* { margin: 0; padding: 0; box-sizing: border-box; }
:root {
  --bg: #f5f7fa; --card: #fff; --border: #e2e8f0; --text: #1a202c;
  --text2: #64748b; --primary: #4f46e5; --primary-light: #eef2ff;
  --hover: #f1f5f9; --radius: 8px; --shadow: 0 1px 3px rgba(0,0,0,.08);
  --font: 'Segoe UI', system-ui, -apple-system, sans-serif;
  --mono: 'Cascadia Code', 'Fira Code', Consolas, monospace;
  --diff-add-bg: #dcfce7; --diff-add-text: #166534;
  --diff-del-bg: #fee2e2; --diff-del-text: #991b1b;
  --regex-match-bg: #fef08a;
  --toast-bg: #1a202c; --toast-text: #fff;
  --code-bg: #1a2332; --code-text: #e6edf3; --inline-code-bg: #eef2ff;
  color-scheme: light dark;
}
@media (prefers-color-scheme: dark) {
  :root {
    --bg: #0f172a; --card: #1e293b; --border: #334155; --text: #e2e8f0;
    --text2: #94a3b8; --primary: #818cf8; --primary-light: #1e1b4b;
    --hover: #1e293b; --shadow: 0 1px 3px rgba(0,0,0,.3);
    --diff-add-bg: #14532d; --diff-add-text: #bbf7d0;
    --diff-del-bg: #7f1d1d; --diff-del-text: #fecaca;
    --regex-match-bg: #713f12;
    --toast-bg: #e2e8f0; --toast-text: #1a202c;
    --code-bg: #090d14; --code-text: #e6edf3; --inline-code-bg: #2d3a4f;
  }
}
html { font-size: 14px; }
body {
  font-family: var(--font);
  background: var(--bg);
  color: var(--text);
  display: flex;
  flex-direction: column;
  height: 100vh;
  overflow: hidden;
}

/* Footer */
.footer {
  padding: 16px 32px;
  border-top: 1px solid var(--border);
  background: var(--card);
  font-size: 0.8rem;
  color: var(--text2);
  flex-shrink: 0;
  display: flex;
  justify-content: center;
  align-items: center;
  flex-wrap: wrap;
  gap: 8px 16px;
  position: relative;
}

.footer a {
  color: var(--text2);
  text-decoration: none;
  margin: 0 8px;
}

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

.footer img {
  vertical-align: middle;
  margin-right: 4px;
  width: 16px;
  height: 16px;
}

.footer-right {
  position: absolute;
  right: 32px;
}

/* Main with footer */
.main-container {
  display: flex;
  flex: 1;
  overflow: hidden;
}

/* Sidebar */
.sidebar {
  width: 240px; min-width: 240px; background: var(--card); border-right: 1px solid var(--border);
  display: flex; flex-direction: column; overflow: hidden;
}
.sidebar-header {
  padding: 20px; border-bottom: 1px solid var(--border); flex-shrink: 0;
}
.sidebar-header h1 { font-size: 1.3rem; color: var(--primary); letter-spacing: -0.5px; }
.sidebar-header p { font-size: .75rem; color: var(--text2); margin-top: 2px; }
.sidebar-search {
  padding: 12px; flex-shrink: 0;
}
.sidebar-search input {
  width: 100%; padding: 8px 12px; border: 1px solid var(--border); border-radius: var(--radius);
  font-size: .85rem; outline: none; background: var(--bg);
}
.sidebar-search input:focus { border-color: var(--primary); }
.sidebar-nav {
  flex: 1; overflow-y: auto; padding: 4px 8px 20px;
}
.sidebar-nav::-webkit-scrollbar { width: 4px; }
.sidebar-nav::-webkit-scrollbar-thumb { background: var(--border); border-radius: 4px; }
.nav-group { margin-bottom: 4px; }
.nav-group-title {
  font-size: .7rem; font-weight: 600; color: var(--text2); text-transform: uppercase;
  letter-spacing: .5px; padding: 10px 10px 4px; user-select: none;
}
.nav-item {
  display: flex; align-items: center; gap: 8px; padding: 7px 10px; border-radius: 6px;
  cursor: pointer; font-size: .85rem; color: var(--text); transition: all .15s;
  user-select: none; white-space: nowrap;
}
.nav-item:hover { background: var(--hover); }
.nav-item.active { background: var(--primary-light); color: var(--primary); font-weight: 500; }
.nav-item .icon { width: 18px; text-align: center; font-size: .9rem; flex-shrink: 0; }

/* Main */
.main { flex: 1; overflow-y: auto; padding: 28px 36px; }
.main::-webkit-scrollbar { width: 6px; }
.main::-webkit-scrollbar-thumb { background: var(--border); border-radius: 4px; }

.tool-panel { display: none; }
.tool-panel.active { display: block; }
.tool-title { font-size: 1.4rem; font-weight: 600; margin-bottom: 6px; }
.tool-desc { color: var(--text2); font-size: .85rem; margin-bottom: 20px; }

/* Common Components */
.card {
  background: var(--card); border: 1px solid var(--border); border-radius: var(--radius);
  padding: 18px; margin-bottom: 16px; box-shadow: var(--shadow);
}
.row { display: flex; gap: 16px; }
.row > .col { flex: 1; min-width: 0; }
label { display: block; font-size: .8rem; font-weight: 500; margin-bottom: 6px; color: var(--text2); }
textarea, input[type="text"], input[type="number"], select {
  width: 100%; padding: 10px 12px; border: 1px solid var(--border); border-radius: var(--radius);
  font-family: var(--mono); font-size: .85rem; background: var(--bg); color: var(--text);
  outline: none; resize: vertical; transition: border .15s;
}
textarea:focus, input[type="text"]:focus, input[type="number"]:focus, select:focus {
  border-color: var(--primary);
}
textarea { min-height: 120px; line-height: 1.6; }
.textarea-sm { min-height: 80px; }
.textarea-lg { min-height: 200px; }
select { cursor: pointer; appearance: auto; }
.btn {
  display: inline-flex; align-items: center; gap: 6px; padding: 8px 16px;
  border: 1px solid var(--border); border-radius: var(--radius); background: var(--card);
  font-size: .8rem; font-weight: 500; cursor: pointer; color: var(--text);
  transition: all .15s; user-select: none;
}
.btn:hover { background: var(--hover); }
.btn-primary { background: var(--primary); color: #fff; border-color: var(--primary); }
.btn-primary:hover { background: var(--primary); color: #fff; border-color: var(--primary); opacity: .9; }
.btn-group { display: flex; gap: 8px; flex-wrap: wrap; margin-bottom: 12px; }
.output-area {
  background: var(--bg); border: 1px solid var(--border); border-radius: var(--radius);
  padding: 12px; font-family: var(--mono); font-size: .85rem; min-height: 60px;
  word-break: break-all; white-space: pre-wrap; line-height: 1.6; max-height: 400px; overflow: auto;
}
.output-area::-webkit-scrollbar { width: 4px; }
.output-area::-webkit-scrollbar-thumb { background: var(--border); border-radius: 4px; }
.tag {
  display: inline-block; padding: 2px 8px; border-radius: 4px; font-size: .75rem;
  background: var(--primary-light); color: var(--primary); font-weight: 500;
}
table { width: 100%; border-collapse: collapse; font-size: .85rem; }
table th, table td { padding: 8px 12px; border-bottom: 1px solid var(--border); text-align: left; }
table th { font-weight: 600; font-size: .8rem; color: var(--text2); background: var(--bg); position: sticky; top: 0; }
table tr:hover td { background: var(--hover); }
.table-wrap { max-height: 400px; overflow: auto; border: 1px solid var(--border); border-radius: var(--radius); }
.table-wrap::-webkit-scrollbar { width: 4px; }
.table-wrap::-webkit-scrollbar-thumb { background: var(--border); border-radius: 4px; }
.inline-group { display: flex; gap: 8px; align-items: center; flex-wrap: wrap; }
.color-preview {
  width: 48px; height: 48px; border-radius: var(--radius); border: 1px solid var(--border);
  flex-shrink: 0;
}
.result-box {
  display: inline-block; padding: 6px 14px; background: var(--primary-light);
  border-radius: var(--radius); font-family: var(--mono); font-size: .9rem;
  color: var(--primary); font-weight: 500;
}
.diff-add { background: var(--diff-add-bg); color: var(--diff-add-text); }
.diff-del { background: var(--diff-del-bg); color: var(--diff-del-text); }
.diff-line { font-family: var(--mono); font-size: .82rem; padding: 1px 8px; white-space: pre-wrap; }
.cron-part { text-align: center; }
.cron-part input { text-align: center; }
.cron-part small { display: block; color: var(--text2); margin-top: 2px; font-size: .7rem; }
.regex-match { background: var(--regex-match-bg); border-radius: 2px; padding: 0 1px; }
.copy-toast {
  position: fixed; bottom: 30px; left: 50%; transform: translateX(-50%);
  background: var(--toast-bg); color: var(--toast-text); padding: 8px 20px; border-radius: 20px;
  font-size: .8rem; opacity: 0; transition: opacity .3s; pointer-events: none; z-index: 999;
}
.copy-toast.show { opacity: 1; }

/* MD Preview */
.md-code { background: var(--code-bg); color: var(--code-text); padding: 14px 16px; border-radius: 6px; overflow-x: auto; font-size: .85em; border: 1px solid var(--border); display: block; }
.md-code code { font-family: var(--mono); color: var(--code-text); background: transparent; font-size: inherit; }
.md-inline-code { background: var(--inline-code-bg); color: var(--primary); padding: 2px 6px; border-radius: 3px; font-size: .85em; font-family: var(--mono); font-weight: 500; }
.md-blockquote { border-left: 3px solid var(--primary); padding: 4px 12px; margin: 8px 0; color: var(--text2); }
.md-table { width: 100%; border-collapse: collapse; margin: 8px 0; }
.md-table th, .md-table td { border: 1px solid var(--border); padding: 6px 12px; text-align: left; }
.md-table th { background: var(--hover); font-weight: 600; }
.md-hr { border: none; border-top: 1px solid var(--border); margin: 12px 0; }
.md-heading { margin: 8px 0; }
.md-p { margin: 4px 0; }
.md-ul, .md-ol { margin: 4px 0; padding-left: 24px; }
.md-check { display: inline-block; width: 16px; height: 16px; border: 2px solid var(--text2); border-radius: 3px; margin-right: 6px; vertical-align: middle; text-align: center; line-height: 16px; font-size: 11px; }
.md-check.checked { background: var(--primary); border-color: var(--primary); color: #fff; }

@media (max-width: 768px) {
  .sidebar { width: 200px; min-width: 200px; }
  .main { padding: 20px; }
  .row { flex-direction: column; }
}