:root {
  --bg: #f7f8fa;
  --panel: #ffffff;
  --border: #e3e6ea;
  --text: #1f2937;
  --muted: #6b7280;
  --accent: #2563eb;
  --accent-soft: #eff4ff;
  --danger: #dc2626;
  --success: #16a34a;
  --radius: 10px;
  --shadow: 0 1px 3px rgba(0,0,0,.06);
}
html[data-theme="dark"] {
  --bg: #0f1720;
  --panel: #17212b;
  --border: #283541;
  --text: #e5e7eb;
  --muted: #9ca3af;
  --accent: #60a5fa;
  --accent-soft: #1a2a44;
  --danger: #f87171;
  --success: #4ade80;
  --shadow: 0 1px 3px rgba(0,0,0,.35);
}

* { box-sizing: border-box; }
html, body { margin: 0; padding: 0; }
body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

/* Top bar */
.topbar {
  position: sticky; top: 0; z-index: 10;
  display: flex; align-items: center; justify-content: space-between;
  padding: 12px 24px;
  background: var(--panel);
  border-bottom: 1px solid var(--border);
}
.brand { font-size: 20px; font-weight: 700; color: var(--text); text-decoration: none; }
.brand span { color: var(--accent); }
.topbar-actions { display: flex; align-items: center; gap: 14px; }
.privacy-note { font-size: 13px; color: var(--success); }
#theme {
  border: 1px solid var(--border); background: var(--panel); color: var(--text);
  width: 34px; height: 34px; border-radius: 8px; cursor: pointer; font-size: 16px;
}

/* Layout */
.layout { display: flex; flex: 1; width: 100%; max-width: 1200px; margin: 0 auto; padding: 24px; gap: 24px; }
.sidebar { width: 240px; flex-shrink: 0; }
.search-label { display: block; font-size: 13px; color: var(--muted); margin-bottom: 6px; }
#search {
  width: 100%; padding: 9px 12px; border: 1px solid var(--border); border-radius: 8px;
  background: var(--panel); color: var(--text); font-size: 14px; margin-bottom: 14px; outline: none;
}
#search:focus { border-color: var(--accent); }
.tool-nav { display: flex; flex-direction: column; gap: 2px; }
.tool-nav a {
  display: block; padding: 8px 12px; border-radius: 8px; text-decoration: none;
  color: var(--muted); font-size: 14px; cursor: pointer;
}
.tool-nav a:hover { background: var(--accent-soft); color: var(--text); }
.tool-nav a.active { background: var(--accent-soft); color: var(--accent); font-weight: 600; }
.tool-nav .nav-group { margin-top: 10px; padding: 0 12px; font-size: 12px; color: var(--muted); text-transform: uppercase; letter-spacing: .05em; }
.tool-nav .nav-group:first-child { margin-top: 0; }

/* Panels */
.panels { flex: 1; min-width: 0; }
.panel { display: none; background: var(--panel); border: 1px solid var(--border); border-radius: var(--radius); box-shadow: var(--shadow); padding: 24px; }
.panel.active { display: block; }
.panel h2 { margin: 0 0 6px; font-size: 22px; }
.panel .desc { margin: 0 0 20px; color: var(--muted); font-size: 14px; }

/* Form */
.row { display: flex; gap: 12px; flex-wrap: wrap; margin-bottom: 12px; }
.field { flex: 1; min-width: 200px; }
label { display: block; font-size: 13px; color: var(--muted); margin-bottom: 5px; }
textarea, input[type="text"], input[type="number"], select {
  width: 100%; padding: 9px 12px; border: 1px solid var(--border); border-radius: 8px;
  background: var(--bg); color: var(--text); font-size: 14px; font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace; outline: none;
}
textarea { min-height: 120px; resize: vertical; }
textarea.output { background: var(--accent-soft); }
input:focus, textarea:focus, select:focus { border-color: var(--accent); }

button {
  padding: 8px 16px; border: 1px solid var(--border); border-radius: 8px;
  background: var(--panel); color: var(--text); font-size: 14px; cursor: pointer;
}
button:hover { border-color: var(--accent); color: var(--accent); }
button.primary { background: var(--accent); border-color: var(--accent); color: #fff; }
button.primary:hover { opacity: .9; color: #fff; }
.btn-group { display: flex; gap: 10px; flex-wrap: wrap; margin-bottom: 12px; }

.check-row { display: flex; align-items: center; gap: 14px; font-size: 14px; }
.check-row label { margin: 0; color: var(--text); display: flex; align-items: center; gap: 6px; }
.check-row input[type="checkbox"], .check-row input[type="radio"] { accent-color: var(--accent); }

.result-block { margin-top: 14px; }
.result-title { font-size: 13px; color: var(--muted); margin-bottom: 5px; }
.hash-lines { display: flex; flex-direction: column; gap: 8px; }
.hash-row { display: flex; align-items: center; gap: 8px; }
.hash-row .algo { width: 90px; font-size: 13px; color: var(--muted); flex-shrink: 0; }
.hash-row .val { flex: 1; font-family: ui-monospace, Menlo, Consolas, monospace; font-size: 13px; word-break: break-all; background: var(--bg); border: 1px solid var(--border); border-radius: 6px; padding: 6px 10px; }

.muted { color: var(--muted); font-size: 13px; }
.error-msg { color: var(--danger); font-size: 13px; margin-top: 8px; }
.copy-hint { color: var(--success); font-size: 13px; margin-top: 8px; }

.footer { text-align: center; color: var(--muted); font-size: 12px; padding: 18px; border-top: 1px solid var(--border); }

@media (max-width: 820px) {
  .layout { flex-direction: column; padding: 14px; }
  .sidebar { width: 100%; }
  .privacy-note { display: none; }
}