@import url('https://fonts.googleapis.com/css2?family=Inter:wght@300;400;500;600;700&display=swap');

:root {
  --primary-color: #3b82f6;
  --primary-hover: #2563eb;
  --bg-color: #f8fafc;
  --surface-color: #ffffff;
  --text-main: #1e293b;
  --text-muted: #64748b;
  --border-color: #e2e8f0;
  --sidebar-width: 280px;
  --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.05);
  --shadow-md: 0 4px 6px -1px rgb(0 0 0 / 0.1), 0 2px 4px -2px rgb(0 0 0 / 0.1);
  --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.1), 0 4px 6px -4px rgb(0 0 0 / 0.1);
}

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

body {
  font-family: 'Inter', sans-serif;
  background-color: var(--bg-color);
  color: var(--text-main);
  line-height: 1.6;
  display: flex;
  scroll-behavior: smooth;
}

/* Sidebar */
.sidebar {
  width: var(--sidebar-width);
  height: 100vh;
  background-color: var(--surface-color);
  border-right: 1px solid var(--border-color);
  position: fixed;
  top: 0;
  left: 0;
  overflow-y: auto;
  padding: 2rem 0;
  z-index: 100;
  box-shadow: var(--shadow-sm);
}

.sidebar-header {
  padding: 0 2rem 2rem;
  border-bottom: 1px solid var(--border-color);
  margin-bottom: 1rem;
}

.sidebar-header h1 {
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--primary-color);
}

.sidebar-nav ul {
  list-style: none;
}

.sidebar-nav li a {
  display: block;
  padding: 0.75rem 2rem;
  color: var(--text-muted);
  text-decoration: none;
  font-weight: 500;
  transition: all 0.2s ease;
}

.sidebar-nav li a:hover,
.sidebar-nav li a.active {
  color: var(--primary-color);
  background-color: rgba(59, 130, 246, 0.05);
  border-right: 3px solid var(--primary-color);
}

/* Main Content */
.main-content {
  margin-left: var(--sidebar-width);
  flex: 1;
  padding: 3rem 4rem;
  max-width: 1200px;
}

section {
  margin-bottom: 5rem;
  padding-top: 2rem;
}

.section-title {
  font-size: 2.25rem;
  font-weight: 700;
  margin-bottom: 1rem;
  color: var(--text-main);
}

.section-desc {
  font-size: 1.125rem;
  color: var(--text-muted);
  margin-bottom: 2rem;
}

/* Steps */
.step-container {
  background: var(--surface-color);
  border-radius: 12px;
  padding: 2rem;
  margin-bottom: 2rem;
  box-shadow: var(--shadow-md);
  border: 1px solid var(--border-color);
  transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.step-container:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-lg);
}

.step-header {
  display: flex;
  align-items: center;
  margin-bottom: 1.5rem;
}

.step-number {
  background: var(--primary-color);
  color: white;
  width: 32px;
  height: 32px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 600;
  margin-right: 1rem;
}

.step-title {
  font-size: 1.25rem;
  font-weight: 600;
}

.step-content {
  display: flex;
  gap: 2rem;
  align-items: flex-start;
}

.step-text {
  flex: 1;
}

.step-text p {
  margin-bottom: 1rem;
}

.step-text ul {
  margin-left: 1.5rem;
  margin-bottom: 1rem;
  color: var(--text-muted);
}

.step-image {
  flex: 1;
  border-radius: 8px;
  overflow: hidden;
  border: 1px solid var(--border-color);
  background: #f1f5f9;
  display: flex;
  align-items: center;
  justify-content: center;
  min-height: 200px;
  cursor: pointer;
  transition: opacity 0.2s ease;
}

.step-image:hover {
  opacity: 0.9;
}

.step-image img {
  width: 100%;
  height: auto;
  display: block;
}

.placeholder-img {
  color: var(--text-muted);
  font-size: 0.875rem;
  font-weight: 500;
}

/* Responsive */
@media (max-width: 1024px) {
  .step-content {
    flex-direction: column;
  }
  .step-image {
    width: 100%;
  }
}

@media (max-width: 768px) {
  .sidebar {
    transform: translateX(-100%);
  }
  .main-content {
    margin-left: 0;
    padding: 2rem;
  }
}