:root {
  --vu-red: #e60023;
  --vu-red-hover: #c9001f;
  --vu-red-soft: rgba(230, 0, 35, 0.08);
  --vu-text: #17181c;
  --vu-text-secondary: #596171;
  --vu-text-muted: #8b93a1;
  --vu-bg: #ffffff;
  --vu-bg-subtle: #f7f8fa;
  --vu-border: #e4e7ec;
  --vu-ease: cubic-bezier(0.22, 1, 0.36, 1);
}

* { box-sizing: border-box; }

html, body {
  margin: 0;
  padding: 0;
  background: var(--vu-bg);
  color: var(--vu-text);
  font-family: "Segoe UI", "PingFang SC", "Noto Sans SC", "Microsoft YaHei", sans-serif;
  line-height: 1.55;
  -webkit-font-smoothing: antialiased;
}

a { color: var(--vu-red); text-decoration: none; }
a:hover { color: var(--vu-red-hover); }

.vu-header {
  border-bottom: 1px solid var(--vu-border);
  background: var(--vu-bg);
}

.vu-header-inner {
  width: min(100% - 2rem, 960px);
  margin: 0 auto;
  min-height: 64px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
}

.vu-brand {
  display: flex;
  align-items: baseline;
  gap: 0.75rem;
  color: var(--vu-text);
  font-weight: 600;
  letter-spacing: -0.02em;
}

.vu-brand-mark {
  color: var(--vu-red);
}

.vu-brand-sub {
  font-size: 0.95rem;
  font-weight: 500;
  color: var(--vu-text-secondary);
}

.vu-nav {
  display: flex;
  flex-wrap: wrap;
  gap: 0.25rem 1rem;
  font-size: 0.9rem;
}

.vu-nav a {
  color: var(--vu-text-secondary);
}

.vu-nav a:hover { color: var(--vu-red); }

.vu-main {
  width: min(100% - 2rem, 960px);
  margin: 0 auto;
  padding: 2.5rem 0 4rem;
}

.vu-eyebrow {
  margin: 0;
  font-size: 0.875rem;
  font-weight: 500;
  letter-spacing: 0.04em;
  color: var(--vu-red);
}

.vu-title {
  margin: 0.75rem 0 0;
  font-size: clamp(1.75rem, 4vw, 2.4rem);
  font-weight: 600;
  letter-spacing: -0.03em;
  line-height: 1.15;
}

.vu-lead {
  margin: 1rem 0 0;
  max-width: 36rem;
  color: var(--vu-text-secondary);
  font-size: 1.05rem;
  line-height: 1.7;
}

.vu-status {
  margin-top: 1.5rem;
  padding: 1rem 1.1rem;
  border: 1px solid var(--vu-border);
  border-radius: 8px;
  background: var(--vu-bg-subtle);
}

.vu-status h2 {
  margin: 0;
  font-size: 1.05rem;
  font-weight: 600;
}

.vu-status p {
  margin: 0.5rem 0 0;
  color: var(--vu-text-secondary);
  font-size: 0.95rem;
}

.vu-status a.button {
  display: inline-flex;
  margin-top: 0.85rem;
  min-height: 44px;
  align-items: center;
  padding: 0.65rem 1rem;
  border-radius: 6px;
  background: var(--vu-red);
  color: #fff;
  font-weight: 500;
}

.vu-status a.button:hover {
  background: var(--vu-red-hover);
  color: #fff;
}

.vu-status a.link-muted {
  display: inline-block;
  margin-top: 0.75rem;
  color: var(--vu-text-muted);
  font-size: 0.9rem;
}

.vu-grid {
  display: grid;
  gap: 1.25rem;
  margin-top: 2.25rem;
}

@media (min-width: 768px) {
  .vu-grid { grid-template-columns: 1fr 1fr; }
}

.vu-panel {
  border: 1px solid var(--vu-border);
  border-radius: 10px;
  background: var(--vu-bg);
  padding: 1.35rem 1.4rem 1.5rem;
}

.vu-panel h2 {
  margin: 0;
  font-size: 1.15rem;
  font-weight: 600;
  letter-spacing: -0.02em;
}

.vu-panel p {
  margin: 0.65rem 0 0;
  color: var(--vu-text-secondary);
  font-size: 0.95rem;
  line-height: 1.65;
}

.vu-steps {
  margin: 1.1rem 0 0;
  padding: 0;
  list-style: none;
  display: grid;
  gap: 0.85rem;
}

.vu-steps li {
  display: grid;
  grid-template-columns: 2rem 1fr;
  gap: 0.75rem;
  align-items: start;
}

.vu-step-num {
  width: 2rem;
  height: 2rem;
  border-radius: 999px;
  background: var(--vu-red-soft);
  color: var(--vu-red);
  display: inline-flex;
  align-items: center;
  justify-content: center;
  font-size: 0.8rem;
  font-weight: 600;
}

.vu-step-body strong {
  display: block;
  font-weight: 600;
}

.vu-code {
  display: inline-block;
  margin-top: 0.25rem;
  padding: 0.15rem 0.45rem;
  border-radius: 4px;
  background: var(--vu-bg-subtle);
  border: 1px solid var(--vu-border);
  font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  font-size: 0.88rem;
  color: var(--vu-text);
  word-break: break-all;
}

.vu-drop {
  margin-top: 1.1rem;
  border: 1.5px dashed var(--vu-border);
  border-radius: 10px;
  background: var(--vu-bg-subtle);
  min-height: 160px;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 0.65rem;
  padding: 1.25rem;
  text-align: center;
  transition: border-color 160ms var(--vu-ease), background 160ms var(--vu-ease);
}

.vu-drop.is-drag {
  border-color: var(--vu-red);
  background: var(--vu-red-soft);
}

.vu-drop p {
  margin: 0;
  color: var(--vu-text-secondary);
  font-size: 0.95rem;
}

.vu-file-name {
  color: var(--vu-text);
  font-size: 0.9rem;
  word-break: break-word;
}

.vu-btn {
  appearance: none;
  border: 0;
  border-radius: 6px;
  min-height: 44px;
  padding: 0.7rem 1.15rem;
  background: var(--vu-red);
  color: #fff;
  font-size: 0.95rem;
  font-weight: 500;
  cursor: pointer;
}

.vu-btn:hover { background: var(--vu-red-hover); }
.vu-btn:disabled {
  opacity: 0.55;
  cursor: not-allowed;
}

.vu-btn-secondary {
  background: #fff;
  color: var(--vu-text);
  border: 1px solid var(--vu-border);
}

.vu-btn-secondary:hover {
  background: var(--vu-bg-subtle);
  color: var(--vu-text);
}

.vu-hidden-input { display: none; }

.vu-feedback {
  margin-top: 0.9rem;
  font-size: 0.9rem;
  color: var(--vu-text-secondary);
}

.vu-feedback.error { color: #b42318; }
.vu-feedback.ok { color: #067647; }

.vu-footer {
  width: min(100% - 2rem, 960px);
  margin: 0 auto;
  padding: 0 0 2.5rem;
  color: var(--vu-text-muted);
  font-size: 0.8rem;
}

.vu-prompt {
  margin-top: 1rem;
  padding: 0.9rem 1rem;
  border-radius: 8px;
  border: 1px solid var(--vu-border);
  background: #fff;
}

.vu-prompt code {
  display: block;
  margin-top: 0.45rem;
  word-break: break-all;
  font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  font-size: 0.88rem;
}