/* === Reset & Variables === */
:root {
  --primary: #2563eb;
  --primary-hover: #1d4ed8;
  --primary-light: #eff6ff;
  --primary-gradient: linear-gradient(135deg, #2563eb 0%, #7c3aed 100%);
  --bg: #f1f5f9;
  --card-bg: #ffffff;
  --text: #0f172a;
  --text-secondary: #64748b;
  --border: #e2e8f0;
  --shadow-sm: 0 1px 2px rgba(0,0,0,0.05);
  --shadow: 0 1px 3px rgba(0,0,0,0.08), 0 1px 2px rgba(0,0,0,0.04);
  --shadow-md: 0 4px 12px rgba(0,0,0,0.08);
  --shadow-hover: 0 8px 24px rgba(0,0,0,0.12);
  --radius: 12px;
  --radius-sm: 8px;
  --max-width: 1200px;
  --transition: 0.2s cubic-bezier(0.4, 0, 0.2, 1);
}

*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

html { scroll-behavior: smooth; font-size: 16px; -webkit-text-size-adjust: 100%; }

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, "Noto Sans SC", "PingFang SC", "Microsoft YaHei", sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

a { color: var(--primary); text-decoration: none; -webkit-tap-highlight-color: transparent; }
a:hover { color: var(--primary-hover); }

img, canvas { max-width: 100%; display: block; }

::selection { background: #bfdbfe; color: var(--text); }

.container { width: 100%; max-width: var(--max-width); margin: 0 auto; padding: 0 20px; }

/* === Header === */
.site-header {
  background: rgba(255,255,255,0.85);
  -webkit-backdrop-filter: blur(12px);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
  position: sticky;
  top: 0;
  z-index: 100;
}
.site-header .container { display: flex; align-items: center; justify-content: space-between; height: 60px; }
.logo {
  display: flex; align-items: center; gap: 10px; font-size: 20px; font-weight: 700;
  color: var(--text); -webkit-user-select: none; user-select: none;
}
.logo:hover { color: var(--primary); }
.logo-icon { width: 34px; height: 34px; }
.logo em { font-style: normal; font-weight: 400; color: var(--text-secondary); }

.main-nav { display: flex; flex-direction: column; gap: 2px; }
.nav-row { display: flex; gap: 2px; }
.nav-row a {
  padding: 5px 12px; font-size: 13px; color: var(--text-secondary);
  border-radius: 20px; white-space: nowrap; transition: var(--transition); font-weight: 500;
}
.nav-row a:hover { color: var(--primary); background: var(--primary-light); }

.nav-toggle {
  display: none; background: none; border: none; cursor: pointer;
  color: var(--text); padding: 8px; border-radius: var(--radius-sm); transition: var(--transition);
}
.nav-toggle:hover { background: var(--border); }

/* === Hero === */
.hero { text-align: center; padding: 64px 0 40px; position: relative; }
.hero::before {
  content: ''; position: absolute; top: -120px; left: 50%; transform: translateX(-50%);
  width: 600px; height: 600px; background: radial-gradient(circle, rgba(37,99,235,0.08) 0%, transparent 70%);
  border-radius: 50%; pointer-events: none;
}
.hero h1 {
  font-size: 40px; font-weight: 800; background: var(--primary-gradient);
  -webkit-background-clip: text; -webkit-text-fill-color: transparent; background-clip: text;
  margin-bottom: 10px; letter-spacing: -0.5px;
}
.hero p { color: var(--text-secondary); font-size: 16px; margin-bottom: 24px; }

.search-box { max-width: 520px; margin: 0 auto 14px; position: relative; }
.search-box::before {
  content: '🔍'; position: absolute; left: 18px; top: 50%; transform: translateY(-50%);
  font-size: 16px; pointer-events: none; z-index: 1;
}
.search-box input {
  width: 100%; padding: 14px 20px 14px 48px; font-size: 15px;
  border: 2px solid var(--border); border-radius: 50px; outline: none;
  transition: var(--transition); background: var(--card-bg); box-shadow: var(--shadow-sm);
}
.search-box input:focus { border-color: var(--primary); box-shadow: 0 0 0 4px rgba(37,99,235,0.1); }
.search-box input::-webkit-search-cancel-button { cursor: pointer; }
.search-box input::placeholder { color: #94a3b8; }

.stats-line { font-size: 13px; color: var(--text-secondary); }

/* === Category Section === */
.cat-section { padding: 20px 0 48px; }
.cat-head { display: flex; align-items: center; gap: 10px; margin-bottom: 18px; }
.cat-emoji { font-size: 26px; line-height: 1; }
.cat-head h2 { font-size: 22px; font-weight: 700; color: var(--text); }
.cat-head .count {
  font-size: 13px; color: var(--text-secondary); margin-left: auto;
  background: #f1f5f9; padding: 2px 10px; border-radius: 12px;
}

/* === Tool Grid === */
.tool-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(250px, 1fr)); gap: 14px; }
.tool-link {
  display: block; padding: 20px; background: var(--card-bg);
  border: 1px solid var(--border); border-radius: var(--radius);
  transition: var(--transition); color: var(--text); position: relative; overflow: hidden;
}
.tool-link::before {
  content: ''; position: absolute; top: 0; left: 0; width: 100%; height: 3px;
  background: var(--primary-gradient); transform: scaleX(0); transition: transform var(--transition);
  transform-origin: left;
}
.tool-link:hover { border-color: #93c5fd; box-shadow: var(--shadow-hover); transform: translateY(-3px); color: var(--text); }
.tool-link:hover::before { transform: scaleX(1); }
.tool-link b {
  display: flex; align-items: center; gap: 8px; font-size: 15px; font-weight: 600; margin-bottom: 6px; color: var(--text);
}
.tool-link b::before {
  content: ''; display: inline-block; width: 8px; height: 8px; border-radius: 50%;
  background: var(--primary-gradient); flex-shrink: 0;
}
.tool-link small { font-size: 12px; color: var(--text-secondary); line-height: 1.5; }

/* === Footer === */
.site-footer {
  margin-top: auto; background: var(--card-bg); border-top: 1px solid var(--border);
  text-align: center; padding: 24px 0; font-size: 13px; color: var(--text-secondary);
}

/* === Back to top === */
.back-to-top {
  position: fixed; bottom: 28px; right: 28px; width: 44px; height: 44px;
  background: var(--card-bg); border: 1px solid var(--border); border-radius: 50%;
  display: flex; align-items: center; justify-content: center; cursor: pointer;
  opacity: 0; visibility: hidden; transition: var(--transition);
  box-shadow: var(--shadow-md); z-index: 99; font-size: 18px; color: var(--text-secondary);
}
.back-to-top.visible { opacity: 1; visibility: visible; }
.back-to-top:hover { background: var(--primary-light); color: var(--primary); border-color: var(--primary); }

/* === Tool Page Layout === */
.tool-page { padding: 32px 0; flex: 1; }
.tool-page .container { max-width: 900px; }

.tool-header { margin-bottom: 24px; }
.tool-header .back-link {
  display: inline-flex; align-items: center; gap: 6px; font-size: 13px;
  color: var(--text-secondary); margin-bottom: 14px; padding: 4px 12px;
  border-radius: 20px; transition: var(--transition); background: var(--card-bg); border: 1px solid var(--border);
}
.tool-header .back-link:hover { color: var(--primary); background: var(--primary-light); border-color: #93c5fd; }
.tool-header h1 { font-size: 28px; font-weight: 700; }
.tool-header .desc { color: var(--text-secondary); font-size: 14px; margin-top: 6px; }

.tool-body { background: var(--card-bg); border: 1px solid var(--border); border-radius: var(--radius); overflow: hidden; box-shadow: var(--shadow-sm); }
.tool-body .input-area { padding: 20px; }

.tool-body .input-area textarea,
.tool-body .input-area input[type="text"],
.tool-body .input-area input[type="search"] {
  width: 100%; min-height: 160px; padding: 14px;
  font-family: "SF Mono","Fira Code","Consolas","Liberation Mono","JetBrains Mono",monospace;
  font-size: 14px; border: 1px solid var(--border); border-radius: var(--radius-sm);
  resize: vertical; outline: none; transition: var(--transition); background: #fafbfc; color: var(--text); line-height: 1.6;
}
.tool-body .input-area input[type="text"],
.tool-body .input-area input[type="search"] { min-height: auto; }
.tool-body .input-area textarea:focus,
.tool-body .input-area input[type="text"]:focus,
.tool-body .input-area input[type="search"]:focus {
  border-color: var(--primary); box-shadow: 0 0 0 3px rgba(37,99,235,0.08); background: #fff;
}

.tool-body .actions { display: flex; flex-wrap: wrap; gap: 8px; padding: 0 20px 20px; }

.btn {
  display: inline-flex; align-items: center; gap: 6px; padding: 9px 20px; font-size: 14px;
  font-weight: 500; border: 1px solid var(--border); border-radius: var(--radius-sm);
  cursor: pointer; background: var(--card-bg); color: var(--text);
  transition: var(--transition); white-space: nowrap; -webkit-user-select: none; user-select: none;
}
.btn:hover { background: var(--primary-light); border-color: #93c5fd; color: var(--primary); }
.btn:active { transform: scale(0.97); }
.btn-primary { background: var(--primary-gradient); color: #fff; border-color: transparent; }
.btn-primary:hover { opacity: 0.9; color: #fff; box-shadow: 0 4px 12px rgba(37,99,235,0.3); }
.btn:disabled { opacity: 0.5; cursor: not-allowed; pointer-events: none; }

.msg { padding: 12px 20px; font-size: 13px; border-radius: var(--radius-sm); margin: 0 20px 12px; animation: msgSlideIn 0.25s ease-out; }
@keyframes msgSlideIn { from { opacity: 0; transform: translateY(-6px); } to { opacity: 1; transform: translateY(0); } }
.msg-error { background: #fef2f2; color: #dc2626; border: 1px solid #fecaca; }
.msg-success { background: #f0fdf4; color: #16a34a; border: 1px solid #bbf7d0; }
.msg-info { background: var(--primary-light); color: var(--primary); border: 1px solid #bfdbfe; }

.output-area { padding: 0 20px 20px; }
.output-area textarea, .output-area pre {
  width: 100%; min-height: 120px; padding: 14px;
  font-family: "SF Mono","Fira Code","Consolas","Liberation Mono","JetBrains Mono",monospace;
  font-size: 14px; border: 1px solid var(--border); border-radius: var(--radius-sm);
  background: #f8fafc; white-space: pre-wrap; word-break: break-all; line-height: 1.6; color: var(--text);
}
.output-area pre { overflow-x: auto; }

.options {
  display: flex; flex-wrap: wrap; gap: 14px; padding: 0 20px 12px; align-items: center;
}
.options label {
  font-size: 13px; color: var(--text-secondary); display: flex; align-items: center;
  gap: 5px; cursor: pointer; -webkit-user-select: none; user-select: none;
}
.options input[type="checkbox"], .options input[type="radio"] { accent-color: var(--primary); width: 16px; height: 16px; }
.options select, .options input[type="number"] {
  padding: 7px 12px; font-size: 13px; border: 1px solid var(--border); border-radius: var(--radius-sm);
  outline: none; transition: var(--transition); background: #fafbfc; font-family: inherit;
}
.options select:focus, .options input[type="number"]:focus { border-color: var(--primary); box-shadow: 0 0 0 3px rgba(37,99,235,0.08); }

.coming-soon {
  text-align: center; padding: 32px 20px; color: var(--text-secondary); font-size: 14px;
  background: var(--card-bg); border: 2px dashed var(--border); border-radius: var(--radius);
}

.no-result { display: none; text-align: center; padding: 48px 20px; color: var(--text-secondary); font-size: 15px; }

@media (max-width: 768px) {
  .main-nav { display: none; }
  .main-nav.open {
    display: flex; position: absolute; top: 60px; left: 0; right: 0;
    background: rgba(255,255,255,0.98); -webkit-backdrop-filter: blur(12px); backdrop-filter: blur(12px);
    border-bottom: 1px solid var(--border); padding: 14px 16px; gap: 8px;
    box-shadow: var(--shadow-md); animation: navSlideIn 0.2s ease-out;
  }
  @keyframes navSlideIn { from { opacity: 0; transform: translateY(-8px); } to { opacity: 1; transform: translateY(0); } }
  .nav-row { flex-wrap: wrap; }
  .nav-toggle { display: block; }
  .hero { padding: 40px 0 28px; }
  .hero h1 { font-size: 28px; }
  .tool-grid { grid-template-columns: repeat(auto-fill, minmax(160px, 1fr)); gap: 10px; }
  .tool-link { padding: 16px; }
  .tool-body .actions { flex-direction: column; }
  .tool-body .actions .btn { width: 100%; justify-content: center; }
  .back-to-top { bottom: 20px; right: 20px; width: 40px; height: 40px; }
}

@media (max-width: 480px) {
  .tool-grid { grid-template-columns: 1fr; }
  .options { flex-direction: column; align-items: flex-start; }
  .hero h1 { font-size: 24px; }
}