:root {
  --bg: #f7f8fa;
  --card: #ffffff;
  --text: #2b2f36;
  --muted: #6b7280;
  --border: #e4e7eb;
  --primary: #4f6ef7;
  --primary-hover: #3f5be0;
  --success: #16a34a;
  --error: #dc2626;
  --code-bg: #fbfbfc;
  --radius: 10px;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC",
    "Microsoft YaHei", sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
}

/* Header */
.site-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 14px 32px;
  background: var(--card);
  border-bottom: 1px solid var(--border);
}
.brand {
  display: flex;
  align-items: center;
  gap: 10px;
  text-decoration: none;
  color: var(--text);
  font-weight: 700;
  font-size: 17px;
}
.brand-mark {
  width: 30px;
  height: 30px;
  border-radius: 8px;
  background: linear-gradient(135deg, #6a8bff, #4f6ef7);
  color: #fff;
  display: grid;
  place-items: center;
  font-weight: 700;
}
.brand-text small {
  color: var(--muted);
  font-weight: 400;
  font-size: 12px;
}
.site-nav a {
  margin-left: 20px;
  text-decoration: none;
  color: var(--muted);
  font-size: 14px;
}
.site-nav a:hover { color: var(--primary); }

/* Hero */
.hero {
  text-align: center;
  padding: 40px 20px 20px;
}
.hero h1 { font-size: 28px; margin: 0 0 8px; }
.subtitle { color: var(--muted); margin: 0; font-size: 14px; }

/* Tool */
.tool {
  max-width: 1100px;
  margin: 20px auto;
  padding: 0 20px;
}
.toolbar {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-bottom: 14px;
}
.btn {
  padding: 8px 16px;
  border: 1px solid var(--border);
  background: var(--card);
  color: var(--text);
  border-radius: var(--radius);
  cursor: pointer;
  font-size: 14px;
  transition: all 0.15s;
}
.btn:hover { border-color: var(--primary); color: var(--primary); }
.btn.primary { background: var(--primary); color: #fff; border-color: var(--primary); }
.btn.primary:hover { background: var(--primary-hover); color: #fff; }
.btn.ghost { color: var(--muted); }

.editor {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 14px;
}
@media (max-width: 760px) {
  .editor { grid-template-columns: 1fr; }
}
.pane { display: flex; flex-direction: column; }
.pane label {
  font-size: 13px;
  font-weight: 600;
  margin-bottom: 6px;
  color: var(--muted);
}
#input, .output {
  width: 100%;
  min-height: 380px;
  padding: 14px;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  background: var(--code-bg);
  font-family: "SF Mono", "Cascadia Code", "Consolas", monospace;
  font-size: 13px;
  line-height: 1.6;
  resize: vertical;
  white-space: pre-wrap;
  word-break: break-all;
  overflow: auto;
}
#input:focus { outline: none; border-color: var(--primary); }
.output { margin: 0; }

.status {
  margin-top: 14px;
  padding: 10px 14px;
  border-radius: var(--radius);
  font-size: 14px;
  min-height: 20px;
}
.status.success { background: #ecfdf5; color: var(--success); }
.status.error { background: #fef2f2; color: var(--error); }

/* Intro */
.intro {
  max-width: 1100px;
  margin: 30px auto;
  padding: 24px;
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
}
.intro h2 { font-size: 18px; margin-top: 0; }
.intro ul { padding-left: 20px; }
.intro code {
  background: var(--bg);
  padding: 2px 6px;
  border-radius: 4px;
  font-size: 13px;
}
.note { color: var(--muted); font-size: 13px; margin-bottom: 0; }

/* Footer */
.site-footer {
  text-align: center;
  padding: 24px;
  color: var(--muted);
  font-size: 13px;
  border-top: 1px solid var(--border);
  margin-top: 40px;
}