/* 1. Reset định dạng cơ bản */
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
  font-family: 'Inter', sans-serif;
}

body {
  background-color: #f8fafc;
}

/* 2. Khung Sidebar Cố Định */
.sidebar {
  width: 260px;
  height: 100vh;
  background: white;
  display: flex;
  flex-direction: column;
  border-right: 1px solid #e2e8f0;
  position: fixed;
  left: 0;
  top: 0;
  padding: 20px 0;
  z-index: 100;
}

.logo-section {
  display: flex;
  align-items: center;
  padding: 0 20px 30px;
}

.logo-icon {
  width: 32px;
  height: 32px;
  background: #7c3aed;
  color: white;
  border-radius: 8px;
  display: flex;
  justify-content: center;
  align-items: center;
  margin-right: 12px;
}

.brand-name {
  display: block;
  font-weight: 700;
  font-size: 18px;
  color: #1e293b;
}

.sub-text {
  font-size: 12px;
  color: #64748b;
}

.menu {
  flex-grow: 1;
}

.menu-item {
  display: flex;
  align-items: center;
  padding: 12px 20px;
  margin: 4px 16px;
  border-radius: 10px;
  color: #475569;
  text-decoration: none;
  font-weight: 500;
  transition: 0.2s;
}

.menu-item i {
  margin-right: 12px;
  width: 20px;
  text-align: center;
}

.menu-item.active {
  background: linear-gradient(135deg, #7c3aed, #a855f7);
  color: white;
}

.menu-item:hover:not(.active) {
  background-color: #f1f5f9;
}

.today-stats {
  background-color: #f0fdf4;
  margin: 20px;
  padding: 16px;
  border-radius: 12px;
}

.stats-title {
  font-size: 13px;
  color: #15803d;
  font-weight: 600;
  margin-bottom: 12px;
}

.stats-row {
  display: flex;
  justify-content: space-between;
  font-size: 13px;
  margin-bottom: 8px;
  color: #334155;
}

.count {
  font-weight: 700;
}

.count.green {
  color: #22c55e;
}

.count.red {
  color: #ef4444;
}

/* 3. Layout Nội Dung Chính - ĐÃ SỬA ĐỂ CĂN GIỮA */
.main-content,
.pomodoro-container {
  margin-left: 260px;
  width: calc(100% - 260px);
  padding: 40px;
  background-color: #f8faff;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  align-items: center; /* Thêm dòng này để căn giữa mọi thứ trong trang Thống kê/Nhạc */
}

/* Ép các khối con trong main-content không giãn quá rộng */
.main-content > * {
    width: 100%;
    max-width: 1000px; /* Độ rộng tối đa để cân đối giữa màn hình */
}

/* Cấu trúc riêng cho trang Nhiệm vụ */
.main-content h1 {
  font-size: 24px;
  margin-bottom: 30px;
  color: #1a1a1a;
  text-align: left; /* Tiêu đề vẫn để bên trái cho đẹp */
}

.stats-container {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 20px;
  margin-bottom: 30px;
}

.stat-card {
  padding: 20px;
  border-radius: 12px;
  height: 100px;
}

.stat-card p {
  font-size: 14px;
  margin-bottom: 8px;
  color: #666;
}

.stat-number {
  font-size: 28px;
  font-weight: bold;
}

.stat-card.blue {
  background-color: #f0f7ff;
}

.stat-card.green {
  background-color: #f0fdf4;
}

.stat-card.orange {
  background-color: #fffaf0;
}

.add-task-bar {
  display: flex;
  gap: 10px;
  background: white;
  padding: 10px;
  border-radius: 10px;
  border: 1px solid #e2e8f0;
  margin-bottom: 20px;
}

.task-input {
  flex-grow: 1;
  border: none;
  outline: none;
  padding: 10px;
  font-size: 15px;
}

.priority-select {
  border: 1px solid #e2e8f0;
  border-radius: 8px;
  padding: 0 15px;
  background: #fff;
  cursor: pointer;
}

.add-btn {
  background-color: #2563eb;
  color: white;
  border: none;
  padding: 10px 25px;
  border-radius: 8px;
  font-weight: 600;
  cursor: pointer;
}

.filter-group {
  display: flex;
  gap: 10px;
  margin-bottom: 50px;
}

.filter-btn {
  padding: 8px 18px;
  border-radius: 8px;
  border: none;
  background: #e2e8f0;
  color: #475569;
  font-weight: 500;
  cursor: pointer;
}

.filter-btn.active {
  background-color: #2563eb;
  color: white;
}

.empty-state {
  text-align: center;
  color: #94a3b8;
  margin-top: 100px;
  font-size: 15px;
}

/* 4. Cấu trúc riêng cho trang Pomodoro */
.pomodoro-container {
  align-items: center;
  padding: 60px 20px;
}

.pomo-header {
  text-align: center;
  margin-bottom: 30px;
}

.pomo-header h1 {
  font-size: 28px;
  margin-bottom: 5px;
}

.pomo-count {
  color: #64748b;
  font-size: 14px;
}

.mode-switch {
  display: flex;
  justify-content: center;
  gap: 15px;
  margin-bottom: 40px;
}

.mode-btn {
  padding: 10px 25px;
  border-radius: 12px;
  border: none;
  font-weight: 600;
  cursor: pointer;
  display: flex;
  align-items: center;
  gap: 8px;
  transition: 0.3s;
}

.mode-btn.red {
  background-color: #ef4444;
  color: white;
}

.mode-btn.gray {
  background-color: #e2e8f0;
  color: #475569;
}

.timer-display {
  background: white;
  padding: 40px 80px;
  border-radius: 24px;
  box-shadow: 0 10px 30px rgba(0, 0, 0, 0.05);
  margin-bottom: 40px;
  display: flex;
  justify-content: center;
}

.circle-outer {
  width: 280px;
  height: 280px;
  border: 15px solid #f1f5f9;
  border-radius: 50%;
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
}

.minutes {
  font-size: 60px;
  font-weight: 800;
  color: #1e293b;
  display: block;
}

.label {
  color: #64748b;
  font-size: 16px;
  margin-top: -5px;
  text-align: center;
}

.controls {
  display: flex;
  justify-content: center;
  gap: 20px;
  margin-bottom: 50px;
}

.start-btn {
  background-color: #00ca4e;
  color: white;
  padding: 15px 40px;
  border-radius: 12px;
  border: none;
  font-size: 18px;
  font-weight: bold;
  cursor: pointer;
  box-shadow: 0 4px 15px rgba(0, 202, 78, 0.3);
}

.reset-btn {
  background-color: #64748b;
  color: white;
  padding: 15px 30px;
  border-radius: 12px;
  border: none;
  font-size: 18px;
  cursor: pointer;
}

.pomo-info {
  width: 100%;
  max-width: 500px;
  background-color: #eff6ff;
  padding: 25px;
  border-radius: 12px;
  color: #1e40af;
}

.pomo-info h3 {
  font-size: 16px;
  margin-bottom: 10px;
}

.pomo-info ul {
  padding-left: 20px;
  font-size: 14px;
  line-height: 1.8;
}


/* --- TRANG THỐNG KÊ (ĐÃ GOM LẠI CHUẨN) --- */
.stats-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 20px;
    margin-bottom: 40px;
}

.stat-box {
    padding: 30px;
    border-radius: 16px;
    display: flex;
    flex-direction: column;
    gap: 12px;
    transition: transform 0.2s;
}

.stat-box:hover {
    transform: translateY(-5px);
}

.stat-box.blue { background-color: #ebf5ff; color: #3b82f6; }
.stat-box.red { background-color: #fff1f2; color: #f43f5e; }
.stat-box.green { background-color: #f0fdf4; color: #22c55e; }
.stat-box.purple { background-color: #faf5ff; color: #a855f7; }

.stat-box i { font-size: 24px; }
.stat-box .value { font-size: 32px; font-weight: 800; }
.stat-box .label { font-size: 14px; font-weight: 500; opacity: 0.8; }

.achievement-container {
    background-color: #fffbeb;
    padding: 30px;
    border-radius: 20px;
    border: 1px solid #fef3c7;
}

.achievement-header {
    font-size: 20px;
    font-weight: 700;
    color: #92400e;
    margin-bottom: 25px;
    display: flex;
    align-items: center;
    gap: 12px;
}

.achievement-item {
    background: white;
    margin-bottom: 15px;
    padding: 20px 25px;
    border-radius: 12px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    box-shadow: 0 2px 4px rgba(0,0,0,0.02);
}

.achievement-info {
    display: flex;
    align-items: center;
    gap: 15px;
}

.achievement-info .icon { font-size: 20px; }
.achievement-info .name { font-weight: 600; color: #1e293b; font-size: 16px; }
.achievement-item .requirement { font-size: 14px; color: #64748b; }

/* --- TRANG NHẠC (MUSIC PAGE) --- */


.player-container {
    background: white;
    width: 100%;
    max-width: 500px;
    padding: 30px;
    border-radius: 24px;
    box-shadow: 0 10px 30px rgba(0,0,0,0.05);
    margin-bottom: 30px;
}

.player-header {
    font-weight: 700;
    color: #7c3aed;
    margin-bottom: 20px;
    display: flex;
    align-items: center;
    gap: 10px;
}

.now-playing-card {
    text-align: center;
    margin-bottom: 30px;
}

.album-art {
    width: 120px;
    height: 120px;
    background: linear-gradient(135deg, #a78bfa, #7c3aed);
    border-radius: 50%;
    margin: 0 auto 20px;
    display: flex;
    justify-content: center;
    align-items: center;
    color: white;
    font-size: 40px;
}

.song-info h3 { font-size: 18px; margin-bottom: 5px; }
.song-info p { color: #64748b; font-size: 14px; margin-bottom: 10px; }
.song-info .tag {
    background: #f1f5f9;
    padding: 2px 12px;
    border-radius: 20px;
    font-size: 12px;
    color: #64748b;
}

.player-controls {
    display: flex;
    justify-content: center;
    gap: 20px;
    margin: 20px 0;
}

.play-btn {
    width: 50px;
    height: 50px;
    background: #7c3aed;
    color: white;
    border: none;
    border-radius: 50%;
    cursor: pointer;
}

.next-btn {
    width: 50px;
    height: 50px;
    background: #f1f5f9;
    color: #64748b;
    border: none;
    border-radius: 50%;
    cursor: pointer;
}

.volume-slider {
    display: flex;
    align-items: center;
    gap: 10px;
    color: #64748b;
}

.volume-slider input { flex-grow: 1; accent-color: #7c3aed; }

.playlist-title { font-weight: 600; margin-bottom: 15px; font-size: 14px; color: #475569; }
.playlist-item {
    padding: 12px 15px;
    border-radius: 12px;
    cursor: pointer;
    transition: 0.2s;
    margin-bottom: 8px;
}

.playlist-item.active { background-color: #f5f3ff; border-left: 4px solid #7c3aed; }
.playlist-item:hover:not(.active) { background-color: #f8fafc; }
.item-text strong { display: block; font-size: 14px; }
.item-text span { font-size: 12px; color: #94a3b8; }

.music-tips {
    width: 100%;
    max-width: 500px;
    background-color: white;
    padding: 25px;
    border-radius: 20px;
}

.music-tips h3 { font-size: 16px; margin-bottom: 15px; }
.music-tips ul { list-style: none; }
.music-tips li { font-size: 14px; color: #475569; margin-bottom: 12px; display: flex; align-items: center; gap: 10px; }
.music-tips i { color: #3b82f6; width: 20px; }


/* --- INTRO PAGE STYLES --- */
.intro-page {
    background-color: #f8faff;
    color: #1e293b;
}

.intro-header {
    display: flex;
    justify-content: space-between;
    padding: 20px 10%;
    align-items: center;
    background: white;
}

.start-nav-btn {
    background: linear-gradient(135deg, #6366f1, #a855f7);
    color: white;
    padding: 8px 25px;
    border-radius: 8px;
    text-decoration: none;
    font-weight: 600;
}

.start-nav-bt {
    background: linear-gradient(135deg, #6366f1, #a855f7);
    color: white;
    padding: 8px 25px;
    border-radius: 8px;
    text-decoration: none;
    font-weight: 600;
}
.hero {
    text-align: center;
    padding: 80px 10%;
}

.hero h1 {
    font-size: 48px;
    color: #6366f1;
    margin-bottom: 20px;
}

.feature-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 25px;
    padding: 40px 10%;
}

.feature-card {
    background: white;
    padding: 30px;
    border-radius: 20px;
    text-align: center;
    box-shadow: 0 10px 25px rgba(0,0,0,0.05);
}

.f-icon {
    width: 50px;
    height: 50px;
    border-radius: 12px;
    display: flex;
    justify-content: center;
    align-items: center;
    margin: 0 auto 20px;
    color: white;
    font-size: 20px;
}

.f-icon.blue { background: #3b82f6; }
.f-icon.red { background: #ef4444; }
.f-icon.purple { background: #a855f7; }
.f-icon.green { background: #22c55e; }

/* CTA Card */
.cta-section {
    padding: 80px 10%;
}

.cta-card {
    background: linear-gradient(135deg, #3b82f6, #a855f7);
    padding: 60px;
    border-radius: 24px;
    text-align: center;
    color: white;
}

.cta-btn {
    display: inline-block;
    margin-top: 30px;
    background: white;
    color: #6366f1;
    padding: 15px 40px;
    border-radius: 12px;
    text-decoration: none;
    font-weight: 700;
}



.how-to-use {
    padding: 60px 10%;
    text-align: center;
    background-color: #f8faff;
}

.how-to-use h2 {
    margin-bottom: 40px;
    font-size: 28px;
}

.step-container {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 25px; /* Khoảng cách giữa các bước */
}

.step-item {
    display: flex;
    align-items: center;
    width: 100%;
    max-width: 800px;
    gap: 20px;
}

.step-number {
    width: 45px;
    height: 45px;
    background: linear-gradient(135deg, #6366f1, #a855f7);
    color: white;
    border-radius: 50%;
    display: flex;
    justify-content: center;
    align-items: center;
    font-weight: bold;
    flex-shrink: 0; /* Không cho vòng tròn bị bẹp */
    box-shadow: 0 4px 10px rgba(99, 102, 241, 0.3);
}

.step-card {
    background: white;
    padding: 20px 30px;
    border-radius: 15px;
    flex-grow: 1;
    text-align: left;
    box-shadow: 0 10px 25px rgba(0, 0, 0, 0.05); /* Đổ bóng nhẹ */
    transition: 0.3s;
}

.step-card:hover {
    transform: translateX(10px); /* Hiệu ứng nhích sang phải khi di chuột */
}

.step-title {
    font-weight: 700;
    font-size: 18px;
    margin-bottom: 8px;
    display: flex;
    align-items: center;
    gap: 10px;
    color: #1e293b;
}

.step-card p {
    color: #64748b;
    font-size: 14px;
}




.logo, .logo-section {
  display: flex;
  align-items: center; /* Quan trọng: giúp icon và chữ thẳng hàng */
  gap: 12px;
  padding: 0 20px 30px;
}

.logo-icon {
  width: 32px;
  height: 32px;
  background: #7c3aed;
  color: white;
  border-radius: 8px;
  display: flex;
  justify-content: center;
  align-items: center;
  flex-shrink: 0;
}

.brand-name, .logo span {
  font-weight: 700;
  font-size: 18px;
  color: #1e293b;
}

/* 3. Layout Nội Dung Chính (Dành cho trang Nhiệm vụ, Pomodoro, Thống kê, Nhạc) */
.main-content,
.pomodoro-container {
  margin-left: 260px; /* Chừa khoảng trống cho Sidebar */
  width: calc(100% - 260px);
  padding: 40px;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  align-items: center; /* ÉP TẤT CẢ NỘI DUNG VÀO GIỮA CHIỀU NGANG */
  background-color: #f8faff;
}

/* Giới hạn độ rộng nội dung để cân đối */
.main-content > *, 
.pomodoro-container > * {
  width: 100%;
  max-width: 1000px; 
}

/* 4. TRANG GIỚI THIỆU (Intro.html - Đã sửa lỗi căn giữa) */
.intro-page { background-color: #f8faff; }

.intro-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 20px 10%;
  background: white;
  width: 100%;
  box-shadow: 0 2px 10px rgba(0,0,0,0.02);
}

.intro-header .logo { padding: 0; } /* Bỏ padding dư thừa ở header intro */

.start-nav-btn {
  background: linear-gradient(135deg, #6366f1, #a855f7);
  color: white;
  padding: 10px 25px;
  border-radius: 8px;
  text-decoration: none;
  font-weight: 600;
}

.hero {
  text-align: center;
  padding: 80px 10%;
  width: 100%;
}

.hero h1 { font-size: 48px; color: #6366f1; margin-bottom: 20px; }

/* SỬA LỖI: Tính năng chính về giữa */
.features {
  padding: 80px 10%;
  width: 100%;
  display: flex;
  flex-direction: column;
  align-items: center;
}

.features h2 { margin-bottom: 50px; font-size: 32px; font-weight: 700; }

.feature-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: 30px;
  width: 100%;
  max-width: 1200px;
  margin: 0 auto; /* Căn giữa khối Grid */
}

.feature-card {
  background: white;
  padding: 40px 30px;
  border-radius: 20px;
  text-align: center;
  box-shadow: 0 10px 30px rgba(0,0,0,0.05);
  transition: transform 0.3s;
}

.feature-card:hover { transform: translateY(-10px); }

/* SỬA LỖI: Cách sử dụng & Pomodoro Intro về giữa */
.how-to-use {
  padding: 60px 10%;
  display: flex;
  flex-direction: column;
  align-items: center;
  width: 100%;
}

.step-container {
  display: flex;
  flex-direction: column;
  gap: 25px;
  width: 100%;
  max-width: 800px;
}

.step-item {
  display: flex;
  align-items: center;
  gap: 20px;
  width: 100%;
}

.step-number {
  width: 45px;
  height: 45px;
  background: linear-gradient(135deg, #6366f1, #a855f7);
  color: white;
  border-radius: 50%;
  display: flex;
  justify-content: center;
  align-items: center;
  font-weight: bold;
  flex-shrink: 0;
}

.step-card {
  background: white;
  padding: 25px 30px;
  border-radius: 15px;
  flex-grow: 1;
  text-align: left;
  box-shadow: 0 10px 25px rgba(0,0,0,0.05);
}

.pomo-intro-card {
  background: white;
  padding: 35px;
  border-radius: 20px;
  box-shadow: 0 10px 30px rgba(0,0,0,0.03);
  margin: 40px auto; /* Căn giữa khối này */
  width: 90%;
  max-width: 900px;
}

/* 5. Các thành phần bổ trợ (Menu, Stats, Player, v.v.) */
.menu-item {
  display: flex;
  align-items: center;
  padding: 12px 20px;
  margin: 4px 16px;
  border-radius: 10px;
  color: #475569;
  text-decoration: none;
  font-weight: 500;
  transition: 0.2s;
}

.menu-item.active { background: linear-gradient(135deg, #7c3aed, #a855f7); color: white; }

.pomo-standard { background-color: #f5f3ff; padding: 25px; border-radius: 15px; margin-bottom: 25px; }
.dot { width: 8px; height: 8px; border-radius: 50%; display: inline-block; margin-right: 8px; }
.dot.blue { background-color: #3b82f6; }
.dot.green { background-color: #22c55e; }
.dot.purple { background-color: #a855f7; }

.cta-section { padding: 80px 10%; display: flex; justify-content: center; }
.cta-card {
  background: linear-gradient(135deg, #3b82f6, #a855f7);
  padding: 60px;
  border-radius: 24px;
  text-align: center;
  color: white;
  width: 100%;
  max-width: 900px;
}

.cta-btn {
  display: inline-block;
  margin-top: 30px;
  background: white;
  color: #6366f1;
  padding: 15px 40px;
  border-radius: 12px;
  text-decoration: none;
  font-weight: 700;
}


/* 1. Khung Header hồ sơ lớn cao cấp - Căn giữa bằng Flexbox */
.lab-profile-header {
  text-align: center;
  margin-bottom: 45px;
  padding: 35px 20px;
  background: #ffffff;
  border-radius: 20px;
  box-shadow: 0 10px 25px -5px rgba(124, 58, 237, 0.08), 0 8px 16px -6px rgba(0, 0, 0, 0.02);
  border: 1px solid #e2e8f0;
  position: relative;
  overflow: hidden;
  
  display: flex;
  flex-direction: column;
  align-items: center; /* Đẩy tên và các tag thông tin thẳng hàng ở chính giữa */
}

/* Đường sọc màu trang trí trên nóc hộp hồ sơ */
.lab-profile-header::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 5px;
  background: linear-gradient(90deg, #7c3aed, #a855f7, #ec4899);
}

/* Tên sinh viên hiệu ứng chữ Gradient chuyển màu nổi bật */
.lab-profile-header .student-name {
  font-family: 'Inter', sans-serif;
  font-size: 36px;
  font-weight: 900;
  letter-spacing: -1.5px;
  margin-bottom: 15px;
  
  background: linear-gradient(135deg, #4f46e5 0%, #7c3aed 40%, #ec4899 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  filter: drop-shadow(0 2px 8px rgba(124, 58, 237, 0.15));
}

/* Cụm chứa MSSV & Lịch học - Canh đều vào giữa hàng ngang */
.student-info-group {
  display: flex;
  justify-content: center; /* Căn giữa các mục con */
  align-items: center;
  gap: 30px;
  flex-wrap: wrap;
  margin-top: 10px;
  width: 100%;
}

.lab-profile-header .student-info {
  font-family: 'Inter', sans-serif;
  font-size: 15px;
  font-weight: 600;
  color: #475569;
  display: flex;
  align-items: center;
  gap: 8px;
}

.lab-profile-header .student-info i {
  color: #7c3aed;
  font-size: 16px;
}

/* Khung Highlight thông tin dạng nhãn Tag chuyên nghiệp */
.lab-profile-header .highlight-text {
  background: #f5f3ff;
  color: #6d28d9;
  padding: 4px 12px;
  border-radius: 8px;
  font-weight: 700;
  font-size: 14px;
  border: 1px solid #ddd6fe;
}

/* 2. Khối bao bọc phần danh sách bài tập - Căn giữa tiêu đề */
.lab-section {
  display: flex;
  flex-direction: column;
  align-items: center; /* Buộc tiêu đề section đứng ở giữa */
  width: 100%;
}

/* Tiêu đề mục "DANH SÁCH BÀI TẬP LAB" */
.lab-section-title {
  font-family: 'Inter', sans-serif;
  font-size: 20px;
  font-weight: 800;
  color: #0f172a;
  margin-bottom: 35px;
  text-transform: uppercase;
  letter-spacing: 1px;
  position: relative;
  display: inline-block;
  text-align: center;
}

/* Thanh nhấn trang trí nằm ngay TRỌNG TÂM dưới tiêu đề */
.lab-section-title::after {
  content: '';
  position: absolute;
  bottom: -8px;
  left: 50%;
  transform: translateX(-50%); /* Căn chuẩn 50% từ tâm chữ ra */
  width: 55px;
  height: 4px;
  background: linear-gradient(90deg, #7c3aed, #ec4899);
  border-radius: 10px;
}

/* 3. Lưới hiển thị các Card bài tập (Giữ nguyên tỉ lệ co giãn lưới rộng rãi bên phải) */
.lab-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 25px;
  width: 100%;
  padding-bottom: 60px;
}

/* Khung thẻ bài tập lẻ */
.lab-card {
  background: white;
  padding: 25px 20px;
  border-radius: 16px;
  box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.05), 0 2px 4px -1px rgba(0, 0, 0, 0.03);
  border: 1px solid #e2e8f0;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  gap: 15px;
  transition: transform 0.2s, box-shadow 0.2s;
}

.lab-card:hover {
  transform: translateY(-4px);
  box-shadow: 0 10px 15px -3px rgba(0, 0, 0, 0.05);
}

.lab-card h3 {
  font-size: 18px;
  color: #1e293b;
  font-weight: 700;
  text-align: center;
}

.lab-btn-group {
  display: flex;
  flex-direction: column;
  gap: 8px;
}

/* Nút liên kết xem bài tập lab */
.lab-btn {
  display: block;
  background: #f1f5f9;
  color: #475569;
  padding: 10px;
  text-align: center;
  text-decoration: none;
  border-radius: 8px;
  font-weight: 600;
  font-size: 14px;
  transition: all 0.2s;
}

.lab-btn:hover {
  background: linear-gradient(135deg, #7c3aed, #a855f7);
  color: white;
}