:root {
  --bg: #0d1117;
  --surface: #161b22;
  --border: #30363d;
  --text: #e6edf3;
  --muted: #8b949e;
  --accent: #3fb950;
  --accent-dim: #238636;
  --danger: #f85149;
  --warn: #d29922;
}

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

body {
  font-family: "Segoe UI", system-ui, sans-serif;
  background: var(--bg);
  color: var(--text);
  min-height: 100vh;
  line-height: 1.5;
}

.grid-bg {
  position: fixed;
  inset: 0;
  background-image:
    linear-gradient(rgba(63, 185, 80, 0.04) 1px, transparent 1px),
    linear-gradient(90deg, rgba(63, 185, 80, 0.04) 1px, transparent 1px);
  background-size: 32px 32px;
  pointer-events: none;
  z-index: 0;
}

.layout {
  position: relative;
  z-index: 1;
  max-width: 960px;
  margin: 0 auto;
  padding: 1.5rem;
}

.topbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  padding: 1rem 0 1.5rem;
  border-bottom: 1px solid var(--border);
  margin-bottom: 1.5rem;
}

.brand {
  display: flex;
  align-items: center;
  gap: 0.75rem;
}

.brand__icon { font-size: 1.5rem; }

.brand__title {
  font-size: 1.1rem;
  font-weight: 700;
}

.brand__sub {
  font-size: 0.8rem;
  color: var(--muted);
}

.nav {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
}

.nav a {
  color: var(--muted);
  text-decoration: none;
  padding: 0.4rem 0.75rem;
  border: 1px solid var(--border);
  border-radius: 8px;
  font-size: 0.85rem;
}

.nav a:hover,
.nav a.is-active {
  color: var(--accent);
  border-color: var(--accent-dim);
}

.card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 1.5rem;
}

.card__title {
  font-size: 1.35rem;
  margin-bottom: 0.35rem;
}

.card__sub {
  color: var(--muted);
  margin-bottom: 1.25rem;
  font-size: 0.9rem;
}

.form-label {
  display: block;
  font-size: 0.85rem;
  color: var(--muted);
  margin-bottom: 0.35rem;
}

.form-input {
  width: 100%;
  padding: 0.65rem 0.85rem;
  margin-bottom: 1rem;
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: 8px;
  color: var(--text);
  font-size: 1rem;
}

.form-input:focus {
  outline: none;
  border-color: var(--accent);
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 0.65rem 1.1rem;
  border-radius: 8px;
  border: none;
  font-size: 0.95rem;
  font-weight: 600;
  cursor: pointer;
}

.btn--primary {
  background: var(--accent);
  color: #0d1117;
}

.btn--primary:hover { background: #56d364; }

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

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

.error-msg {
  color: var(--danger);
  font-size: 0.9rem;
  margin-top: 0.75rem;
  min-height: 1.25rem;
}

.status-msg {
  margin-top: 1rem;
  padding: 0.75rem 1rem;
  border-radius: 8px;
  background: rgba(63, 185, 80, 0.12);
  border: 1px solid var(--accent-dim);
  color: var(--accent);
  font-size: 0.9rem;
  min-height: 2.75rem;
}

.welcome {
  font-size: 1.1rem;
  margin-bottom: 1rem;
}

.actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
  margin-top: 1rem;
}

.data-table {
  width: 100%;
  border-collapse: collapse;
  margin-top: 1rem;
  font-size: 0.9rem;
}

.data-table th,
.data-table td {
  border: 1px solid var(--border);
  padding: 0.65rem 0.75rem;
  text-align: left;
}

.data-table th {
  background: var(--bg);
  color: var(--muted);
  font-weight: 600;
}

.data-table button {
  padding: 0.35rem 0.65rem;
  border-radius: 6px;
  border: 1px solid var(--border);
  background: var(--bg);
  color: var(--text);
  cursor: pointer;
  font-size: 0.8rem;
  margin-right: 0.35rem;
}

.data-table button:hover {
  border-color: var(--accent);
  color: var(--accent);
}

.upload-row {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
  align-items: center;
  margin-top: 1rem;
}

.hint-box {
  margin-top: 1.5rem;
  padding: 0.85rem 1rem;
  border-radius: 8px;
  border: 1px dashed var(--border);
  color: var(--muted);
  font-size: 0.82rem;
}

.hint-box code {
  color: var(--warn);
  font-size: 0.8rem;
}

.footer-note {
  margin-top: 2rem;
  text-align: center;
  color: var(--muted);
  font-size: 0.78rem;
}

.hidden { display: none !important; }