/* ===== 全局 ===== */
:root {
  --bg: #f5f7fa;
  --card: #ffffff;
  --primary: #4f46e5;
  --primary-hover: #4338ca;
  --text: #1e293b;
  --text-secondary: #64748b;
  --border: #e2e8f0;
  --radius: 12px;
  --shadow: 0 1px 3px rgba(0,0,0,.08), 0 1px 2px rgba(0,0,0,.04);
  --shadow-lg: 0 4px 12px rgba(0,0,0,.1);
  --success: #22c55e;
  --error: #ef4444;
  --font: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Noto Sans SC", sans-serif;
}

[data-theme="dark"] {
  --bg: #0f172a;
  --card: #1e293b;
  --text: #f1f5f9;
  --text-secondary: #94a3b8;
  --border: #334155;
  --shadow: 0 1px 3px rgba(0,0,0,.3);
  --shadow-lg: 0 4px 12px rgba(0,0,0,.4);
}

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

body {
  font-family: var(--font);
  background: var(--bg);
  color: var(--text);
  min-height: 100vh;
  transition: background .3s, color .3s;
}

/* ===== 顶部导航 ===== */
header {
  background: var(--card);
  border-bottom: 1px solid var(--border);
  position: sticky;
  top: 0;
  z-index: 100;
  backdrop-filter: blur(8px);
  background: rgba(255,255,255,.85);
}
[data-theme="dark"] header {
  background: rgba(30,41,59,.85);
}
.header-inner {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 20px;
  height: 60px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}
.logo {
  font-size: 20px;
  font-weight: 700;
  color: var(--primary);
  text-decoration: none;
  display: flex;
  align-items: center;
  gap: 8px;
}
.logo span { font-size: 24px; }
nav {
  display: flex;
  align-items: center;
  gap: 16px;
}
.theme-toggle {
  background: none;
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 6px 12px;
  cursor: pointer;
  color: var(--text);
  font-size: 16px;
  transition: all .2s;
}
.theme-toggle:hover {
  border-color: var(--primary);
  color: var(--primary);
}

/* ===== 主体 ===== */
main {
  max-width: 1200px;
  margin: 0 auto;
  padding: 24px 20px 60px;
}

/* ===== 搜索/筛选 ===== */
.tool-search {
  margin-bottom: 24px;
}
.tool-search input {
  width: 100%;
  padding: 12px 16px;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  background: var(--card);
  color: var(--text);
  font-size: 15px;
  outline: none;
  transition: border .2s;
}
.tool-search input:focus {
  border-color: var(--primary);
  box-shadow: 0 0 0 3px rgba(79,70,229,.15);
}
.tool-search input::placeholder { color: var(--text-secondary); }

/* ===== 工具网格 ===== */
.tool-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 16px;
  margin-bottom: 32px;
}

.tool-card {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 20px;
  cursor: pointer;
  transition: all .2s;
  box-shadow: var(--shadow);
}
.tool-card:hover {
  border-color: var(--primary);
  box-shadow: var(--shadow-lg);
  transform: translateY(-2px);
}
.tool-card .icon {
  font-size: 28px;
  margin-bottom: 10px;
}
.tool-card h3 {
  font-size: 16px;
  margin-bottom: 6px;
}
.tool-card p {
  font-size: 13px;
  color: var(--text-secondary);
  line-height: 1.5;
}

/* ===== 工具面板 ===== */
.tool-panel {
  display: none;
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 28px;
  box-shadow: var(--shadow-lg);
  margin-bottom: 24px;
}
.tool-panel.active { display: block; }

.tool-panel-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 20px;
  padding-bottom: 16px;
  border-bottom: 1px solid var(--border);
}
.tool-panel-header h2 {
  font-size: 20px;
  display: flex;
  align-items: center;
  gap: 8px;
}
.tool-panel-header .close-btn {
  background: none;
  border: none;
  font-size: 22px;
  color: var(--text-secondary);
  cursor: pointer;
  padding: 4px 8px;
  border-radius: 6px;
  transition: all .2s;
}
.tool-panel-header .close-btn:hover {
  background: var(--border);
  color: var(--text);
}

/* ===== 工具表单 ===== */
.tool-body { margin-bottom: 12px; }
.tool-body label {
  display: block;
  font-size: 14px;
  font-weight: 600;
  margin-bottom: 6px;
  color: var(--text);
}
.tool-body textarea,
.tool-body input[type="text"],
.tool-body input[type="number"],
.tool-body select {
  width: 100%;
  padding: 10px 14px;
  border: 1px solid var(--border);
  border-radius: 8px;
  background: var(--bg);
  color: var(--text);
  font-size: 14px;
  font-family: 'SF Mono', 'Fira Code', monospace;
  outline: none;
  transition: border .2s;
  resize: vertical;
}
.tool-body textarea:focus,
.tool-body input:focus,
.tool-body select:focus {
  border-color: var(--primary);
  box-shadow: 0 0 0 3px rgba(79,70,229,.12);
}
.tool-body textarea {
  min-height: 120px;
  font-size: 13px;
  line-height: 1.6;
}

.btn-row {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
  margin: 12px 0;
}
.btn {
  padding: 8px 18px;
  border: none;
  border-radius: 8px;
  font-size: 14px;
  font-weight: 600;
  cursor: pointer;
  transition: all .2s;
}
.btn-primary {
  background: var(--primary);
  color: #fff;
}
.btn-primary:hover { background: var(--primary-hover); }
.btn-outline {
  background: transparent;
  border: 1px solid var(--border);
  color: var(--text);
}
.btn-outline:hover { border-color: var(--primary); color: var(--primary); }
.btn-success {
  background: var(--success);
  color: #fff;
}
.btn-success:hover { opacity: .9; }
.btn-sm { padding: 5px 12px; font-size: 13px; }

.result-area {
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 14px;
  font-size: 13px;
  font-family: 'SF Mono', 'Fira Code', monospace;
  line-height: 1.6;
  overflow-x: auto;
  white-space: pre-wrap;
  word-break: break-all;
  min-height: 40px;
  max-height: 400px;
  overflow-y: auto;
  margin-top: 8px;
}
.result-area.error {
  color: var(--error);
}
.copy-btn {
  position: relative;
}

/* ===== 页脚 ===== */
footer {
  text-align: center;
  padding: 32px 20px;
  color: var(--text-secondary);
  font-size: 13px;
  border-top: 1px solid var(--border);
}
footer a { color: var(--primary); text-decoration: none; }

/* ===== Ad 占位 ===== */
.ad-container {
  background: var(--card);
  border: 1px dashed var(--border);
  border-radius: var(--radius);
  padding: 20px;
  text-align: center;
  color: var(--text-secondary);
  font-size: 13px;
  margin: 24px 0;
  min-height: 90px;
  display: flex;
  align-items: center;
  justify-content: center;
}

/* ===== 响应式 ===== */
@media (max-width: 640px) {
  .header-inner { padding: 0 14px; }
  main { padding: 16px 14px 40px; }
  .tool-grid { grid-template-columns: 1fr; }
  .tool-panel { padding: 18px; }
  .btn-row { flex-direction: column; }
  .btn { width: 100%; text-align: center; }
}