:root {
  --primary: #2563eb;
  --primary-hover: #1d4ed8;
  --primary-light: #eff6ff;
  --bg: #f1f5f9;
  --surface: #ffffff;
  --text: #0f172a;
  --text-secondary: #475569;
  --text-muted: #94a3b8;
  --border: #e2e8f0;
  --border-hover: #cbd5e1;
  --success: #10b981;
  --success-light: #ecfdf5;
  --warning: #f59e0b;
  --warning-light: #fffbeb;
  --danger: #ef4444;
  --danger-light: #fef2f2;
  --radius: 8px;
  --radius-sm: 6px;
  --shadow: 0 1px 3px rgba(0,0,0,0.08), 0 1px 2px rgba(0,0,0,0.06);
  --shadow-md: 0 4px 6px rgba(0,0,0,0.07), 0 2px 4px rgba(0,0,0,0.06);
}

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

body {
  font-family: 'Noto Sans JP', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
  min-height: 100vh;
}

/* Login Page */
.login-wrapper {
  display: flex;
  align-items: center;
  justify-content: center;
  min-height: 100vh;
  padding: 1rem;
}

.login-card {
  background: var(--surface);
  border-radius: 12px;
  box-shadow: var(--shadow-md);
  padding: 2.5rem;
  width: 100%;
  max-width: 400px;
}

.login-card h1 {
  font-size: 1.5rem;
  font-weight: 700;
  margin-bottom: 0.25rem;
  color: var(--text);
}

.login-card .subtitle {
  color: var(--text-muted);
  font-size: 0.875rem;
  margin-bottom: 2rem;
}

/* Header */
.header {
  background: var(--surface);
  border-bottom: 1px solid var(--border);
  padding: 0 1.5rem;
  height: 56px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  position: sticky;
  top: 0;
  z-index: 100;
}

.header-left {
  display: flex;
  align-items: center;
  gap: 1rem;
}

.header-logo {
  font-size: 1.125rem;
  font-weight: 700;
  color: var(--primary);
}

.header-right {
  display: flex;
  align-items: center;
  gap: 1rem;
}

.header-user {
  font-size: 0.875rem;
  color: var(--text-secondary);
}

/* Navigation Tabs */
.nav-tabs {
  background: var(--surface);
  border-bottom: 1px solid var(--border);
  display: flex;
  gap: 0;
  padding: 0 1.5rem;
  overflow-x: auto;
}

.nav-tab {
  padding: 0.75rem 1.25rem;
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--text-secondary);
  border: none;
  background: none;
  cursor: pointer;
  border-bottom: 2px solid transparent;
  white-space: nowrap;
  transition: color 0.15s, border-color 0.15s;
}

.nav-tab:hover { color: var(--text); }
.nav-tab.active {
  color: var(--primary);
  border-bottom-color: var(--primary);
}

/* Main Content */
.main { padding: 1.5rem; max-width: 1200px; margin: 0 auto; }

/* Cards */
.card {
  background: var(--surface);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 1.5rem;
  margin-bottom: 1rem;
}

.card-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 1rem;
}

.card-title {
  font-size: 1rem;
  font-weight: 600;
}

/* Stats Grid */
.stats-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 1rem;
  margin-bottom: 1.5rem;
}

.stat-card {
  background: var(--surface);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 1.25rem;
}

.stat-label {
  font-size: 0.75rem;
  font-weight: 500;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  margin-bottom: 0.25rem;
}

.stat-value {
  font-size: 1.75rem;
  font-weight: 700;
  color: var(--text);
}

.stat-unit {
  font-size: 0.875rem;
  font-weight: 400;
  color: var(--text-secondary);
  margin-left: 0.25rem;
}

/* Progress Bar */
.progress-wrap { margin-top: 0.75rem; }

.progress-bar-bg {
  height: 8px;
  background: var(--bg);
  border-radius: 4px;
  overflow: hidden;
}

.progress-bar-fill {
  height: 100%;
  border-radius: 4px;
  background: var(--primary);
  transition: width 0.4s ease;
}

.progress-bar-fill.warning { background: var(--warning); }
.progress-bar-fill.danger { background: var(--danger); }
.progress-bar-fill.success { background: var(--success); }

.progress-label {
  display: flex;
  justify-content: space-between;
  font-size: 0.75rem;
  color: var(--text-secondary);
  margin-top: 0.25rem;
}

/* Contract Cards */
.contract-list { display: grid; gap: 1rem; }

.contract-card {
  background: var(--surface);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 1.25rem;
  cursor: pointer;
  transition: box-shadow 0.15s, transform 0.15s;
  border: 1px solid var(--border);
}

.contract-card:hover {
  box-shadow: var(--shadow-md);
  transform: translateY(-1px);
}

.contract-card-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 0.75rem;
}

.contract-card-title {
  font-weight: 600;
  font-size: 0.9375rem;
}

.contract-card-meta {
  font-size: 0.8125rem;
  color: var(--text-secondary);
  display: flex;
  gap: 1rem;
  margin-bottom: 0.5rem;
}

/* Badge */
.badge {
  display: inline-flex;
  align-items: center;
  padding: 0.125rem 0.625rem;
  border-radius: 9999px;
  font-size: 0.75rem;
  font-weight: 500;
}

.badge-active { background: var(--success-light); color: var(--success); }
.badge-completed { background: var(--primary-light); color: var(--primary); }
.badge-cancelled { background: var(--bg); color: var(--text-muted); }
.badge-time { background: var(--primary-light); color: var(--primary); }
.badge-deliverable { background: var(--warning-light); color: #b45309; }
.badge-pending { background: var(--warning-light); color: #b45309; }
.badge-in_progress { background: var(--primary-light); color: var(--primary); }
.badge-submitted { background: var(--warning-light); color: #b45309; }
.badge-approved { background: var(--success-light); color: var(--success); }
.badge-rejected { background: var(--danger-light); color: var(--danger); }
.badge-draft { background: var(--bg); color: var(--text-muted); }

/* Forms */
.form-group { margin-bottom: 1rem; }

.form-label {
  display: block;
  font-size: 0.8125rem;
  font-weight: 500;
  color: var(--text-secondary);
  margin-bottom: 0.375rem;
}

.form-input, .form-select, .form-textarea {
  width: 100%;
  padding: 0.5rem 0.75rem;
  font-size: 0.875rem;
  font-family: inherit;
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  background: var(--surface);
  color: var(--text);
  transition: border-color 0.15s;
}

.form-input:focus, .form-select:focus, .form-textarea:focus {
  outline: none;
  border-color: var(--primary);
  box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.1);
}

.form-textarea { resize: vertical; min-height: 80px; }

.form-row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1rem;
}

.form-error {
  color: var(--danger);
  font-size: 0.8125rem;
  margin-top: 0.5rem;
}

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.375rem;
  padding: 0.5rem 1rem;
  font-size: 0.875rem;
  font-family: inherit;
  font-weight: 500;
  border: 1px solid transparent;
  border-radius: var(--radius-sm);
  cursor: pointer;
  transition: background 0.15s, border-color 0.15s, opacity 0.15s;
}

.btn:disabled { opacity: 0.5; cursor: not-allowed; }

.btn-primary {
  background: var(--primary);
  color: #fff;
}
.btn-primary:hover:not(:disabled) { background: var(--primary-hover); }

.btn-secondary {
  background: var(--surface);
  color: var(--text);
  border-color: var(--border);
}
.btn-secondary:hover:not(:disabled) { background: var(--bg); border-color: var(--border-hover); }

.btn-danger {
  background: var(--danger);
  color: #fff;
}
.btn-danger:hover:not(:disabled) { background: #dc2626; }

.btn-success {
  background: var(--success);
  color: #fff;
}
.btn-success:hover:not(:disabled) { background: #059669; }

.btn-ghost {
  background: transparent;
  color: var(--text-secondary);
}
.btn-ghost:hover:not(:disabled) { background: var(--bg); color: var(--text); }

.btn-sm { padding: 0.25rem 0.625rem; font-size: 0.8125rem; }

.btn-block { width: 100%; }

.btn-group { display: flex; gap: 0.5rem; }

/* Tables */
.table-wrap { overflow-x: auto; }

table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.875rem;
}

th {
  text-align: left;
  padding: 0.625rem 0.75rem;
  font-weight: 500;
  color: var(--text-secondary);
  border-bottom: 1px solid var(--border);
  font-size: 0.8125rem;
  white-space: nowrap;
}

td {
  padding: 0.625rem 0.75rem;
  border-bottom: 1px solid var(--border);
  vertical-align: middle;
}

tr:last-child td { border-bottom: none; }

tr:hover td { background: var(--bg); }

/* Modal */
.modal-overlay {
  position: fixed;
  inset: 0;
  background: rgba(0,0,0,0.4);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 200;
  padding: 1rem;
  opacity: 0;
  visibility: hidden;
  transition: opacity 0.2s, visibility 0.2s;
}

.modal-overlay.active { opacity: 1; visibility: visible; }

.modal {
  background: var(--surface);
  border-radius: 12px;
  box-shadow: 0 20px 60px rgba(0,0,0,0.15);
  width: 100%;
  max-width: 560px;
  max-height: 90vh;
  overflow-y: auto;
  transform: translateY(10px);
  transition: transform 0.2s;
}

.modal-overlay.active .modal { transform: translateY(0); }

.modal-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 1.25rem 1.5rem;
  border-bottom: 1px solid var(--border);
}

.modal-title { font-size: 1.0625rem; font-weight: 600; }

.modal-close {
  background: none;
  border: none;
  font-size: 1.25rem;
  color: var(--text-muted);
  cursor: pointer;
  padding: 0.25rem;
  line-height: 1;
}
.modal-close:hover { color: var(--text); }

.modal-body { padding: 1.5rem; }

.modal-footer {
  display: flex;
  justify-content: flex-end;
  gap: 0.5rem;
  padding: 1rem 1.5rem;
  border-top: 1px solid var(--border);
}

/* Month Selector */
.month-selector {
  display: flex;
  align-items: center;
  gap: 0.75rem;
}

.month-selector .month-display {
  font-size: 1rem;
  font-weight: 600;
  min-width: 120px;
  text-align: center;
}

.month-btn {
  background: none;
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 0.25rem 0.5rem;
  cursor: pointer;
  color: var(--text-secondary);
  font-size: 1rem;
  line-height: 1;
}
.month-btn:hover { background: var(--bg); }

/* Empty State */
.empty-state {
  text-align: center;
  padding: 3rem 1rem;
  color: var(--text-muted);
}

.empty-state p { font-size: 0.875rem; margin-top: 0.5rem; }

/* Section */
.section-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 1rem;
}

.section-title {
  font-size: 1.0625rem;
  font-weight: 600;
}

/* Detail View */
.detail-back {
  display: inline-flex;
  align-items: center;
  gap: 0.375rem;
  font-size: 0.875rem;
  color: var(--text-secondary);
  text-decoration: none;
  cursor: pointer;
  margin-bottom: 1rem;
  background: none;
  border: none;
  font-family: inherit;
}
.detail-back:hover { color: var(--primary); }

.detail-title {
  font-size: 1.25rem;
  font-weight: 700;
  margin-bottom: 0.25rem;
}

.detail-meta {
  font-size: 0.8125rem;
  color: var(--text-secondary);
  display: flex;
  gap: 1.5rem;
  flex-wrap: wrap;
  margin-bottom: 1.5rem;
}

/* Invoice */
.invoice-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1rem 1.25rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 0.75rem;
}

.invoice-info { flex: 1; }
.invoice-title { font-weight: 500; font-size: 0.9375rem; }
.invoice-meta { font-size: 0.8125rem; color: var(--text-secondary); margin-top: 0.125rem; }
.invoice-amount { font-size: 1.125rem; font-weight: 600; margin-right: 1rem; }
.invoice-actions { display: flex; gap: 0.5rem; align-items: center; }

/* Tabs inside card */
.inner-tabs {
  display: flex;
  gap: 0;
  border-bottom: 1px solid var(--border);
  margin: -1.5rem -1.5rem 1.5rem;
  padding: 0 1.5rem;
}

.inner-tab {
  padding: 0.75rem 1rem;
  font-size: 0.8125rem;
  font-weight: 500;
  color: var(--text-secondary);
  border: none;
  background: none;
  cursor: pointer;
  border-bottom: 2px solid transparent;
}
.inner-tab:hover { color: var(--text); }
.inner-tab.active { color: var(--primary); border-bottom-color: var(--primary); }

/* Timer Bar */
.timer-bar {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 0.875rem 1.25rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 1.5rem;
  gap: 1rem;
}

.timer-bar-left {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  flex-wrap: wrap;
}

.timer-bar-active {
  background: linear-gradient(135deg, #fef2f2, #fff1f2);
  border-color: #fecaca;
  animation: timer-pulse 2s ease-in-out infinite;
}

@keyframes timer-pulse {
  0%, 100% { box-shadow: 0 0 0 0 rgba(239, 68, 68, 0); }
  50% { box-shadow: 0 0 0 4px rgba(239, 68, 68, 0.08); }
}

.timer-display {
  font-size: 2rem;
  font-weight: 700;
  font-variant-numeric: tabular-nums;
  color: var(--danger);
  letter-spacing: 0.02em;
}

.timer-meta {
  display: flex;
  flex-direction: column;
  gap: 0.125rem;
  font-size: 0.8125rem;
  color: var(--text-secondary);
}

.timer-stop-summary {
  display: flex;
  gap: 1rem;
}

.timer-stop-summary .stat-card {
  flex: 1;
  text-align: center;
}

/* Utility */
.text-right { text-align: right; }
.text-center { text-align: center; }
.text-muted { color: var(--text-muted); }
.text-sm { font-size: 0.8125rem; }
.mt-1 { margin-top: 0.5rem; }
.mt-2 { margin-top: 1rem; }
.mb-1 { margin-bottom: 0.5rem; }
.mb-2 { margin-bottom: 1rem; }
.flex { display: flex; }
.items-center { align-items: center; }
.gap-1 { gap: 0.5rem; }
.gap-2 { gap: 1rem; }
.hidden { display: none !important; }

/* Responsive */
@media (max-width: 640px) {
  .main { padding: 1rem; }
  .form-row { grid-template-columns: 1fr; }
  .stats-grid { grid-template-columns: 1fr 1fr; }
  .contract-card-meta { flex-direction: column; gap: 0.25rem; }
  .invoice-card { flex-direction: column; align-items: flex-start; gap: 0.75rem; }
  .invoice-actions { width: 100%; }
  .header { padding: 0 1rem; }
  .nav-tabs { padding: 0 1rem; }
  .detail-meta { flex-direction: column; gap: 0.5rem; }
  .modal { max-width: 100%; }
  .timer-bar { flex-direction: column; align-items: stretch; }
  .timer-bar-left { flex-direction: column; }
  .timer-display { font-size: 1.5rem; }
}