:root[data-theme="light"] {
  --bg: #f5f5f5;
  --surface: #ffffff;
  --border: #d0d0d0;
  --text: #222222;
  --text-muted: #555555;
  --accent: #c0392b;
  --accent-hover: #a93226;
  --btn-bg: #c0392b;
  --btn-text: #ffffff;
  --shadow: 0 2px 8px rgba(0, 0, 0, 0.08);
  --badge-bg: #eee;
  --badge-text: #444;
  --legend: #c0392b;
  --input-bg: #ffffff;
  --input-border: #cccccc;
  --border-dashed: #b0b0b0;
}

:root[data-theme="rust"] {
  --bg: #1a1a18;
  --surface: #242320;
  --border: #4a3f35;
  --border-dashed: #5a4a3a;
  --text: #e8dfd0;
  --text-muted: #a89880;
  --accent: #d4631a;
  --accent-hover: #e07730;
  --input-bg: #1e1c1a;
  --input-border: #5a4a3a;
  --btn-bg: #d4631a;
  --btn-text: #fff;
  --badge-bg: #352e28;
  --badge-text: #d4a57a;
  --legend: #d4631a;
  --shadow: 0 2px 12px rgba(0, 0, 0, 0.4);
}

:root[data-theme="coal"] {
  --bg: #111111;
  --surface: #1c1c1c;
  --border: #333333;
  --border-dashed: #444444;
  --text: #e0e0e0;
  --text-muted: #888888;
  --accent: #e0e0e0;
  --accent-hover: #ffffff;
  --input-bg: #181818;
  --input-border: #3a3a3a;
  --btn-bg: #333333;
  --btn-text: #e0e0e0;
  --badge-bg: #252525;
  --badge-text: #aaaaaa;
  --legend: #aaaaaa;
  --shadow: 0 2px 12px rgba(0, 0, 0, 0.6);
}

:root[data-theme="navy"] {
  --bg: #0d1b2a;
  --surface: #112233;
  --border: #1e3a5f;
  --border-dashed: #2a4a70;
  --text: #c8d8e8;
  --text-muted: #7090b0;
  --accent: #3a8fc7;
  --accent-hover: #5aaee0;
  --input-bg: #0a1828;
  --input-border: #1e3a5f;
  --btn-bg: #1a5a9a;
  --btn-text: #e0f0ff;
  --badge-bg: #0f2a44;
  --badge-text: #5aaee0;
  --legend: #5aaee0;
  --shadow: 0 2px 16px rgba(0, 0, 0, 0.5);
}

:root[data-theme="ayu"] {
  --bg: #0f1923;
  --surface: #14202c;
  --border: #253545;
  --border-dashed: #2e4458;
  --text: #cccac2;
  --text-muted: #6b7d8f;
  --accent: #ffb454;
  --accent-hover: #ffc970;
  --input-bg: #0d1820;
  --input-border: #253545;
  --btn-bg: #e6b450;
  --btn-text: #0f1923;
  --badge-bg: #182030;
  --badge-text: #ffb454;
  --legend: #ffb454;
  --shadow: 0 2px 14px rgba(0, 0, 0, 0.5);
}

*,
*::before,
*::after {
  box-sizing: border-box;
}

body {
  font-family: "Segoe UI", system-ui, sans-serif;
  background: var(--bg);
  color: var(--text);
  min-height: 100vh;
  margin: 0;
  padding: 0;
  transition:
    background 0.2s,
    color 0.2s;
}

/* Top bar */
.topbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 1rem 2rem;
  background: var(--surface);
  border-bottom: 1px solid var(--border);
  box-shadow: var(--shadow);
  flex-wrap: wrap;
  gap: 0.75rem;
}

.topbar h1 {
  margin: 0;
  font-size: 1.4rem;
  letter-spacing: 0.02em;
  color: var(--accent);
}

.topbar h1 span {
  color: var(--text);
  font-weight: 400;
}

/* Theme switcher */
.theme-switcher {
  display: flex;
  align-items: center;
  gap: 0.4rem;
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: 999px;
  padding: 0.25rem 0.5rem;
}

.theme-switcher span {
  font-size: 0.72rem;
  color: var(--text-muted);
  padding-right: 0.3rem;
  white-space: nowrap;
}

.theme-btn {
  border: 2px solid transparent;
  border-radius: 50%;
  width: 22px;
  height: 22px;
  cursor: pointer;
  transition:
    transform 0.15s,
    border-color 0.15s;
  padding: 0;
  outline: none;
}

.theme-btn:hover {
  transform: scale(1.2);
}

.theme-btn.active {
  border-color: var(--accent);
  transform: scale(1.15);
}

.theme-btn[data-t="light"] {
  background: #f5f5f5;
}

.theme-btn[data-t="rust"] {
  background: linear-gradient(135deg, #1a1a18 50%, #d4631a 50%);
}

.theme-btn[data-t="coal"] {
  background: #1c1c1c;
}

.theme-btn[data-t="navy"] {
  background: linear-gradient(135deg, #0d1b2a 50%, #3a8fc7 50%);
}

.theme-btn[data-t="ayu"] {
  background: linear-gradient(135deg, #0f1923 50%, #ffb454 50%);
}

/* Main content */
.main {
  max-width: 860px;
  margin: 0 auto;
  padding: 3rem 1.5rem;
}

/* Breadcrumb */
.breadcrumb {
  display: flex;
  align-items: center;
  gap: 0.4rem;
  font-size: 0.8rem;
  color: var(--text-muted);
  margin-bottom: 2rem;
  flex-wrap: wrap;
}

.breadcrumb span {
  color: var(--text-muted);
}

.breadcrumb a {
  color: var(--accent);
  text-decoration: none;
  cursor: pointer;
}

.breadcrumb a:hover {
  text-decoration: underline;
}

.breadcrumb .sep {
  color: var(--border);
}

/* Section heading */
.section-title {
  font-size: 1rem;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.08em;
  margin-bottom: 1.2rem;
  margin-top: 0;
}

/* Button grid */
.btn-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
  gap: 1rem;
  margin-bottom: 2rem;
}

.btn-grid.three {
  grid-template-columns: repeat(auto-fill, minmax(220px, 1fr));
}

.card-btn {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 0.4rem;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 1.4rem 1rem;
  font-size: 0.95rem;
  font-weight: 600;
  color: var(--text);
  cursor: pointer;
  transition:
    border-color 0.15s,
    box-shadow 0.15s,
    transform 0.12s,
    background 0.15s;
  text-align: center;
  letter-spacing: 0.01em;
  box-shadow: var(--shadow);
}

.card-btn:hover {
  border-color: var(--accent);
  box-shadow: 0 4px 20px rgba(0, 0, 0, 0.25);
  transform: translateY(-2px);
  background: var(--input-bg);
}

.card-btn:active {
  transform: translateY(0);
}

.card-btn .icon {
  font-size: 1.8rem;
  line-height: 1;
}

.card-btn .label {
  font-size: 0.9rem;
}

.card-btn .sub {
  font-size: 0.72rem;
  color: var(--text-muted);
  font-weight: 400;
}

.card-btn.accent-btn {
  border-color: var(--accent);
  color: var(--accent);
}

.card-btn.accent-btn:hover {
  background: var(--btn-bg);
  color: var(--btn-text);
}

/* Coming soon toast / inline */
.coming-soon {
  display: none;
  background: var(--surface);
  border: 1px solid var(--border);
  border-left: 4px solid var(--accent);
  border-radius: 8px;
  padding: 1rem 1.2rem;
  margin-top: 1rem;
  color: var(--text-muted);
  font-size: 0.9rem;
}

.coming-soon.show {
  display: block;
}

.coming-soon strong {
  color: var(--accent);
}

/* NF grid - smaller buttons */
.nf-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(120px, 1fr));
  gap: 0.75rem;
  margin-bottom: 2rem;
}

.nf-btn {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 0.8rem 0.5rem;
  font-size: 0.88rem;
  font-weight: 700;
  color: var(--text);
  cursor: pointer;
  text-align: center;
  letter-spacing: 0.03em;
  transition:
    border-color 0.15s,
    background 0.15s,
    transform 0.1s;
  box-shadow: var(--shadow);
}

.nf-btn .nf-sub {
  display: block;
  font-size: 0.65rem;
  font-weight: 400;
  color: var(--text-muted);
  margin-top: 0.2rem;
  letter-spacing: 0;
}

.nf-btn:hover {
  border-color: var(--accent);
  transform: translateY(-2px);
}

.nf-btn:active {
  transform: translateY(0);
}

/* Back button */
.back-btn {
  background: transparent;
  border: 1px solid var(--border);
  color: var(--text-muted);
  border-radius: 6px;
  padding: 0.4rem 0.9rem;
  font-size: 0.82rem;
  cursor: pointer;
  margin-bottom: 1.8rem;
  transition:
    border-color 0.15s,
    color 0.15s;
}

.back-btn:hover {
  border-color: var(--accent);
  color: var(--accent);
}

/* Panels */
.panel {
  display: none;
}

.panel.active {
  display: block;
}

/* Intro subtitle */
.intro {
  text-align: center;
  margin-bottom: 2.5rem;
}

.intro p {
  color: var(--text-muted);
  font-size: 0.95rem;
  margin: 0.4rem 0 0;
}

.nf-logo {
  width: 10rem;
  height: 10rem;
  display: block;
  margin: 0 auto 0.1rem auto;
  object-fit: contain;
}

/* Build Core hint */
.build-core-hint {
  font-size: 0.85rem;
  color: var(--text-muted);
  margin-bottom: 1.5rem;
  margin-top: -0.5rem;
}

.build-core-hint strong {
  color: var(--accent);
}

/* Core NF flow */
.core-nf-flow {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem 0;
  margin-bottom: 2rem;
  align-items: center;
  row-gap: 1rem;
}

.core-flow-item {
  display: flex;
  align-items: center;
  gap: 0;
}

.core-nf-btn {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 0.25rem;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 0.65rem 1rem;
  min-width: 100px;
  max-width: 120px;
  cursor: pointer;
  transition:
    border-color 0.15s,
    background 0.15s,
    transform 0.1s,
    opacity 0.15s;
  box-shadow: var(--shadow);
  text-align: center;
}

.core-nf-btn:hover {
  border-color: var(--accent);
  transform: translateY(-2px);
}

.core-nf-btn:active {
  transform: translateY(0);
}

.core-nf-btn.visited {
  border-color: var(--accent);
  background: var(--input-bg);
}

.core-nf-btn.skipped {
  opacity: 0.45;
  border-style: dashed;
  border-color: var(--border-dashed);
  background: var(--bg);
}

.core-nf-btn.skipped:hover {
  opacity: 0.7;
  border-color: var(--text-muted);
}

.core-nf-name {
  font-size: 0.82rem;
  font-weight: 700;
  color: var(--text);
  letter-spacing: 0.04em;
}

.core-nf-sub {
  font-size: 0.6rem;
  color: var(--text-muted);
  font-weight: 400;
  line-height: 1.2;
  max-width: 90px;
}

.core-nf-badge {
  display: inline-block;
  font-size: 0.58rem;
  font-weight: 600;
  border-radius: 4px;
  padding: 0.1rem 0.3rem;
  margin-top: 0.15rem;
  letter-spacing: 0.02em;
}

.visited-badge {
  background: var(--badge-bg);
  color: var(--accent);
}

.skipped-badge {
  background: var(--badge-bg);
  color: var(--text-muted);
}

.core-flow-arrow {
  font-size: 0.75rem;
  color: var(--border-dashed);
  padding: 0 0.25rem;
  user-select: none;
  line-height: 1;
  opacity: 0.6;
  letter-spacing: -0.05em;
}

/* Core NF config panel */
.core-nf-config-body {
  margin-bottom: 2rem;
}

.core-nf-config-desc {
  color: var(--text-muted);
  font-size: 0.9rem;
  margin-bottom: 1.2rem;
}

.core-nf-config-desc strong {
  color: var(--accent);
}

.core-nf-config-actions {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 0.75rem;
  flex-wrap: wrap;
  margin-top: 1.5rem;
  margin-bottom: 1.2rem;
  padding-top: 1.2rem;
  border-top: 1px solid var(--border);
}
/* Inline form fieldsets inside core NF config */
#core-nf-form fieldset {
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 1rem 1.2rem;
  margin-bottom: 1rem;
  background: var(--surface);
  box-shadow: var(--shadow);
}

#core-nf-form legend {
  font-weight: 600;
  font-size: 0.8rem;
  color: var(--legend);
  letter-spacing: 0.04em;
  text-transform: uppercase;
  padding: 0 0.4rem;
}

#core-nf-form label {
  display: block;
  margin-bottom: 0.8rem;
}

#core-nf-form label strong {
  display: block;
  font-size: 0.8rem;
  color: var(--accent);
  margin-bottom: 0.1rem;
  letter-spacing: 0.02em;
}

#core-nf-form label div {
  font-size: 0.72rem;
  color: var(--text-muted);
  margin-bottom: 0.2rem;
}

#core-nf-form input[type="text"],
#core-nf-form input[type="number"] {
  width: 100%;
  padding: 0.4rem 0.6rem;
  background: var(--input-bg);
  border: 1px solid var(--input-border);
  border-radius: 5px;
  color: var(--text);
  font-size: 0.88rem;
  transition: border-color 0.15s, box-shadow 0.15s;
  outline: none;
}

#core-nf-form input[type="text"]:focus,
#core-nf-form input[type="number"]:focus {
  border-color: var(--accent);
  box-shadow: 0 0 0 2px color-mix(in srgb, var(--accent) 25%, transparent);
}

#core-nf-form input[type="checkbox"] {
  width: 1rem;
  height: 1rem;
  accent-color: var(--accent);
  cursor: pointer;
}

#core-nf-form .list-item {
  border: 1px dashed var(--border-dashed);
  border-radius: 6px;
  padding: 0.8rem 0.8rem 0.4rem;
  margin-bottom: 0.6rem;
  position: relative;
  background: var(--bg);
}

#core-nf-form .list-item-index {
  font-size: 0.68rem;
  color: var(--text-muted);
  margin-bottom: 0.4rem;
  font-style: italic;
}

#core-nf-form button.remove {
  position: absolute;
  top: 0.4rem;
  right: 0.4rem;
  background: transparent;
  border: 1px solid var(--border-dashed);
  border-radius: 4px;
  color: var(--text-muted);
  cursor: pointer;
  font-size: 0.72rem;
  padding: 0.1rem 0.35rem;
  transition: background 0.15s, color 0.15s;
}

#core-nf-form button.remove:hover {
  background: #c0392b22;
  color: #e05050;
  border-color: #e05050;
}

#core-nf-form button.add-item {
  background: var(--btn-bg);
  color: var(--btn-text);
  border: none;
  border-radius: 6px;
  padding: 0.4rem 0.9rem;
  font-size: 0.82rem;
  font-weight: 600;
  cursor: pointer;
  transition: opacity 0.15s, transform 0.1s;
  margin-top: 0.25rem;
}

#core-nf-form button.add-item:hover {
  opacity: 0.85;
  transform: translateY(-1px);
}

.skip-btn {
  background: transparent;
  border: 1px dashed var(--border-dashed);
  color: var(--text-muted);
  border-radius: 6px;
  padding: 0.4rem 0.9rem;
  font-size: 0.82rem;
  cursor: pointer;
  transition:
    border-color 0.15s,
    color 0.15s;
  display: inline-flex;
  align-items: center;
  gap: 0.3rem;
}

.skip-btn:hover {
  border-color: var(--text-muted);
  color: var(--text);
}

.undo-skip-btn {
  background: transparent;
  border: 1px solid var(--accent);
  color: var(--accent);
  border-radius: 6px;
  padding: 0.4rem 0.9rem;
  font-size: 0.82rem;
  cursor: pointer;
  transition:
    background 0.15s,
    color 0.15s;
  display: inline-flex;
  align-items: center;
  gap: 0.3rem;
}

.undo-skip-btn:hover {
  background: var(--btn-bg);
  color: var(--btn-text);
}

.next-btn {
  background: var(--btn-bg);
  border: none;
  color: var(--btn-text);
  border-radius: 6px;
  padding: 0.4rem 1.1rem;
  font-size: 0.85rem;
  font-weight: 600;
  cursor: pointer;
  transition:
    background 0.15s,
    transform 0.1s;
  display: inline-flex;
  align-items: center;
  gap: 0.3rem;
}

.next-btn:hover {
  background: var(--accent);
  transform: translateY(-1px);
}

.next-btn:active {
  transform: translateY(0);
}

/* Reset bar */
.reset-bar {
  display: flex;
  justify-content: flex-end;
  margin-top: 0.5rem;
}

.reset-btn {
  background: transparent;
  border: 1px dashed var(--border-dashed);
  color: var(--text-muted);
  border-radius: 6px;
  padding: 0.4rem 0.9rem;
  font-size: 0.82rem;
  cursor: pointer;
  transition:
    border-color 0.15s,
    color 0.15s;
}

.reset-btn:hover {
  border-color: #c0392b;
  color: #c0392b;
}

.reset-warning {
  display: none;
  background: var(--surface);
  border: 1px solid var(--border);
  border-left: 4px solid #c0392b;
  border-radius: 8px;
  padding: 1rem 1.2rem;
  margin-top: 1rem;
  color: var(--text-muted);
  font-size: 0.9rem;
}

.reset-warning.show {
  display: block;
}

.reset-warning strong {
  color: #c0392b;
}

.reset-warning-actions {
  display: flex;
  gap: 0.6rem;
  margin-top: 0.85rem;
  flex-wrap: wrap;
}

.reset-confirm-btn {
  background: #c0392b;
  border: none;
  color: #fff;
  border-radius: 6px;
  padding: 0.4rem 1rem;
  font-size: 0.82rem;
  font-weight: 600;
  cursor: pointer;
  transition: background 0.15s;
}

.reset-confirm-btn:hover {
  background: #a93226;
}

.reset-cancel-btn {
  background: transparent;
  border: 1px solid var(--border);
  color: var(--text-muted);
  border-radius: 6px;
  padding: 0.4rem 1rem;
  font-size: 0.82rem;
  cursor: pointer;
  transition:
    border-color 0.15s,
    color 0.15s;
}

.reset-cancel-btn:hover {
  border-color: var(--accent);
  color: var(--accent);
}

/* Build Core — Generate / Copy / Download bar */
.core-output-section {
  margin-top: 2rem;
  padding-top: 1.5rem;
  border-top: 1px solid var(--border);
}

.core-generate-bar {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  flex-wrap: wrap;
  margin-bottom: 1rem;
}

.core-generate-btn {
  background: var(--btn-bg);
  color: var(--btn-text);
  border: none;
  border-radius: 6px;
  padding: 0.5rem 1.2rem;
  font-size: 0.9rem;
  font-weight: 600;
  cursor: pointer;
  transition: opacity 0.15s, transform 0.1s;
  letter-spacing: 0.02em;
}

.core-generate-btn:hover {
  opacity: 0.85;
  transform: translateY(-1px);
}

.core-generate-btn:active {
  transform: translateY(0);
}

.core-copy-btn,
.core-download-btn {
  background: transparent;
  border: 1px solid var(--border);
  color: var(--text-muted);
  border-radius: 6px;
  padding: 0.5rem 1rem;
  font-size: 0.88rem;
  cursor: pointer;
  transition: border-color 0.15s, color 0.15s;
}

.core-copy-btn:hover,
.core-download-btn:hover {
  border-color: var(--accent);
  color: var(--accent);
}

/* Output section (shared) */
.output-section {
  margin-top: 0.5rem;
}

.output-section h2 {
  font-size: 0.85rem;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.06em;
  margin-bottom: 0.5rem;
  margin-top: 0;
}

textarea#core-output {
  width: 100%;
  height: 280px;
  background: var(--input-bg);
  border: 1px solid var(--input-border);
  border-radius: 6px;
  color: var(--text);
  font-family: 'JetBrains Mono', 'Fira Code', 'Cascadia Code', monospace;
  font-size: 0.82rem;
  padding: 0.75rem;
  resize: vertical;
  outline: none;
  transition: border-color 0.15s;
}

textarea#core-output:focus {
  border-color: var(--accent);
}

.copy-msg {
  font-size: 0.78rem;
  color: var(--accent);
  margin-left: 0.3rem;
  opacity: 0;
  transition: opacity 0.3s;
}

.copy-msg.show {
  opacity: 1;
}