/* ── Reset & Base ── */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

html {
  font-family: 'Inter', system-ui, -apple-system, sans-serif;
  font-size: 15px;
  line-height: 1.6;
  color: #0f172a;
  background: #f8fafc;
  -webkit-font-smoothing: antialiased;
}

body { min-height: 100vh; }

/* ── Loading Screen ── */
.loading-screen {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  min-height: 100vh;
  gap: 16px;
}

.spinner {
  width: 40px;
  height: 40px;
  border: 3px solid #e2e8f0;
  border-top-color: #0f172a;
  border-radius: 50%;
  animation: spin 0.8s linear infinite;
}

@keyframes spin {
  to { transform: rotate(360deg); }
}

/* ── Auth UI ── */
.auth-container {
  display: flex;
  align-items: center;
  justify-content: center;
  min-height: 100vh;
  padding: 24px;
}

.auth-card {
  background: #ffffff;
  border: 1px solid #e2e8f0;
  border-radius: 8px;
  padding: 40px;
  width: 100%;
  max-width: 420px;
}

.auth-card h1 {
  font-size: 1.75rem;
  font-weight: 700;
  margin-bottom: 8px;
  text-align: center;
}

.auth-tabs {
  display: flex;
  gap: 8px;
  margin: 24px 0;
  padding: 4px;
  background: #f1f5f9;
  border-radius: 6px;
}

.auth-tab {
  flex: 1;
  padding: 10px;
  font-size: 0.875rem;
  font-weight: 500;
  border: none;
  background: transparent;
  border-radius: 4px;
  cursor: pointer;
  transition: all 0.15s;
  color: #64748b;
}

.auth-tab.active {
  background: #ffffff;
  color: #0f172a;
  box-shadow: 0 1px 2px rgba(0,0,0,0.05);
}

.auth-form {
  display: flex;
  flex-direction: column;
  gap: 16px;
}

/* ── Layout ── */
.container { max-width: 1120px; margin: 0 auto; padding: 0 32px; }
.section { padding: 48px 0; }
.stack { display: flex; flex-direction: column; gap: 16px; }
.row { display: flex; align-items: center; gap: 12px; }

/* ── Surface / Card ── */
.card {
  background: #ffffff;
  border: 1px solid #e2e8f0;
  border-radius: 6px;
  padding: 28px;
}

.card-header {
  padding-bottom: 20px;
  margin-bottom: 20px;
  border-bottom: 1px solid #e2e8f0;
}

/* ── Typography ── */
h1 { font-size: 2rem; font-weight: 700; letter-spacing: -0.03em; line-height: 1.2; }
h2 { font-size: 1.5rem; font-weight: 600; letter-spacing: -0.02em; line-height: 1.3; }
h3 { font-size: 1.1rem; font-weight: 600; letter-spacing: -0.01em; }
p { color: #64748b; line-height: 1.7; }
.text-muted { color: #64748b; font-size: 0.875rem; }
.text-subtle { color: #94a3b8; font-size: 0.8rem; }
.text-strong { font-weight: 600; color: #0f172a; }

/* ── Buttons ── */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 10px 18px;
  font-size: 0.875rem;
  font-weight: 500;
  font-family: inherit;
  border-radius: 5px;
  border: 1px solid transparent;
  cursor: pointer;
  transition: background 0.15s, border-color 0.15s, color 0.15s;
  white-space: nowrap;
  text-decoration: none;
}

.btn-primary {
  background: #0f172a;
  color: #fff;
  border-color: #0f172a;
}
.btn-primary:hover { background: #1e293b; border-color: #1e293b; }

.btn-secondary {
  background: #ffffff;
  color: #0f172a;
  border-color: #e2e8f0;
}
.btn-secondary:hover { background: #f1f5f9; }

.btn-ghost {
  background: transparent;
  color: #64748b;
  border-color: transparent;
}
.btn-ghost:hover { background: #f1f5f9; color: #0f172a; }

.btn-danger {
  background: #dc2626;
  color: #fff;
  border-color: #dc2626;
}
.btn-danger:hover { background: #b91c1c; }

.btn-sm { padding: 7px 13px; font-size: 0.8rem; }
.btn-lg { padding: 13px 24px; font-size: 1rem; width: 100%; }
.btn:disabled { opacity: 0.45; cursor: not-allowed; }

/* ── Forms ── */
.form-group { display: flex; flex-direction: column; gap: 6px; }
.form-label { font-size: 0.85rem; font-weight: 500; color: #0f172a; }

input, select, textarea {
  width: 100%;
  padding: 10px 14px;
  font-size: 0.9rem;
  font-family: inherit;
  color: #0f172a;
  background: #ffffff;
  border: 1px solid #e2e8f0;
  border-radius: 5px;
  transition: border-color 0.15s, box-shadow 0.15s;
}

input:focus, select:focus, textarea:focus {
  outline: none;
  border-color: #3b82f6;
  box-shadow: 0 0 0 3px rgba(59, 130, 246, 0.12);
}

input::placeholder, textarea::placeholder { color: #94a3b8; }

/* ── Navigation ── */
.nav {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 32px;
  height: 60px;
  background: #ffffff;
  border-bottom: 1px solid #e2e8f0;
  position: sticky;
  top: 0;
  z-index: 100;
}

.nav-brand {
  font-weight: 700;
  font-size: 1rem;
  color: #0f172a;
  letter-spacing: -0.02em;
}

.nav-links {
  display: flex;
  gap: 16px;
  align-items: center;
}

/* ── Alerts ── */
.alert {
  padding: 14px 18px;
  border-radius: 5px;
  border: 1px solid transparent;
  font-size: 0.875rem;
}

.alert-success {
  background: #f0fdf4;
  border-color: #bbf7d0;
  color: #15803d;
}

.alert-error {
  background: #fef2f2;
  border-color: #fecaca;
  color: #b91c1c;
}

/* ── Note Card ── */
.note-card {
  background: #ffffff;
  border: 1px solid #e2e8f0;
  border-radius: 6px;
  padding: 20px;
  transition: border-color 0.15s, box-shadow 0.15s;
}

.note-card:hover {
  border-color: #cbd5e1;
  box-shadow: 0 2px 4px rgba(0,0,0,0.04);
}

.note-card-header {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  margin-bottom: 12px;
}

.note-card-title {
  font-size: 1rem;
  font-weight: 600;
  color: #0f172a;
  margin-bottom: 4px;
}

.note-card-date {
  font-size: 0.75rem;
  color: #94a3b8;
}

.note-card-content {
  color: #64748b;
  line-height: 1.6;
  white-space: pre-wrap;
  margin-bottom: 16px;
}

.note-card-actions {
  display: flex;
  gap: 8px;
}

/* ── Responsive ── */
@media (max-width: 768px) {
  .container { padding: 0 16px; }
  .nav { padding: 0 16px; }
  .auth-card { padding: 28px 24px; }
  .card { padding: 20px; }
}