:root {
  --bg-main: #F4F4EB;
  --bg-surface: #FFFFFF;
  --text-main: #111111;
  --text-muted: #666666;
  --border: #D1D1C7;
  --border-strong: #111111;
  --accent: #E53935;
  
  --depth-1: #D1D1C7;
  --depth-2: #999999;
  --depth-3: #555555;
  --depth-4: #222222;
  --depth-5: #E53935;
  
  --font-display: 'Bricolage Grotesque', sans-serif;
  --font-body: 'DM Sans', sans-serif;
  
  --ease-out: cubic-bezier(0.16, 1, 0.3, 1);
  --ease-fluid: cubic-bezier(0.77, 0, 0.175, 1);
}

* { margin: 0; padding: 0; box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  background-color: var(--bg-main);
  color: var(--text-main);
  font-family: var(--font-body);
  line-height: 1.5;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  text-rendering: optimizeLegibility;
  padding-bottom: 5rem;
}

.app-container {
  max-width: 1280px;
  margin: 0 auto;
  padding: 4rem 2rem;
}

/* Header */
.app-header {
  border-bottom: 2px solid var(--border-strong);
  padding-bottom: 2rem;
  margin-bottom: 3rem;
  animation: fadeUp 0.8s var(--ease-out);
}

.subtitle {
  font-size: 1.15rem;
  color: var(--text-muted);
  font-weight: 500;
}

.header-content {
  display: flex;
  justify-content: space-between;
  align-items: flex-end;
  gap: 2rem;
  flex-wrap: wrap;
  margin-bottom: 3rem;
}

h1 {
  font-family: var(--font-display);
  font-size: clamp(3rem, 6vw, 5.5rem);
  font-weight: 800;
  letter-spacing: -0.04em;
  line-height: 1.05;
  text-transform: uppercase;
  margin: 0.5rem 0;
}

/* Progress bar */
.progress-container {
  width: 100%;
  max-width: 250px;
}

.progress-info {
  display: flex;
  justify-content: space-between;
  font-family: var(--font-display);
  font-weight: 800;
  font-size: 1rem;
  text-transform: uppercase;
  margin-bottom: 0.5rem;
}

.progress-bar-bg {
  height: 2px;
  background-color: var(--border);
  position: relative;
}

.progress-bar-fill {
  position: absolute;
  top: -1px; left: 0;
  height: 4px;
  background-color: var(--text-main);
  transition: width 0.8s var(--ease-fluid);
}

/* Controls */
.controls-bar {
  display: flex;
  gap: 1rem;
  margin-bottom: 3rem;
  animation: fadeUp 0.8s var(--ease-out) 0.1s backwards;
}

.btn {
  font-family: var(--font-display);
  background: transparent;
  color: var(--text-main);
  border: 1px solid var(--border-strong);
  padding: 0.75rem 1.25rem;
  font-size: 0.9rem;
  font-weight: 800;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  cursor: pointer;
  transition: transform 150ms var(--ease-out), background 150ms var(--ease-out), color 150ms var(--ease-out);
}

.btn:hover {
  background: var(--text-main);
  color: var(--bg-main);
}

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

.btn.danger:hover {
  background: var(--accent);
  border-color: var(--accent);
  color: #fff;
}

/* Depth Scale */
.depth-wrapper {
  display: flex;
  align-items: center;
  gap: 1.5rem;
  font-family: var(--font-display);
  text-transform: uppercase;
  font-size: 0.85rem;
  font-weight: 700;
}

.depth-legend { display: flex; align-items: center; gap: 0.5rem; }

.depth-dot {
  width: 12px; height: 12px;
}

/* Stages */
.roadmap-container {
  display: flex;
  flex-direction: column;
  gap: 2rem;
}

.stage-card {
  border: 1px solid var(--border);
  background: var(--bg-surface);
  transition: border-color 0.3s ease;
  transform: translateZ(0);
  will-change: border-color;
}

.stage-card:hover { border-color: var(--text-main); }

.stage-header {
  display: flex;
  align-items: center;
  padding: 2rem;
  cursor: pointer;
  user-select: none;
  background: var(--bg-surface);
  position: relative;
}

.stage-dot {
  font-family: var(--font-display);
  font-size: 3.5rem;
  font-weight: 800;
  color: var(--border);
  width: 90px;
  transition: color 250ms var(--ease-out);
  line-height: 0.8;
  letter-spacing: -0.05em;
}

.stage-card:hover .stage-dot { color: var(--text-main); }

.stage-info { flex: 1; }

.stage-title {
  font-family: var(--font-display);
  font-size: 2.25rem;
  font-weight: 800;
  letter-spacing: -0.03em;
  display: flex;
  align-items: center;
  margin-bottom: 0.5rem;
}

.chevron {
  display: inline-block;
  margin-left: 1rem;
  font-weight: 400;
  transition: transform 400ms var(--ease-fluid);
}

.collapsed .chevron { transform: rotate(-90deg); }

.stage-meta {
  display: flex;
  align-items: center;
  gap: 1rem;
}

.badge {
  font-size: 0.75rem;
  text-transform: uppercase;
  font-weight: 800;
  padding: 0.2rem 0.6rem;
  border: 1px solid var(--border-strong);
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.badge div { width: 8px; height: 8px; }

.rationale {
  color: var(--text-muted);
  font-size: 1rem;
}

/* Sections Grid */
.sections-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(440px, 1fr));
  border-top: 1px solid var(--border);
  overflow: hidden;
  transition: max-height 500ms var(--ease-fluid);
  will-change: max-height;
  transform: translateZ(0);
}

.section-card {
  padding: 2.5rem 2rem;
  border-right: 1px solid var(--border);
  border-bottom: 1px solid var(--border);
}

.section-title {
  font-family: var(--font-display);
  font-size: 1.25rem;
  font-weight: 800;
  margin-bottom: 1.5rem;
  text-transform: uppercase;
  letter-spacing: -0.02em;
}

.topic-item {
  display: flex;
  align-items: center;
  gap: 1rem;
  padding: 1rem 0;
  border-top: 1px solid var(--border);
  cursor: pointer;
  transition: opacity 150ms var(--ease-out), transform 150ms var(--ease-out);
}

.topics-list .topic-item:first-child { border-top: none; padding-top: 0; }

.topic-item:hover { opacity: 0.6; }

.topic-depth-indicator {
  width: 12px; height: 12px;
  flex-shrink: 0;
}

.topic-name {
  flex: 1;
  font-size: 1rem;
  font-weight: 500;
  color: var(--text-main);
}

/* Checkbox */
.custom-checkbox {
  position: relative;
  width: 20px; height: 20px;
  cursor: pointer;
}
.custom-checkbox input { position: absolute; opacity: 0; }

.checkmark {
  position: absolute;
  top: 0; left: 0;
  width: 20px; height: 20px;
  border: 2px solid var(--border-strong);
  transition: background-color 150ms var(--ease-out), border-color 150ms var(--ease-out);
}

.custom-checkbox input:checked ~ .checkmark {
  background-color: var(--text-main);
  border-color: var(--text-main);
}

.checkmark::after {
  content: ""; position: absolute; display: none;
  left: 5px; top: 1px;
  width: 4px; height: 10px;
  border: solid var(--bg-surface);
  border-width: 0 2px 2px 0;
  transform: rotate(45deg);
}

.custom-checkbox input:checked ~ .checkmark::after { display: block; }

.topic-item.completed .topic-name {
  text-decoration: line-through;
  color: var(--text-muted);
}

/* Modal */
.modal {
  display: none;
  position: fixed;
  inset: 0;
  background: rgba(244, 244, 235, 0.9);
  backdrop-filter: blur(8px);
  z-index: 1000;
  opacity: 0;
  transition: opacity 250ms var(--ease-out);
}

.modal.show { opacity: 1; }

.modal-content {
  background: var(--bg-surface);
  border: 2px solid var(--text-main);
  box-shadow: 16px 16px 0 var(--text-main);
  margin: 15vh auto;
  max-width: 600px;
  padding: 3rem;
  position: relative;
  transform: translateY(20px) scale(0.98);
  opacity: 0;
  transition: transform 300ms var(--ease-fluid), opacity 300ms var(--ease-out);
}

.modal.show .modal-content {
  transform: translateY(0) scale(1);
  opacity: 1;
}

#modal-title {
  font-family: var(--font-display);
  font-size: 2.75rem;
  font-weight: 800;
  line-height: 1.1;
  margin-bottom: 2rem;
  letter-spacing: -0.04em;
  padding-right: 2rem;
}

.close-modal {
  position: absolute;
  top: 1.5rem; right: 1.5rem;
  font-size: 2rem;
  cursor: pointer;
  line-height: 1;
  transition: transform 150ms var(--ease-out);
}
.close-modal:hover { transform: scale(1.1); }

.modal-meta { margin-bottom: 1.5rem; }

.modal-desc {
  font-size: 1.15rem;
  color: var(--text-muted);
  line-height: 1.6;
  margin-bottom: 3rem;
}

.modal-cb-wrapper {
  display: flex;
  align-items: center;
  gap: 1rem;
  font-family: var(--font-display);
  font-size: 1.25rem;
  font-weight: 800;
  text-transform: uppercase;
  cursor: pointer;
}

/* Toast */
.toast {
  position: fixed;
  bottom: 2rem; right: 2rem;
  background: var(--text-main);
  color: var(--bg-surface);
  font-family: var(--font-display);
  font-weight: 800;
  padding: 1rem 2rem;
  text-transform: uppercase;
  z-index: 2000;
  pointer-events: none;
  opacity: 0;
  transform: translateY(20px);
  transition: opacity 200ms var(--ease-out), transform 200ms var(--ease-out);
}
.toast.show { opacity: 1; transform: translateY(0); }

@keyframes fadeUp {
  from { opacity: 0; transform: translateY(20px); }
  to { opacity: 1; transform: translateY(0); }
}

@media (max-width: 768px) {
  .app-container { padding: 2rem 1rem; }
  .header-titles { margin-bottom: 2rem !important; }
  h1 { font-size: clamp(2.5rem, 12vw, 3.5rem); }
  
  .header-content { flex-direction: column !important; align-items: stretch !important; gap: 2rem !important; }
  .progress-container { max-width: 100% !important; }
  
  .controls-bar { flex-wrap: wrap; gap: 0.5rem; }
  .btn { flex: 1 1 100px; text-align: center; }
  
  .sections-grid { grid-template-columns: 1fr; }
  .section-card { padding: 1.5rem 1rem; border-right: none; }
  
  .stage-header { padding: 1.5rem 1rem; flex-wrap: wrap; }
  .stage-dot { width: 100%; margin-bottom: 0.5rem; font-size: 2.75rem; }
  .stage-title { font-size: 1.75rem; line-height: 1.1; margin-bottom: 0.5rem; }
  .stage-meta { flex-wrap: wrap; }
  
  .modal-content { margin: 10vh 1rem; padding: 1.5rem; box-shadow: 6px 6px 0 var(--text-main); }
  #modal-title { font-size: 2rem; margin-bottom: 1rem; padding-right: 0; }
  .modal-cb-wrapper { font-size: 1.1rem; }
}

/* Custom Scrollbar */
::-webkit-scrollbar {
  width: 10px;
  height: 10px;
}
::-webkit-scrollbar-track {
  background: var(--bg-main);
  border-left: 1px solid var(--border);
  border-top: 1px solid var(--border);
}
::-webkit-scrollbar-thumb {
  background: var(--border-strong);
}
::-webkit-scrollbar-thumb:hover {
  background: var(--accent);
}