html {
  margin: 0;
  padding: 0;
}
body {
  font-family: "Mona Sans", sans-serif;
  margin: 0;
  padding: 0;
  min-height: 100vh;
  min-width: 1250px;
  overflow-x: auto;
}
.app-section {
  display: none;
  opacity: 0;
  transition: opacity 0.5s ease;
}

.app-section.active {
  display: block;
  opacity: 1;
}
@media (min-width: 1600px) {
  body {
    min-width: 1700px;
  }
  
}
@media (max-width: 850px) {
  body {
    min-width: 700px; 
  }
  .contact-section {
    font-size: 10px !important;
  }
}
/*-----------Header-----------------------------------------------------*/
header {
  padding: 20px 50px;
  background: #fff;
  display: flex;
  justify-content: start;
  align-items: center;
  gap: 10px;
  position: relative;
  z-index: 10;
}
@media (max-width: 850px) {
  header {
    padding: 12px 25px;
  }
}
/*-----------Website Name------------------------------------------------*/
.website-name {
  font-family: "Dancing Script", cursive;
  font-size: 44px;
  font-weight: bold;
  color: black;
  text-decoration: none;
}
@media (min-width: 1600px) {
  .website-name {
    font-size: 50px;
  }
}
@media (max-width: 850px) {
  .website-name {
    font-size: 35px;
  }
  
}
/*----------Search Bar---------------------------------------------------*/
.search-bar {
  display: flex;
  align-items: center;
  width: 30%;
  background: rgb(244, 244, 244);
  border-radius: 25px;
  padding: 5px 5px 5px 20px;
  box-shadow: 0 0 0 transparent;
  transition: all 0.3s ease;
  margin-left: 40px;
  position: relative;
}
.search-bar input {
  flex: 0.99;
  padding: 10px;
  border: none;
  background: transparent;
  outline: none;
  font-size: 14px;
  font-family: "Mona Sans", sans-serif;
}
.search-bar .search-button {
  padding: 0;
  border: none;
  background: transparent;
  cursor: pointer;
}
.search-bar .search-button img {
  width: 32px;
  height: 32px;
  border-radius: 20px;
  transition: all 0.3s ease;
}
.search-bar:hover,
.search-bar .search-btn:hover img {
  transform: scale(1.02);
  box-shadow: 0 0 10px rgba(255, 64, 129, 0.5);
}
@media (min-width: 1600px) {
  .search-bar {
    width: 35%;
  }
  .search-bar input {
    font-size: 16px;
  }
  .search-bar .search-button img {
    width: 36px;
    height: 36px;
  }
}
@media (max-width: 850px) {
  .search-bar {
    width: 10%;
    margin-left: 10px;
    padding: 3px 10px;
    justify-content: center;
  }
  .search-bar input {
    font-size: 14px;
    width: 100%;
  }
  .search-bar input::placeholder {
    color: transparent;
  }
  .search-bar .search-button img {
    width: 30px;
    height: 30px;
    margin-left: 0;
  }
  
}
/*-------------Nút chức năng Header-----------------------------------------------*/
.nav-buttons button {
  padding: 8px 10px;
  margin-left: 5px;
  border: none;
  background: none;
  cursor: pointer;
  color: #000000;
  font-size: 14px;
  font-family: "Mona Sans", sans-serif;
  font-weight: 600;
  transition: all 0.3s ease;
}
.nav-buttons button:hover {
  color: #ff4081;
  transform: scale(1.05);
}
@media (min-width: 1600px) {
  .nav-buttons button {
    font-size: 16px;
  }
}
@media (max-width: 850px) {
  .nav-buttons button {
    font-size: 13px;
    padding: 8px 5px;
  }
}
/*-----------Login Register-----------------------------------------------*/
.login-register {
  display: flex;
  margin-left: auto;
  gap: 10px;
}
.login-register button {
  padding: 12px 10px;
  margin-left: 10px;
  border: none;
  cursor: pointer;
  color: #000000;
  background-color: transparent;
  font-size: 14px;
  font-family: "Mona Sans", sans-serif;
  font-weight: 600;
  border-radius: 30px;
  transition: all 0.3s ease;
}
.login {
  background-color: #000000 !important;
  color: #ffffff !important;
  padding: 10px 20px !important;
}
.login-register button:hover {
  transform: scale(1.05);
  color: rgb(29, 156, 114);
}
@media (min-width: 1600px) {
  .login-register button {
    font-size: 16px;
    padding: 12px 15px;
  }
  .login {
    padding: 12px 25px !important;
  }
}
@media (max-width: 850px) {
  .login-register {
    margin-right: 0;
    gap: 1px;
  }
  .login-register button {
    font-size: 13px;
    padding: 8px 10px;
  }
  .login {
    padding: 10px 13px !important;
  }
  
}
/*---------main content--------------------------------------------*/
#main-content {
  position: relative;
  padding: 0;
  max-width: 100%;
  margin: 0;
  min-height: 100vh;
  overflow: auto;
}
.background-image {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: auto;
  object-fit: cover;
  z-index: 0;
  margin-top: -13vh;
}
/*---------Chữ học từ vựng hiệu quả bằng.....15 phút mỗi ngày-----------------*/
.content-overlay {
  position: relative;
  z-index: 1;
  padding: 110px 50px 0 0;
  text-align: center;
  font-family: "Mona Sans", sans-serif;
}
.content-overlay h2 {
  font-size: 45px;
  margin: 0 0 15px;
  line-height: 1.2;
}
.content-overlay p {
  margin: 0 0 0;
  font-size: 15px;
}
@media (min-width: 1600px) {
  .content-overlay {
    padding: 150px 60px 0 60px;
  }

  .content-overlay h2 {
    font-size: 50px;
    line-height: 1.4;
    margin: 0 0 20px;
  }

  .content-overlay p {
    font-size: 18px;
  }
}
@media (max-width: 850px) {
  .content-overlay {
    padding: 60px 30px 0 30px;
  }

  .content-overlay h2 {
    font-size: 35px;
    line-height: 1.2;
    margin: 0 0 20px;
  }

  .content-overlay p {
    font-size: 13px;
  }
}
/*-----------------3 button chính giữa---------------------------------------*/
.button-main {
  display: flex;
  justify-content: center;
  gap: 20px;
  margin-top: 40px;
}
.button-main button {
  padding: 13px 20px;
  border: none;
  background-color: transparent;
  color: #000000;
  font-size: 15px;
  font-family: "Mona Sans", sans-serif;
  font-weight: 600;
  border-radius: 35px;
  cursor: pointer;
  transition: all 0.3s ease;
  z-index: 2;
}
.button-main button:hover {
  transform: scale(1.05);
  color: #ff4081;
}
.addWord {
  background-color: #000000 !important;
  color: #ffffff !important;
  padding: 13px 30px !important;
}
.practiceButton {
  position: relative;
}

.badge {
  position: absolute;
  top: -5px;
  right: -5px;
  background-color: red;
  color: white;
  font-size: 10px;
  padding: 2px 7px;
  border-radius: 50%;
  display: none; /* Ẩn mặc định */
}
@media (min-width: 1600px) {
  .button-main {
    margin-top: 50px;
  }
  .button-main button {
    font-size: 16px;
    padding: 15px 25px;
  }
  .addWord {
    padding: 15px 35px !important;
  }
}
@media (max-width: 850px) {
  .button-main {
    margin-top: 30px;
  }
  .button-main button {
    font-size: 13px;
    padding: 10px 20px;
  }
  .addWord {
    padding: 14px 20px !important;
  }
}
/*-----------------4 flashcard demo màn hình chính--------------------------*/
.flashcard-container {
  display: flex;
  justify-content: center;
  gap: 40px;
  padding: 50px 0;
  padding-bottom: 30px;
}
.flashcard {
  position: relative;
  width: 160px;
  height: 110px;
  perspective: 1000px;
  cursor: pointer;
  transition: transform 0.3s ease, opacity 0.3s ease;
}
.fade-in {
  animation: fadeIn 0.5s ease;
}

@keyframes fadeIn {
  from {
    opacity: 0;
  }
  to {
    opacity: 1;
  }
}

.front,
.back {
  position: absolute;
  width: 100%;
  height: 100%;
  backface-visibility: hidden;
  transition: transform 0.8s;
  display: flex;
  align-items: center;
  justify-content: center;
  background-color: #fff;
  border-radius: 28px;
  box-shadow: 0 8px 16px rgba(0, 0, 0, 0.4);
  font-size: 20px;
  font-weight: 600;
  color: #000000;
}
.back {
  transform: rotateY(180deg);
  background-color: #ffe6f0;
  color: #000;
}
.flashcard:hover .front {
  transform: rotateY(180deg);
}
.flashcard:hover .back {
  transform: rotateY(360deg);
}
@media (min-width: 1600px) {
  .flashcard-container {
    padding: 90px 0;
  }
  .flashcard {
    width: 210px;
    height: 140px;
  }
  .front,
  .back {
    font-size: 24px;
  }
}
@media (max-width: 850px) {
  .flashcard-container {
    padding: 50px 0;
    gap: 25px;
  }
  .flashcard {
    width: 120px;
    height: 85px;
  }
  .front,
  .back {
    font-size: 16px;
    border-radius: 20px;
  }
}
/*-----------5 button bottom----------------------------------------------*/
.footer-section {
  position: relative;
  margin-top: 2px;
  padding: 0 30px;
}
.footer-content {
  position: relative;
  z-index: 1;
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin: 0 auto;
}
.footer-buttons {
  display: flex;
  gap: 5px;
}
.footer-buttons button {
  padding: 10px 15px;
  border: none;
  background-color: transparent;
  color: #000000;
  font-size: 14px;
  font-family: "Mona Sans", sans-serif;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.3s ease;
}
.footer-buttons button:hover {
  transform: scale(1.05);
  color: #ff4081;
}
@media (min-width: 1600px) {
  .footer-section {
    padding: 0 50px;
  }
  .footer-buttons button {
    font-size: 16px;
    padding: 12px 20px;
  }
}
@media (max-width: 850px) {
  .footer-section {
    padding: 0 20px;
  }
  .footer-buttons button {
    font-size: 12px;
    padding: 12px 10px;
  }
  .footer-buttons {
    gap: 3px;
  }
}
/*--------------Ảnh learn with Revio----------------------------------------*/
.logo-bottom {
  width: 120px;
  padding-right: 30px;
}
.logo-bottom-image {
  width: 100%;
  height: auto;
  object-fit: cover;
  z-index: 10;
}
.logo-bottom.attention {
  animation: attention 2s infinite ease-in-out;
}

@keyframes attention {
  0% {
    transform: scale(1);
  }
  50% {
    transform: scale(1.2); /* Phóng to 1.2 lần */
  }
  100% {
    transform: scale(1);
  }
}
@media (max-width: 850px) {
  .logo-bottom {
    width: 80px;
    padding-right: 30px;
  }
}
/*---------------Vì sao nên học flashcard------------------------*/
.why-flashcard {
  text-align: center;
  padding: 60px 20px;
  background-image: url("image/background2.png");
  background-size: cover;
  background-position: center;
  background-repeat: no-repeat;
}
.why-flashcard h2 {
  font-size: 30px;
  font-weight: 650;
  margin-bottom: 60px;
  position: relative;
  display: inline-block;
}
.why-flashcard h2::after {
  content: "";
  display: block;
  width: 200px;
  height: 6px;
  background-color: #f25ca2;
  margin: 20px auto 0;
  border-radius: 10px;
}
.reason-container {
  display: flex;
  justify-content: center;
  gap: 45px;
  flex-wrap: wrap;
}
.reason-card {
  background-color: #fff;
  border-radius: 20px;
  box-shadow: 0 10px 25px rgba(0, 0, 0, 0.3);
  padding: 50px 20px;
  max-width: 280px;
  transition: transform 0.3s ease;
  font-family: "Mona Sans", sans-serif;
  min-width: 250px;
}
.reason-card:hover {
  transform: translateY(-10px);
}
.reason-card img {
  width: 80px;
  margin-bottom: 16px;
}
.reason-card h3 {
  font-size: 23px;
  font-weight: 700;
  margin-bottom: 12px;
  line-height: 1.4;
}
.reason-card p {
  font-size: 15px;
  color: #444;
  line-height: 1.3;
}
@media (min-width: 1600px) {
  .why-flashcard h2 {
    font-size: 36px;
  }
  .reason-container {
    gap: 60px;
  }
  .reason-card {
    max-width: 320px;
    padding: 60px 30px;
  }
  .reason-card img {
    width: 100px;
  }
  .reason-card h3 {
    font-size: 28px;
  }
  .reason-card p {
    font-size: 18px;
  }
}
@media (max-width: 850px) {
  .why-flashcard {
    padding: 50px 10px;
  }
  .why-flashcard h2 {
    font-size: 22px;
    margin-bottom: 40px;
  }
  .reason-container {
    gap: 30px;
  }
  .reason-card {
    max-width: 220px;
    padding: 30px 15px;
  }
  .reason-card img {
    width: 60px;
  }
  .reason-card h3 {
    font-size: 20px;
  }
  .reason-card p {
    font-size: 13px;
  }
}
/*-------------Đường cong, cơ chế, sự thay đổi------------------------------------*/
.backgroundn {
  position: relative;
  padding: 0;
  max-width: 100%;
  margin: 0;
}
.backgroundn img {
  width: 100%;
}
@media (min-width: 1600px) {
  .backgroundn img {
    width: 100%;
    height: auto;
  }
}
/*----------Modal login, signup------------------------------------------*/
.modal {
  visibility: hidden;
  opacity: 0;
  pointer-events: none;
  display: flex;
  position: fixed;
  inset: 0;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background-color: rgba(0, 0, 0, 0.3);
  z-index: 1000;
  justify-content: center;
  align-items: center;
  transition: opacity 0.3s ease, visibility 0.3s ease;
  will-change: transform, opacity;
}
.modal-content {
  background-color: #fff;
  padding: 40px;
  border-radius: 25px;
  width: 320px;
  max-width: 90%;
  position: relative;
  font-family: "Mona Sans", sans-serif;
  transform: scale(0.2);
  opacity: 0;
  transition: all 0.5s ease, opacity 0.5s ease;
  will-change: transform, opacity;
}
.close {
  position: absolute;
  right: 20px;
  top: 10px;
  font-size: 30px;
  cursor: pointer;
  color: #000;
}
.auth-tabs {
  display: flex;
  border-bottom: 2px solid #f0f0f0;
  margin-bottom: 30px;
}
.tab-button {
  flex: 1;
  padding: 15px;
  border: none;
  background: none;
  font-size: 16px;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.3s ease;
  font-family: "Mona Sans", sans-serif;
}
.tab-button.active {
  color: #ff0055;
  border-bottom: 2px solid #ff0055;
}
.tab-content {
  display: none;
}
.tab-content.active {
  display: block;
}
.tab-content form {
  display: flex;
  flex-direction: column;
  gap: 20px;
}
.tab-content input {
  padding: 15px;
  border: 1px solid #ddd;
  border-radius: 14px;
  font-size: 15px;
  font-family: "Mona Sans", sans-serif;
  box-shadow: 0 10px 25px rgba(0, 0, 0, 0.25);
}
.tab-content button {
  margin-left: 25%;
  padding: 15px;
  max-width: 50%;
  border: none;
  background-color: #3f3e3e;
  color: white;
  border-radius: 14px;
  cursor: pointer;
  font-size: 15px;
  font-weight: 500;
  font-family: "Mona Sans", sans-serif;
  transition: all 0.5s ease;
}
.tab-content button:hover {
  background-color: #000000;
  transform: scale(1.05);
}
.error {
  color: red;
  font-size: 12px;
  min-height: 20px;
}
@media (min-width: 1600px) {
  .modal-content {
    width: 400px;
    padding: 50px;
  }
  .tab-content input {
    font-size: 16px;
    padding: 18px;
  }
  .tab-content button {
    font-size: 16px;
    padding: 18px;
    max-width: 60%;
    margin-left: 20%;
  }
  .close {
    font-size: 35px;
  }
  .auth-tabs {
    margin-bottom: 40px;
  }
  .tab-button {
    font-size: 18px;
  }
  .tab-content form {
    gap: 25px;
  }
  .error {
    font-size: 14px;
  }
}
@media (max-width: 850px) {
  .modal-content {
    width: 50%;
    padding: 10px 30px;
    max-height: 70vh;
    overflow-y: auto;
  }
  .auth-tabs {
    margin-bottom: 0;
  }
  .tab-content form {
    gap: 15px;
  }
  .tab-content h3 {
    font-size: 17px;
    margin-bottom: 0;
  }
  .tab-content input {
    font-size: 13px;
    padding: 12px 20px;
  }
  .tab-content button {
    font-size: 13px;
    padding: 12px;
    max-width: 50%;
    margin-left: 25%;
  }
  .close {
    font-size: 25px;
  }
  .tab-button {
    font-size: 13px;
  }
}
/*----------- Profile review--------------------------------------------- */
.profile-dropdown {
  display: block;
  position: absolute;
  min-width: 400px;
  right: 50px;
  top: 80px;
  background-color: #fff;
  border-radius: 22px;
  box-shadow: 0 10px 20px rgba(0, 0, 0, 0.3);
  padding: 35px;
  z-index: 1000;
  transform: scale(0.4);
  pointer-events: none;
  opacity: 0;
  transition: transform 0.3s ease, opacity 0.3s ease;
  will-change: transform, opacity;
}
.profile-dropdown.show {
  transform: scale(1);
  opacity: 1;
  pointer-events: auto;
}

.profile-content {
  display: flex;
  flex-direction: column;
  gap: 20px;
}

.profile-content input {
  padding: 12px;
  min-width: 59.5%;
  border: 1px solid #ddd;
  border-radius: 13px;
  font-family: "Mona Sans", sans-serif;
  font-size: 14px;
  box-shadow: 0 10px 20px rgba(0, 0, 0, 0.2);
}

.profile-content button {
  width: 33%;
  padding: 12px;
  border: none;
  background-color: #4c4a4a;
  color: white;
  font-family: "Mona Sans", sans-serif;
  border-radius: 12px;
  cursor: pointer;
  font-size: 14px;
  transition: all 0.3s ease;
}

.profile-content button:hover {
  background-color: #000000;
  transform: scale(1.05);
}

.avatar img {
  border-radius: 50%;
  cursor: pointer;
  transition: all 0.3s ease;
}

.avatar img:hover {
  transform: scale(1.1);
}
.modal.active {
  visibility: visible;
  opacity: 1;
  pointer-events: auto;
}

.modal.active .modal-content {
  transform: scale(1);
  opacity: 1;
}
@media (min-width: 1600px) {
  .profile-dropdown {
    min-width: 500px;
    padding: 50px;
    top: 90px;
    right: 60px;
  }
  .profile-content input {
    font-size: 16px;
    padding: 15px;
  }
  .profile-content button {
    font-size: 16px;
    padding: 15px;
    width: 33%;
  }
  .avatar img {
    width: 43px;
    height: 43px;
  }
}
@media (max-width: 850px) {
  .profile-dropdown {
    max-width: 200px;
    padding: 20px;
    top: 65px;
    right: 30px;
    height: 65vh;
    overflow-y: auto;
  }
  .profile-dropdown h3 {
    font-size: 16px;
    margin-bottom: 2px;
  }
  .profile-content input {
    font-size: 13px;
    padding: 12px;
  }
  .profile-content button {
    font-size: 13px;
    padding: 12px;
    width: 31%;
  }
  .avatar img {
    width: 35px;
    height: 35px;
  }
}
/*----------Quên mật khẩu-------------------------------------------------------*/
.forgot-password {
  text-align: right;
}

.forgot-password a {
  font-size: 14px;
  color: #008c17ae;
  text-decoration: none;
  cursor: pointer;
}
@media (min-width: 1600px) {
  .forgot-password a {
    font-size: 16px;
  }
}
@media (max-width: 850px) {
  .forgot-password a {
    font-size: 13px;
  }
}
/*------------------Section Thêm từ------------------------------------------------------ */
#add-word-section {
  position: relative;
  min-width: 100vw;
  overflow-x: hidden;
  max-height: 100vh;
  overflow-y: hidden;
}
#add-word-section .background-img {
  width: 100%;
  height: auto;
  display: block;
}

.add-word-content {
  position: absolute;
  top: 0;
  left: -35px;
  width: 100%;
  padding-top: 15px;
  display: flex;
  flex-direction: column;
  align-items: center;
}

/* Bảng */
.word-table-container {
  min-height: 65vh;
  max-height: 65vh;
  overflow-y: auto;
  width: 60%;
  background: transparent;
}

.word-table {
  border-collapse: separate;
  border-spacing: 0;
  width: 100%;
  font-family: "Mona Sans", sans-serif;
  table-layout: fixed;
}

.word-table thead tr {
  background-color: white;
  border-radius: 12px;
  font-size: 15px;
}
.word-table th {
  position: relative;
  width: 25%;
  padding: 10px 10px;
  text-align: center;
  border-top: 2px solid #000;
  border-bottom: 2px solid #000;
}


.word-table th:not(:first-child)::before {
  content: "";
  position: absolute;
  top: 10%;
  bottom: 10%;
  left: 0;
  width: 1.5px;
  background: #000;
}

.word-table th:first-child {
  border-left: 2px solid #000;
  border-top-left-radius: 13px;
  border-bottom-left-radius: 13px;
}

.word-table th:last-child {
  border-right: 2px solid #000;
  border-top-right-radius: 13px;
  border-bottom-right-radius: 13px;
}

.word-table td {
  position: relative;
  padding: 9px;
  text-align: center;
  border-bottom: 1px solid #000;
}

.word-table td:not(:first-child)::before {
  content: "";
  position: absolute;
  top: 10%;
  bottom: 10%;
  left: 0;
  width: 1px;
  background: #000;
}
.word-table th:nth-child(1),
.word-table td:nth-child(1) {
  width: 25%;
}

.word-table th:nth-child(2),
.word-table td:nth-child(2) {
  width: 10%;
}

.word-table th:nth-child(3),
.word-table td:nth-child(3) {
  width: 25%;
}

.word-table th:nth-child(4),
.word-table td:nth-child(4) {
  width: 40%;
}
.word-table input {
  width: 100%;
  border: none;
  outline: none;
  background: transparent;
  text-align: center;
  font-size: 15px;
  font-family: "Mona Sans", sans-serif;
}

/* Nút */
.addWordsection-buttons {
  position: relative;
  left: 20px;
  width: 100%;
  display: flex;
  justify-content: space-between;
  padding-top: 55px;
  z-index: 10;
  pointer-events: auto;
  margin-bottom: 0px;
}

.addWordsectionCenter-buttons {
  display: flex;
  gap: 20px;
  margin: 0 auto;
}

.addWordsectionAdd,
.addWordsectionSave,
.addWordsectionQuit {
  min-width: 90px;
  padding: 12px 18px;
  font-size: 14px;
  font-family: "Mona Sans", sans-serif;
  font-weight: 500;
  border: none;
  border-radius: 25px;
  background-color: #353535;
  color: #fff;
  cursor: pointer;
  box-shadow: 0 10px 20px rgba(0, 0, 0, 0.3);
  transition: all 0.3s ease;
}

.addWordsectionQuit {
  background-color: #353535;
  margin-right: 80px;
}
.addWordsectionSave {
  background-color: #076e18ae;
}
.addWordsectionAdd:hover,
.addWordsectionQuit:hover {
  transform: scale(1.05);
  background-color: #000;
}
.addWordsectionSave:hover {
  transform: scale(1.05);
  background-color: #086517ae;
}
@media (min-width: 1600px) {
  .addWordsection-buttons {
    padding-top: 100px;
    margin-bottom: 20px;
  }
  .addWordsectionAdd,
  .addWordsectionSave,
  .addWordsectionQuit {
    min-width: 120px;
    padding: 14px 20px;
    font-size: 16px;
  }
  .addWordsectionQuit {
    margin-right: 100px;
  }
}
@media (max-width: 850px) {
  .addWordsection-buttons {
    padding-top: 40px;
  }
  .addWordsectionAdd,
  .addWordsectionSave,
  .addWordsectionQuit {
    min-width: 70px;
    padding: 12px 18px;
    font-size: 12px;
  }
  .addWordsectionQuit {
    margin-right: 20px;
  }
  .word-table thead tr {
    font-size: 11px;
  }
  .word-table input {
    font-size: 12px;
  }
}
/*------------------ Section quản lý thẻ-------------------------------------------------------- */

#manage-flashcard-section {
  position: relative;
  min-width: 100vw;
  overflow-x: hidden;
  max-height: 100vh;
  overflow-y: hidden;
}
#manage-flashcard-section .background-img {
  width: 100%;
  height: auto;
  display: block;
}
.word-table th:nth-child(5),
.word-table td:nth-child(5) {
  width: 9%;
}
.word-table th:nth-child(6),
.word-table td:nth-child(6) {
  width: 5%;
}
.search-flashcard-input-section {
  padding: 12px 18px;
  border: solid 1px #ddd;
  background-color: #ffffff;
  outline: none;
  font-size: 15px;
  font-family: "Mona Sans", sans-serif;
  border-radius: 25px;
  min-width: 100%;
  box-shadow: 0 10px 20px rgba(0, 0, 0, 0.2);
  transition: all 0.3s ease;
}
.search-flashcard-input-section:hover {
  transform: scale(1.05);
}
.RemoveWord {
  min-width: 70px;
  padding: 12px 20px;
  font-size: 14px;
  font-family: "Mona Sans", sans-serif;
  font-weight: 500;
  border: none;
  border-radius: 25px;
  background-color: #e54242;
  color: #fff;
  cursor: pointer;
  box-shadow: 0 10px 20px rgba(0, 0, 0, 0.3);
  transition: all 0.3s ease;
}
.RemoveWord:hover {
  transform: scale(1.05);
  background-color: #b60000;
}
.tooltip-container {
  position: relative;
}

.tooltip-popup {
  display: none;
  position: absolute;
  top: -35px;
  left: 50%;
  transform: translateX(-50%);
  background: #e0c3c3;
  color: #3d3c3c;
  padding: 5px 8px;
  border-radius: 5px;
  font-size: 13px;
  white-space: nowrap;
  z-index: 100;
}

.tooltip-container:hover .tooltip-popup {
  display: block;
}
@media (min-width: 1600px) {
  .tooltip-popup {
    font-size: 14px;
  }
}
@media (max-width: 850px) {
  .tooltip-popup {
    font-size: 11px;
  }
  .search-flashcard-input-section {
    padding: 10px 18px;
    font-size: 12px;
    min-width: 50%;
  }
  .RemoveWord {
    min-width: 70px;
    padding: 12px 20px;
    font-size: 12px;
  }
  .word-table th:nth-child(2),
  .word-table td:nth-child(2) {
    width: 10%;
  }
  .word-table th:nth-child(5),
  .word-table td:nth-child(5) {
    width: 10%;
    font-size: 12px;
  }
  .word-table th:nth-child(6),
  .word-table td:nth-child(6) {
    width: 8%;
  }
}
/*-----------------Section ôn luyện------------------------------------------------------ */
#practice-section {
  position: relative;
  min-width: 100vw;
  overflow-x: hidden;
  max-height: 100vh;
  overflow-y: hidden;
  display: flex;
  justify-content: center;
  align-items: center;
}
#practice-section .background-img {
  width: 100%;
  height: auto;
  display: block;
}
.card-columns-wrapper {
  position: absolute;
  top: 0;
  left: -35px;
  display: flex;
  justify-content: center;
  flex-direction: row;
  align-items: center;
  gap: 60px;
  z-index: 1;
  width: 100%;
  margin-top: 80px;
}


.card-column {
  display: flex;
  flex-direction: column;
  align-items: center;
}


.card-stack {
  position: relative;
  width: 250px;
  height: 350px;
}
.big-card-stack {
  width: 250px;
  height: 350px;
}
.small-card-stack {
  width: 210px;
  height: 290px;
}

#practice-section .card.shadow {
  position: absolute;
  width: 100%;
  height: 100%;
  background: white;
  border-radius: 12px;
  box-shadow: 0 10px 20px rgba(0, 0, 0, 0.3);
  top: 0;
  left: 0;
}
#practice-section .card.shadow h3 {
  margin-bottom: 10px;
  font-size: 16px;
  font-weight: 700;
  color: #565555;
  text-align: center;
}


#practice-section .card.main-card {
  position: absolute;
  width: 73%;
  height: 66%;
  top: 57%;
  left: 50%;
  transform: translate(-50%, -50%);
  background: white;
  border-radius: 13px;
  padding: 16px;
  text-align: center;
  box-shadow: 0 8px 25px rgba(0, 0, 0, 0.2);
  z-index: 2;
}


#practice-section .card-content.count {
  font-size: 22px;
  font-weight: 700;
  margin-top: 50%;
  color: #565555;
}


#practice-section .flip-card {
  position: absolute;
  width: 88%;
  height: 80%;
  top: 57%;
  left: 50%;
  transform: translate(-50%, -50%);
  perspective: 1000px;
  z-index: 2;
  cursor: pointer;
}

#practice-section .flip-card-inner {
  position: relative;
  width: 100%;
  height: 100%;
  transform-style: preserve-3d;
  transition: transform 0.6s;
  will-change: transform;
}

#practice-section .flip-card:hover .flip-card-inner {
  transform: rotateY(180deg);
}

#practice-section .flip-card-front,
#practice-section .flip-card-back {
  position: absolute;
  width: 100%;
  height: 100%;
  backface-visibility: hidden;
  background: white;
  border-radius: 13px;
  box-shadow: 0 8px 25px rgba(0, 0, 0, 0.2);
  padding: 16px;
  text-align: center;
  display: flex;
  flex-direction: column;
  justify-content: center;
  box-sizing: border-box;
}

#practice-section .flip-card-front {
  background: white;
}

#practice-section .flip-card-back {
  background: #ffffff;
  transform: rotateY(180deg);
}


#practice-section .card-word {
  font-size: 22px;
  font-weight: 650;
  margin-bottom: 6px;
}

#practice-section .card-type {
  font-size: 13px;
  font-style: italic;
  color: #666;
}

#practice-section .card-meaning {
  font-size: 22px;
  font-weight: 650;
  margin-bottom: 8px;
}

#practice-section .card-example {
  font-size: 13px;
  color: #333;
}
#practice-section .flip-card,
#practice-section .flip-card-front,
#practice-section .flip-card-back {
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  text-rendering: optimizeLegibility;
}
.bottom-buttons {
  position: absolute;
  bottom: 100px;
  left: 47.5%;
  transform: translateX(-50%);
  display: flex;
  justify-content: center;
  gap: 20px;
  z-index: 10;
  width: 100%;
}
.practice-controls {
  display: flex;
  gap: 20px;
  margin: 0 auto;
}
.practice-btn {
  padding: 12px 18px;
  min-width: 120px;
  border: none;
  border-radius: 25px;
  font-size: 14px;
  font-weight: 500;
  cursor: pointer;
  color: #fff
  font-family: "Mona Sans", sans-serif;
  box-shadow: 0 10px 20px rgba(0, 0, 0, 0.3);
  transition: all 0.3s ease;
}

.btn-wrong {
  font-family: "Mona Sans", sans-serif;
  background-color: #f44336;
  color: white;
}
.btn-wrong:hover {
  background-color: #c12929;
  transform: scale(1.05);
}

.btn-skip {
  font-family: "Mona Sans", sans-serif;
  background-color: #ff9800;
  color: white;
}
.btn-skip:hover {
  background-color: #e68004;
  transform: scale(1.05);
}

.btn-correct {
  font-family: "Mona Sans", sans-serif;
  background-color: #47a74a;
  color: white;
}
.btn-correct:hover {
  background-color: #388e3c;
  transform: scale(1.05);
}
.exit-btn {
  min-width: 100px;
  padding: 12px 18px;
  font-family: "Mona Sans", sans-serif;
  position: absolute;
  right: 50px;
  font-size: 14px;
  font-weight: 500;
  background: transparent;
  border: none;
  border-radius: 25px;
  cursor: pointer;
  color: #ffffff;
  z-index: 5;
  transition: all 0.3s ease;
  box-shadow: 0 10px 20px rgba(0, 0, 0, 0.3);
  background-color: #434242;
}

.exit-btn:hover {
  color: #000;
  transform: scale(1.05);
}
@media (min-width: 1600px) {
  .card-columns-wrapper {
    gap: 60px;
    margin-top: 120px;
  }
  .card-stack {
    width: 300px;
    height: 420px;
  }
  .big-card-stack {
    width: 300px;
    height: 420px;
  }
  .small-card-stack {
    width: 260px;
    height: 350px;
  }
  #practice-section .card.main-card {
    width: 75%;
    height: 70%;
    top: 56%;
    left: 50%;
    transform: translate(-50%, -50%);
  }
  #practice-section .card-content.count {
    font-size: 26px;
    margin-top: 45%;
  }
  #practice-section .flip-card {
    width: 88%;
    height: 80%;
    top: 55%;
    left: 50%;
    transform: translate(-50%, -50%);
  }
  #practice-section .card-word {
    font-size: 26px;
  }
  #practice-section .card-type {
    font-size: 16px;
  }
  #practice-section .card-meaning {
    font-size: 26px;
  }
  #practice-section .card-example {
    font-size: 16px;
  }
  .bottom-buttons {
    bottom: 100px;
    left: 48%;
    transform: translateX(-50%);
  }
  .practice-controls {
    gap: 30px;
  }
  .practice-btn {
    padding: 14px 20px;
    min-width: 140px;
    font-size: 16px;
  }
  .exit-btn {
    min-width: 120px;
    padding: 14px 20px;
    font-size: 16px;
    right: 70px;
  }
  .btn-wrong {
    font-size: 16px;
    padding: 14px 20px;
  }
  .btn-skip {
    font-size: 16px;
    padding: 14px 20px;
  }
  .btn-correct {
    font-size: 16px;
    padding: 14px 20px;
  }
}
@media (max-width: 850px) {
  .card-columns-wrapper {
    gap: 20px;
    margin-top: 2px;
  }
  .card-stack {
    width: 150px;
    height: 200px;
  }
  .big-card-stack {
    width: 150px;
    height: 200px;
  }
  .small-card-stack {
    width: 110px;
    height: 150px;
  }
  #practice-section .card.shadow {
  border-radius: 9px;
}
  #practice-section .card.shadow h3 {
    font-size: 12px !important;
  }
  #practice-section .card.main-card {
    width: 55%;
    height: 55%;
    top: 57%;
    left: 50%;
    transform: translate(-50%, -50%);
    border-radius: 6px;
  }
  #practice-section .card-content.count {
    font-size: 13px;
    margin-top: 45%;
  }
  #practice-section .flip-card-front,
  #practice-section .flip-card-back {
    border-radius: 6px;
  }
  #practice-section .flip-card {
    width: 88%;
    height: 75%;
    top: 58%;
    left: 50%;
  }
  #practice-section .card-word {
    font-size: 20px;
  }
  #practice-section .card-type {
    font-size: 12px;
  }
  #practice-section .card-meaning {
    font-size: 20px;
  }
  #practice-section .card-example {
    font-size: 11px;
  }
  .bottom-buttons {
    position: static;
    margin-top: -120px;
    margin-left: -70px;
    transform: none;        
    width: auto;
    justify-content: flex-start;
  }
  .practice-controls {
    gap: 30px;
  }
  .practice-btn {
    padding: 10px 15px;
    min-width: 90px;
    font-size: 12px;
  }
  .exit-btn {
    min-width: 90px;
    padding: 12px 15px;
    font-size: 12px;
    right: 20px;
  }
  .btn-wrong {
    font-size: 12px;
    padding: 12px 15px;
  }
  .btn-skip {
    font-size: 12px;
    padding: 12px 15px;
  }
  .btn-correct {
    font-size: 12px;
    padding: 12px 15px;
  }
}
/*----------------Model search---------------------------------------------------------*/
.search-results {
  background-color: #fff;
  border: 1px solid #ddd;
  border-radius: 20px;
  margin-top: 10px;
  margin-left: -20px;
  padding: 10px 15px;
  max-height: 600px;
  min-width: 30vw;
  overflow-y: auto;
  font-family: "Mona Sans", sans-serif;
  box-shadow: 0 8px 20px rgba(0, 0, 0, 0.2);
  position: absolute;
  top: 100%;
  z-index: 999;
  display: none;
  padding: 6px 4px;
  border-bottom: 1px solid #f1f1f1;
  font-size: 14px;
}

.search-results .result-item {
  padding: 10px 15px;
  border-bottom: 1px solid #f1f1f1;
  font-size: 15px;
}

.search-results .result-item:last-child {
  border-bottom: none;
}
@media (min-width: 1600px) {
  .search-results {
    max-height: 800px;
    padding: 15px 20px;
    font-size: 16px;
  }
  .search-results .result-item {
    padding: 12px 18px;
    font-size: 16px;
  }
}
@media (max-width: 850px) {
  .search-results {
    margin-left: 0;
    left: 0;
    max-height: 65vh;
    overflow-y: auto;
    min-width: 40vw;
    padding: 12px 10px;
    font-size: 12px;
  }
  .search-results .result-item {
    padding: 10px 10px;
    font-size: 13px;
  }
}

::-webkit-scrollbar {
  width: 8px; /* Độ rộng dọc */
  height: 8px; /* Độ rộng ngang */
}

::-webkit-scrollbar-thumb {
  background-color: #b6b6b6; /* Màu hồng nhạt */
  border-radius: 10px;
}

::-webkit-scrollbar-track {
  background: transparent; /* Màu nền thanh cuộn */
}


.wod-modal {
  display: none;
  position: fixed;
  z-index: 9999;
  left: 0; top: 0;
  width: 100%; height: 100%;
  background: rgba(0,0,0,0.5);
}
.wod-modal-content {
  background: #fff;
  padding: 20px;
  margin: 10% auto;
  width: 90%;
  max-width: 400px;
  border-radius: 8px;
}
.wod-close-modal {
  float: right;
  font-size: 20px;
  cursor: pointer;
}