible {
  outline: 2px solid var(--ink);
  outline-offset: 2px;
}

.btn-ghost {
  background: transparent;
  color: var(--ink);
  border: 1px solid var(--ink);
}
.btn-ghost:hover {
  background: var(--parchment-deep);
}

/* --- Dropzone --- */
.dropzone {
  border: 1.5px dashed var(--parchment-line);
  border-radius: var(--radius);
  padding: 32px 20px;
  text-align: center;
  cursor: pointer;
  color: var(--ink-soft);
  font-size: 14px;
  transition:
    border-color 0.15s ease,
    background 0.15s ease;
}
.dropzone:hover,
.dropzone.drag-over {
  border-color: var(--verdigris);
  background: var(--parchment);
}
.dropzone input {
  display: none;
}

/* --- Preview with LSB overlay --- */
.preview-wrap {
  position: relative;
  display: inline-block;
  margin-top: 20px;
  max-width: 100%;
  border: 1px solid var(--parchment-line);
  line-height: 0;
}
.preview-wrap img {
  display: block;
  max-width: 100%;
  height: auto;
}
.lsb-zone {
  position: absolute;
  left: 90%;
  top: 92.85%;
  width: 10%;
  height: 0.85%;
  border: 1.5px dashed var(--verdigris);
  animation: march 0.8s linear infinite;
  pointer-events: none;
}
@keyframes march {
  to {
    border-color: var(--ink);
  }
}
@media (prefers-reduced-motion: reduce) {
  .lsb-zone {
    animation: none;
  }
}
.lsb-callout {
  font-family: "IBM Plex Mono", monospace;
  font-size: 11.5px;
  color: var(--verdigris-deep);
  margin-top: 10px;
  line-height: 1.6;
}

/* --- Result states --- */
.result {
  margin-top: 20px;
  padding: 16px 18px;
  border-radius: var(--radius);
  font-size: 14px;
}
.result.valid {
  background: var(--forest-bg);
  color: var(--forest);
  border: 1px solid var(--forest);
}
.result.invalid {
  background: var(--brick-bg);
  color: var(--brick);
  border: 1px solid var(--brick);
}
.result-title {
  font-weight: 600;
  margin: 0 0 4px;
}
.result-message {
  margin: 0;
  opacity: 0.9;
}

.errors {
  margin-top: 14px;
  padding: 12px 16px;
  background: var(--brick-bg);
  color: var(--brick);
  border: 1px solid var(--brick);
  border-radius: var(--radius);
  font-size: 13px;
}
.errors ul {
  margin: 4px 0 0;
  padding-left: 18px;
}

.actions {
  display: flex;
  gap: 10px;
  margin-top: 18px;
  flex-wrap: wrap;
}

/* --- How it works --- */
.how {
  margin-top: 48px;
  padding-top: 32px;
  border-top: 1px solid var(--parchment-line);
}
.how h2 {
  font-family: "Fraunces", serif;
  font-weight: 600;
  font-size: 20px;
  color: var(--ink);
  margin: 0 0 18px;
}
.steps {
  display: grid;
  gap: 14px;
}
.step {
  display: grid;
  grid-template-columns: 28px 1fr;
  gap: 12px;
}
.step-num {
  font-family: "IBM Plex Mono", monospace;
  font-size: 12px;
  color: var(--verdigris-deep);
  border: 1px solid var(--verdigris);
  border-radius: 50%;
  width: 24px;
  height: 24px;
  display: flex;
  align-items: center;
  justify-content: center;
}
.step-body strong {
  display: block;
  font-size: 14px;
  color: var(--ink);
  margin-bottom: 2px;
}
.step-body span {
  font-size: 13px;
  color: var(--ink-soft);
}

/* --- API config --- */
details.config {
  margin-top: 40px;
  font-size: 13px;
  color: var(--ink-soft);
}
details.config summary {
  cursor: pointer;
  font-family: "IBM Plex Mono", monospace;
  font-size: 12px;
}
details.config .field {
  margin-top: 12px;
  margin-bottom: 0;
}

.spinner {
  display: inline-block;
  width: 14px;
  height: 14px;
  border: 2px solid rgba(255, 255, 255, 0.4);
  border-top-color: #fff;
  border-radius: 50%;
  animation: spin 0.7s linear infinite;
  margin-right: 8px;
  vertical-align: -2px;
}
@keyframes spin {
  to {
    transform: rotate(360deg);
  }
}