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

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  background: #ffffff;
  color: #333333;
}

/* Header */
.header {
  height: 56px;
  background: #1a1a2e;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 24px;
  color: white;
  font-weight: bold;
  font-size: 16px;
  letter-spacing: 1px;
}

.header a {
  color: rgba(255,255,255,0.7);
  font-size: 13px;
  text-decoration: none;
}

.header a:hover {
  color: white;
}

/* Layout */
.layout {
  display: flex;
  min-height: calc(100vh - 56px);
}

/* Sidebar */
.sidebar {
  width: 220px;
  background: #f7f7f7;
  border-right: 1px solid #e8e8e8;
  padding: 16px 0;
  flex-shrink: 0;
}

.section-label {
  display: block;
  padding: 12px 24px 4px;
  font-size: 11px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 1px;
  color: #999;
}

.sidebar-course-label {
  display: block;
  padding: 20px 24px 4px;
  font-size: 11px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 1px;
  color: #999;
  border-top: 1px solid #e8e8e8;
  margin-top: 8px;
}
.sidebar a {
  display: block;
  padding: 10px 16px;
  color: #444;
  text-decoration: none;
  font-size: 14px;
  border-radius: 4px;
  margin: 0 8px;
}

.sidebar a:hover { background: #efefef; }
.sidebar a.active { font-weight: 600; color: #1a1a2e; background: #e8e8e8; }

/* Sidebar lesson with circle */
.sidebar-lesson {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 10px 16px;
  color: #444;
  text-decoration: none;
  font-size: 14px;
  border-radius: 4px;
  margin: 0 8px;
}

.sidebar-lesson:hover { background: #f0f0f0; }

.sidebar-lesson.active {
  background: #e8e8e8;
  font-weight: 600;
  color: #1a1a2e;
}

.lesson-circle {
  width: 18px;
  height: 18px;
  border-radius: 50%;
  border: 2px solid #ccc;
  flex-shrink: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 11px;
}

.lesson-circle.done {
  background: #2ecc71;
  border-color: #2ecc71;
  color: white;
}

/* Content */
.content {
  flex: 1;
  padding: 32px 40px;
}

.content p {
  margin-bottom: 16px;
  line-height: 1.7;
}

.content h1 {
  font-size: 28px;
  font-weight: 700;
  margin-bottom: 16px;
  margin-top: 40px;
}

.content h2 {
  font-size: 22px;
  font-weight: 700;
  margin-top: 40px;
  margin-bottom: 16px;
}

.content h3 {
  font-size: 17px;
  font-weight: 700;
  margin-top: 28px;
  margin-bottom: 8px;
  color: #307cff;
}


.content ul {
  padding-left: 24px;
  margin-bottom: 16px;
  margin-top:0;
}

.content li {
  margin-bottom: 8px;
  line-height: 1.7;
}

/* Typography */
h1 { font-size: 26px; font-weight: 600; margin-bottom: 24px; }
h2 { font-size: 18px; font-weight: 600; margin-bottom: 16px; margin-top: 32px; }

/* Tables */
table {
  width: 100%;
  border-collapse: collapse;
  font-size: 14px;
}

th {
  text-align: left;
  padding: 10px 16px;
  border-bottom: 2px solid #e8e8e8;
  color: #888;
  font-weight: 500;
  font-size: 12px;
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

td {
  padding: 14px 16px;
  border-bottom: 1px solid #f2f2f2;
  font-size: 14px;
}

tr:hover td { background: #fafafa; }

/* Links */
a { color: #1a1a2e; }
a:hover { text-decoration: underline; }

/* Buttons */
.btn {
  display: inline-block;
  padding: 8px 18px;
  background: #1a1a2e;
  color: white;
  border: none;
  border-radius: 4px;
  font-size: 13px;
  font-weight: 500;
  cursor: pointer;
  text-decoration: none;
}

.btn:hover { background: #2d2d4e; color: white; text-decoration: none; }

.btn-outline {
  background: transparent;
  border: 1px solid #1a1a2e;
  color: #1a1a2e;
}

.btn-outline:hover { background: #1a1a2e; color: white; }

/* Login form */
.login-form p {
  margin-bottom: 16px;
}

.login-form label {
  display: block;
  font-size: 13px;
  font-weight: 500;
  margin-bottom: 6px;
  color: #555;
}

.login-form input {
  display: block;
  width: 100%;
  padding: 10px 14px;
  font-size: 14px;
  border: 1px solid #ddd;
  border-radius: 4px;
  outline: none;
}

.login-form input:focus {
  border-color: #1a1a2e;
}

.logout-btn {
  background: #2980b9;
  border: none;
  color: white;
  font-size: 13px;
  font-weight: 500;
  padding: 7px 16px;
  border-radius: 4px;
  cursor: pointer;
}

.logout-btn:hover {
  background: #2471a3;
}

.progress-bar-wrap {
  width: 100%;
  background: #e8e8e8;
  border-radius: 4px;
  height: 8px;
  margin-bottom: 8px;
}

.progress-bar-fill {
  height: 8px;
  background: #2ecc71;
  border-radius: 4px;
  transition: width 0.3s ease;
}

.progress-label {
  font-size: 13px;
  color: #888;
  margin-bottom: 24px;
}

.btn-orange {
  background: #e67e22;
  color: white;
  border: none;
}

.btn-orange:hover {
  background: #ca6f1e;
  color: white;
}

select {
  padding: 8px 12px;
  border: 1px solid #ddd;
  border-radius: 4px;
  font-size: 14px;
  outline: none;
}

.btn-x {
  background: #cc3333;
  color: white;
  border: none;
  border-radius: 4px;
  padding: 4px 8px;
  font-size: 12px;
  cursor: pointer;
}

.btn-x:hover {
  background: #aa2222;
}

.sidebar-lesson {
  display: flex !important;
  align-items: center;
  gap: 10px;
}