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

:root {
  --bg: #0f1117;
  --surface: #1a1d27;
  --surface2: #232636;
  --border: #2e3148;
  --accent: #6c63ff;
  --accent2: #00d4aa;
  --text: #e2e4f0;
  --text-muted: #7a7f9a;
  --danger: #ff5252;
  --success: #00c97b;
  --radius: 10px;
  --font: 'Segoe UI', system-ui, sans-serif;
  --mono: 'Cascadia Code', 'Fira Code', Consolas, monospace;
}

body {
  background: var(--bg);
  color: var(--text);
  font-family: var(--font);
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

.container {
  max-width: 900px;
  margin: 0 auto;
  padding: 0 20px;
}

/* Header */
.header {
  background: var(--surface);
  border-bottom: 1px solid var(--border);
  padding: 14px 0;
  position: sticky;
  top: 0;
  z-index: 100;
}

.header .container {
  display: flex;
  align-items: center;
  gap: 32px;
}

.logo {
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--accent);
  text-decoration: none;
  letter-spacing: -0.5px;
  flex-shrink: 0;
}

.nav {
  display: flex;
  gap: 4px;
  flex-wrap: wrap;
}

.nav-link {
  color: var(--text-muted);
  text-decoration: none;
  padding: 6px 14px;
  border-radius: 6px;
  font-size: 0.9rem;
  transition: color 0.2s, background 0.2s;
}

.nav-link:hover,
.nav-link.active {
  color: var(--text);
  background: var(--surface2);
}

.nav-link.active {
  color: var(--accent);
}

/* Main */
.main {
  flex: 1;
  padding: 40px 20px;
}

/* Home grid */
.home-title {
  font-size: 2rem;
  font-weight: 700;
  margin-bottom: 8px;
  background: linear-gradient(135deg, var(--accent), var(--accent2));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.home-sub {
  color: var(--text-muted);
  margin-bottom: 36px;
  font-size: 1.05rem;
}

.tools-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(240px, 1fr));
  gap: 16px;
}

.tool-card {
  display: block;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 24px 20px;
  text-decoration: none;
  color: inherit;
  transition: border-color 0.2s, transform 0.15s, box-shadow 0.2s;
  cursor: pointer;
}

.tool-card:hover {
  border-color: var(--accent);
  transform: translateY(-2px);
  box-shadow: 0 8px 24px rgba(108, 99, 255, 0.12);
}

.tool-card-icon {
  font-size: 2rem;
  margin-bottom: 12px;
}

.tool-card-title {
  font-size: 1.05rem;
  font-weight: 600;
  margin-bottom: 6px;
}

.tool-card-desc {
  font-size: 0.85rem;
  color: var(--text-muted);
  line-height: 1.5;
}

/* Tool page */
.tool-header {
  margin-bottom: 28px;
}

.tool-back {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  color: var(--text-muted);
  text-decoration: none;
  font-size: 0.9rem;
  margin-bottom: 16px;
  transition: color 0.2s;
}

.tool-back:hover { color: var(--text); }

.tool-title {
  font-size: 1.6rem;
  font-weight: 700;
  margin-bottom: 4px;
}

.tool-desc {
  color: var(--text-muted);
  font-size: 0.95rem;
}

/* Card / panel */
.card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 24px;
  margin-bottom: 16px;
}

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 9px 18px;
  border-radius: 7px;
  border: none;
  cursor: pointer;
  font-size: 0.9rem;
  font-family: inherit;
  font-weight: 500;
  transition: opacity 0.15s, transform 0.1s;
}

.btn:active { transform: scale(0.97); }

.btn-primary {
  background: var(--accent);
  color: #fff;
}

.btn-secondary {
  background: var(--surface2);
  color: var(--text);
  border: 1px solid var(--border);
}

.btn-danger {
  background: transparent;
  color: var(--danger);
  border: 1px solid var(--danger);
}

.btn-success {
  background: var(--success);
  color: #000;
}

.btn:hover { opacity: 0.88; }

.btn-group {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-top: 14px;
}

/* Inputs */
textarea, input[type="text"], input[type="number"], select {
  width: 100%;
  background: var(--surface2);
  border: 1px solid var(--border);
  border-radius: 7px;
  color: var(--text);
  font-family: var(--mono);
  font-size: 0.88rem;
  padding: 10px 14px;
  outline: none;
  transition: border-color 0.2s;
  resize: vertical;
}

textarea:focus, input[type="text"]:focus, input[type="number"]:focus, select:focus {
  border-color: var(--accent);
}

label {
  display: block;
  font-size: 0.82rem;
  color: var(--text-muted);
  margin-bottom: 6px;
  font-weight: 500;
  letter-spacing: 0.3px;
}

.field { margin-bottom: 16px; }

/* UUID */
.uuid-list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 8px;
  margin-top: 16px;
}

.uuid-item {
  display: flex;
  align-items: center;
  gap: 10px;
  background: var(--surface2);
  border: 1px solid var(--border);
  border-radius: 7px;
  padding: 10px 14px;
  font-family: var(--mono);
  font-size: 0.9rem;
}

.uuid-item span { flex: 1; word-break: break-all; }

.uuid-copy-btn {
  background: transparent;
  border: none;
  cursor: pointer;
  color: var(--text-muted);
  font-size: 1rem;
  padding: 2px 6px;
  border-radius: 4px;
  transition: color 0.2s, background 0.2s;
  flex-shrink: 0;
}

.uuid-copy-btn:hover { color: var(--accent); background: var(--surface); }

/* Options row */
.options-row {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 16px;
  margin-bottom: 16px;
}

.option-item {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 0.9rem;
  color: var(--text-muted);
}

.option-item input[type="checkbox"] { width: auto; accent-color: var(--accent); }
.option-item input[type="number"] { width: 70px; }

/* Converter tabs */
.tabs {
  display: flex;
  gap: 4px;
  margin-bottom: 20px;
  border-bottom: 1px solid var(--border);
  padding-bottom: 0;
}

.tab {
  padding: 8px 16px;
  border-radius: 7px 7px 0 0;
  border: none;
  background: transparent;
  color: var(--text-muted);
  cursor: pointer;
  font-family: inherit;
  font-size: 0.9rem;
  border-bottom: 2px solid transparent;
  transition: color 0.2s;
  margin-bottom: -1px;
}

.tab.active {
  color: var(--accent);
  border-bottom-color: var(--accent);
}

.tab:hover:not(.active) { color: var(--text); }

/* JSON status */
.status-bar {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 10px 14px;
  border-radius: 7px;
  font-size: 0.88rem;
  margin-top: 12px;
}

.status-bar.valid   { background: rgba(0, 201, 123, 0.1); border: 1px solid rgba(0, 201, 123, 0.3); color: var(--success); }
.status-bar.invalid { background: rgba(255, 82, 82, 0.1);  border: 1px solid rgba(255, 82, 82, 0.3);  color: var(--danger); }
.status-bar.idle    { background: var(--surface2); border: 1px solid var(--border); color: var(--text-muted); }

.dot {
  width: 8px; height: 8px;
  border-radius: 50%;
  flex-shrink: 0;
}

.valid .dot   { background: var(--success); }
.invalid .dot { background: var(--danger); }
.idle .dot    { background: var(--text-muted); }

/* Two-col layout */
.two-col {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 16px;
}

@media (max-width: 600px) {
  .two-col { grid-template-columns: 1fr; }
  .home-title { font-size: 1.5rem; }
  .tool-title { font-size: 1.3rem; }
}

/* Toast */
.toast {
  position: fixed;
  bottom: 24px;
  right: 24px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 12px 18px;
  font-size: 0.88rem;
  box-shadow: 0 8px 32px rgba(0,0,0,0.4);
  z-index: 9999;
  animation: slideIn 0.2s ease;
}

@keyframes slideIn {
  from { opacity: 0; transform: translateY(10px); }
  to   { opacity: 1; transform: translateY(0); }
}

/* Misc */
.mt8  { margin-top: 8px; }
.mt16 { margin-top: 16px; }
pre.output {
  background: var(--surface2);
  border: 1px solid var(--border);
  border-radius: 7px;
  padding: 14px;
  overflow: auto;
  font-family: var(--mono);
  font-size: 0.85rem;
  white-space: pre-wrap;
  word-break: break-word;
  max-height: 320px;
}