:root {
  --primary: #4f7cff;
  --primary-dark: #3a5ed1;
  --bg: #f6f8fc;
  --card-bg: #ffffff;
  --text: #2b2f38;
  --muted: #6b7280;
  --border: #e5e7eb;
  --success: #22c55e;
  --danger: #ef4444;
  --shadow: 0 2px 12px rgba(0, 0, 0, 0.06);
}

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

html, body {
  height: 100%;
}

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

/* Header */
.navbar {
  background: #fff;
  border-bottom: 1px solid var(--border);
  padding: 0 24px;
  height: 60px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  position: sticky;
  top: 0;
  z-index: 10;
}

.navbar .logo {
  font-size: 18px;
  font-weight: 700;
  color: var(--primary);
  text-decoration: none;
}

.navbar nav {
  display: flex;
  gap: 20px;
  flex-wrap: wrap;
}

.navbar nav a {
  color: var(--text);
  text-decoration: none;
  font-size: 14px;
  padding: 6px 10px;
  border-radius: 6px;
  transition: background 0.2s, color 0.2s;
}

.navbar nav a:hover,
.navbar nav a.active {
  background: var(--primary);
  color: #fff;
}

/* Main */
main {
  flex: 1;
  width: 100%;
  max-width: 960px;
  margin: 0 auto;
  padding: 32px 20px;
}

.page-title {
  font-size: 24px;
  margin-bottom: 8px;
}

.page-desc {
  color: var(--muted);
  margin-bottom: 24px;
  font-size: 14px;
}

.card {
  background: var(--card-bg);
  border-radius: 10px;
  padding: 24px;
  box-shadow: var(--shadow);
  margin-bottom: 20px;
}

/* Footer */
footer {
  background: #fff;
  border-top: 1px solid var(--border);
  padding: 20px;
  text-align: center;
  font-size: 12px;
  color: var(--muted);
}

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

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

/* Buttons */
.btn {
  display: inline-block;
  background: var(--primary);
  color: #fff;
  border: none;
  border-radius: 6px;
  padding: 8px 18px;
  font-size: 14px;
  cursor: pointer;
  transition: background 0.2s;
}

.btn:hover {
  background: var(--primary-dark);
}

.btn.secondary {
  background: #e5e7eb;
  color: var(--text);
}

.btn.secondary:hover {
  background: #d4d7dd;
}

.btn.danger {
  background: var(--danger);
}

/* ===== Home grid ===== */
.tool-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(220px, 1fr));
  gap: 20px;
}

.tool-card {
  background: #fff;
  border-radius: 10px;
  padding: 24px;
  box-shadow: var(--shadow);
  text-decoration: none;
  color: inherit;
  transition: transform 0.2s, box-shadow 0.2s;
  display: block;
}

.tool-card:hover {
  transform: translateY(-3px);
  box-shadow: 0 6px 18px rgba(0, 0, 0, 0.08);
}

.tool-card .icon {
  font-size: 32px;
  margin-bottom: 12px;
}

.tool-card h3 {
  font-size: 16px;
  margin-bottom: 6px;
}

.tool-card p {
  font-size: 13px;
  color: var(--muted);
}

/* ===== Typing ===== */
.typing-target {
  font-size: 20px;
  line-height: 1.8;
  background: #f9fafb;
  padding: 18px;
  border-radius: 8px;
  margin-bottom: 16px;
  font-family: "Consolas", "Menlo", monospace;
  letter-spacing: 0.5px;
}

.typing-target .ok { color: var(--success); }
.typing-target .err { color: var(--danger); background: #fee2e2; }
.typing-target .cur { background: #fde68a; }

.typing-input {
  width: 100%;
  padding: 12px;
  font-size: 16px;
  border: 1px solid var(--border);
  border-radius: 6px;
  font-family: "Consolas", "Menlo", monospace;
}

.typing-stats {
  display: flex;
  gap: 24px;
  margin: 16px 0;
  flex-wrap: wrap;
}

.typing-stats .stat {
  flex: 1;
  min-width: 100px;
  text-align: center;
}

.typing-stats .stat .num {
  font-size: 22px;
  font-weight: 700;
  color: var(--primary);
}

.typing-stats .stat .label {
  font-size: 12px;
  color: var(--muted);
}

/* ===== Calculator ===== */
.calc {
  max-width: 320px;
  margin: 0 auto;
}

.calc-display {
  background: #1f2937;
  color: #fff;
  font-size: 28px;
  font-family: "Consolas", monospace;
  padding: 18px;
  border-radius: 8px;
  text-align: right;
  margin-bottom: 12px;
  min-height: 60px;
  word-break: break-all;
}

.calc-keys {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 8px;
}

.calc-keys button {
  padding: 16px;
  font-size: 18px;
  border: none;
  border-radius: 6px;
  cursor: pointer;
  background: #f3f4f6;
  transition: background 0.15s;
}

.calc-keys button:hover { background: #e5e7eb; }
.calc-keys button.op { background: #fde68a; }
.calc-keys button.op:hover { background: #fcd34d; }
.calc-keys button.eq { background: var(--primary); color: #fff; }
.calc-keys button.eq:hover { background: var(--primary-dark); }
.calc-keys button.clr { background: var(--danger); color: #fff; }
.calc-keys button.span2 { grid-column: span 2; }
.calc-keys button.eq-tall { grid-row: span 2; }

.cd-input-hidden { display: none; }

footer .copyright { margin-top: 6px; }

.beian-logo {
  height: 16px;
  width: auto;
  vertical-align: middle;
  margin-right: 4px;
}

.beian-mps {
  display: inline-flex;
  align-items: center;
}

/* ===== Timer ===== */
.timer-display {
  font-size: 56px;
  font-family: "Consolas", monospace;
  text-align: center;
  padding: 24px;
  background: #f9fafb;
  border-radius: 8px;
  margin-bottom: 20px;
  letter-spacing: 2px;
}

.timer-mode {
  display: flex;
  gap: 10px;
  justify-content: center;
  margin-bottom: 16px;
}

.timer-input {
  display: flex;
  gap: 8px;
  justify-content: center;
  margin-bottom: 16px;
  flex-wrap: wrap;
}

.timer-input input {
  width: 70px;
  padding: 8px;
  font-size: 16px;
  border: 1px solid var(--border);
  border-radius: 6px;
  text-align: center;
}

.timer-controls {
  display: flex;
  gap: 10px;
  justify-content: center;
}

/* ===== Todo ===== */
.todo-form {
  display: flex;
  gap: 8px;
  margin-bottom: 16px;
}

.todo-form input {
  flex: 1;
  padding: 10px 12px;
  font-size: 14px;
  border: 1px solid var(--border);
  border-radius: 6px;
}

.todo-list {
  list-style: none;
}

.todo-item {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 10px 12px;
  border: 1px solid var(--border);
  border-radius: 6px;
  margin-bottom: 8px;
  background: #fff;
}

.todo-item input[type="checkbox"] {
  width: 18px;
  height: 18px;
  cursor: pointer;
}

.todo-item .text {
  flex: 1;
  font-size: 14px;
}

.todo-item.done .text {
  text-decoration: line-through;
  color: var(--muted);
}

.todo-item .del {
  background: transparent;
  border: none;
  color: var(--danger);
  cursor: pointer;
  font-size: 18px;
  padding: 4px 8px;
}

.todo-empty {
  text-align: center;
  color: var(--muted);
  padding: 24px;
  font-size: 14px;
}

/* Responsive */
@media (max-width: 600px) {
  .navbar {
    padding: 0 12px;
    height: auto;
    flex-direction: column;
    gap: 8px;
    padding: 10px 12px;
  }
  .navbar nav { gap: 6px; }
  .navbar nav a { font-size: 13px; padding: 4px 8px; }
  main { padding: 20px 14px; }
  .timer-display { font-size: 40px; }
}