/* ===== Lesson Page Styling ===== */

.lesson-container {
  max-width: 1200px;
  margin: 50px auto;
  padding: 0 20px;
}

/* ===== Lesson Header ===== */
.lesson-header {
  text-align: center;
  margin-bottom: 50px;
  padding: 40px 20px;
  background: linear-gradient(135deg, rgba(184, 104, 202, 0.1), rgba(91, 21, 96, 0.05));
  border-radius: 15px;
  border-left: 5px solid #20A8DC;
}

.lesson-header h1 {
  color: #0b63d4;
  font-size: 36px;
  margin: 0 0 15px 0;
}

.lesson-header h2 {
  color: #1e5ed6;
  font-size: 28px;
  margin: 0 0 10px 0;
}

.lesson-subtitle {
  color: #666;
  font-size: 14px;
  margin: 0;
}

/* ===== Main Lesson Section ===== */
.lesson-view-section,
.lesson-list-section,
.lesson-all-section {
  background: white;
  border-radius: 15px;
  padding: 30px;
  box-shadow: 0 5px 15px rgba(0, 0, 0, 0.1);
}

/* ===== Content Box ===== */
.lesson-content-box {
  background: linear-gradient(135deg, #ffffff 0%, #f8f9fa 100%);
  padding: 30px;
  border-radius: 12px;
  margin: 30px 0;
  border-left: 5px solid #20A8DC;
}

.lesson-content-box h2 {
  color: #0b63d4;
  margin-top: 0;
}

/* ===== File Section ===== */
.lesson-file-section {
  background: white;
  padding: 20px;
  border-radius: 10px;
  margin: 20px 0;
  border: 2px dashed #2b7cff;
}

.file-info {
  margin-bottom: 15px;
}

.file-info p {
  margin: 0;
  color: #333;
  font-size: 14px;
}

.no-file {
  text-align: center;
  color: #999;
  padding: 20px;
  font-size: 14px;
}

/* ===== Download Button ===== */
.btn-download {
  display: inline-block;
  padding: 12px 30px;
  background: linear-gradient(135deg, #51cf66, #69db7c);
  color: white;
  text-decoration: none;
  border-radius: 8px;
  font-weight: bold;
  transition: all 0.3s;
  margin-top: 10px;
}

.btn-download:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 20px rgba(81, 207, 102, 0.4);
  background: linear-gradient(135deg, #40c057, #51cf66);
}

/* ===== Sheets Container ===== */
.sheets-container {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: 20px;
  margin: 30px 0;
}

.sheet-card {
  background: linear-gradient(135deg, #ffffff 0%, #f8f9fa 100%);
  border: 2px solid #e0e0e0;
  border-radius: 12px;
  padding: 20px;
  display: flex;
  align-items: center;
  gap: 15px;
  transition: all 0.3s;
  cursor: pointer;
}

.sheet-card:hover {
  border-color: #2b7cff;
  box-shadow: 0 8px 25px rgba(43,124,255,0.2);
  transform: translateY(-5px);
}

.sheet-icon {
  font-size: 32px;
  min-width: 50px;
  text-align: center;
}

.sheet-content {
  flex: 1;
}

.sheet-content h3 {
  color: #0b63d4;
  margin: 0 0 5px 0;
  font-size: 16px;
}

.sheet-content p {
  color: #999;
  margin: 0;
  font-size: 13px;
}

.btn-view {
  background: linear-gradient(135deg, #63C1E5, #20A8DC);
  color: white;
  padding: 8px 20px;
  text-decoration: none;
  border-radius: 6px;
  white-space: nowrap;
  font-size: 13px;
  font-weight: bold;
  transition: all 0.3s;
  display: inline-block;
}

.btn-view:hover {
  background: linear-gradient(135deg, #1e5ed6, #1960c8);
  box-shadow: 0 5px 12px rgba(43,124,255,0.3);
}

/* ===== No Sheets State ===== */
.no-sheets {
  text-align: center;
  padding: 40px 20px;
  color: #999;
  background: #f9f9f9;
  border-radius: 10px;
}

/* ===== Lessons Grid ===== */
.lessons-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(250px, 1fr));
  gap: 25px;
  margin: 30px 0;
}

.lesson-card {
  background: white;
  border: 2px solid #e0e0e0;
  border-radius: 12px;
  overflow: hidden;
  transition: all 0.3s;
  display: flex;
  flex-direction: column;
  box-shadow: 0 3px 10px rgba(0, 0, 0, 0.08);
}

.lesson-card:hover {
  border-color: #3764c7;
  box-shadow: 0 12px 30px rgba(184, 104, 202, 0.2);
  transform: translateY(-8px);
}

.lesson-card-header {
  background: linear-gradient(135deg, #6397eb, #447be2);
  color: white;
  padding: 20px;
  text-align: center;
}

.lesson-card-header h3 {
  margin: 0;
  font-size: 18px;
}

.lesson-card-body {
  padding: 20px;
  flex: 1;
}

.lesson-card-body h4 {
  color: #0b63d4;
  margin: 0 0 10px 0;
  font-size: 16px;
}

.lesson-card-body p {
  color: #999;
  margin: 0 0 10px 0;
  font-size: 13px;
  line-height: 1.4;
}

.lesson-stats {
  background: rgba(43,124,255,0.06);
  padding: 10px;
  border-radius: 6px;
  color: #0b63d4;
  font-size: 12px;
  font-weight: bold;
  margin: 0 !important;
}

.btn-enter {
  display: block;
  background: linear-gradient(135deg, #73a5f5, #548cf5);
  color: white !important;
  padding: 12px 20px;
  text-decoration: none !important;
  text-align: center;
  border-radius: 6px;
  margin: 15px;
  font-weight: bold;
  transition: all 0.3s;
}

.btn-enter:hover {
  background: linear-gradient(135deg, #1e5ed6, #1960c8);
  box-shadow: 0 5px 12px rgba(43,124,255,0.3);
}

/* ===== No Lessons State ===== */
.no-lessons {
  text-align: center;
  padding: 60px 20px;
  color: #999;
  grid-column: 1 / -1;
}

/* ===== Navigation ===== */
.lesson-navigation {
  margin-top: 40px;
  display: flex;
  gap: 15px;
  justify-content: center;
  flex-wrap: wrap;
}

.btn {
  padding: 12px 25px;
  border-radius: 8px;
  text-decoration: none;
  transition: all 0.3s;
  font-weight: bold;
  display: inline-block;
  font-size: 14px;
}

.btn-back {
  background: linear-gradient(135deg, #5ba0ce, #3583b7);
  color: white;
}

.btn-back:hover {
  background: linear-gradient(135deg, #427496, #286690);
  transform: translateY(-2px);
  box-shadow: 0 5px 12px rgba(50, 96, 182, 0.3);
}

/* ===== Responsive Design ===== */
@media (max-width: 1024px) {
  .lesson-container {
    margin: 30px auto;
  }

  .lesson-header h1 {
    font-size: 28px;
  }

  .lesson-header h2 {
    font-size: 22px;
  }

  .lessons-grid {
    grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
  }

  .sheets-container {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 768px) {
  .lesson-container {
    margin: 20px auto;
    padding: 0 10px;
  }

  .lesson-header {
    padding: 30px 15px;
    margin-bottom: 30px;
  }

  .lesson-header h1 {
    font-size: 22px;
  }

  .lesson-header h2 {
    font-size: 18px;
  }

  .lesson-content-box {
    padding: 20px;
    margin: 20px 0;
  }

  .lessons-grid {
    grid-template-columns: 1fr;
  }

  .sheets-container {
    grid-template-columns: 1fr;
  }

  .sheet-card {
    gap: 10px;
  }

  .sheet-icon {
    font-size: 28px;
  }

  .lesson-navigation {
    flex-direction: column;
  }

  .btn {
    width: 100%;
    text-align: center;
  }
}

@media (max-width: 480px) {
  .lesson-container {
    margin: 15px auto;
  }

  .lesson-header {
    padding: 20px 10px;
    margin-bottom: 20px;
  }

  .lesson-header h1 {
    font-size: 18px;
  }

  .lesson-header h2 {
    font-size: 16px;
  }

  .lesson-subtitle {
    font-size: 12px;
  }

  .lesson-card-header h3 {
    font-size: 14px;
  }

  .lesson-card-body h4 {
    font-size: 14px;
  }

  .file-info p {
    font-size: 12px;
    word-break: break-all;
  }
}