.box-header {
    background-color: #fff;
    margin-bottom: 5px;
  }
  /* bredcrump */
  .breadcrumb {
    padding: 20px 0 15px;
  }
  
  .breadcrumb ul {
    display: flex;
    flex-wrap: wrap;
    list-style: none;
    margin: 0;
    padding: 0;
  }
  
  .breadcrumb li:not(:last-child)::after {
    display: inline-block;
    margin: 0 10px;
    content: "\f104";
    font-family: "Font Awesome 6 Free";
    font-weight: 900;
    font-size: 10px;
  }
  /* vertical tab */
  .tab-nav {
    width: 250px;
    float: right;
  }
  .tabcontent {
    display: none;
    padding: 0;
    border-top: none;
    min-height: 400px;
  }
  .weight-tabs {
    position: relative;
    overflow: hidden;
    margin-bottom: 30px;
  }
  .tab-container {
    position: relative;
    background: #ffffff;
    box-shadow: 0px 4px 16px rgb(0 0 0 / 8%);
    border-radius: 8px;
    margin-bottom: 30px;
    padding: 30px;
    margin-right: 270px;
  }
  .tab {
    overflow: hidden;
    /* border-radius: 16px;
    background-color: #f3f3f4;
    transition: all 3s; */
  }
  .tab button {
    background-color: inherit;
    border: none;
    outline: none;
    cursor: pointer;
    padding: 12px 16px;
    transition: 0.3s;
    /* font-size: 1.125rem; */
    float: right;
    clear: both;
    width: 230px;
    display: flex;
    margin-bottom: 10px;
    align-items: center;
    border: 4px solid transparent;
    border-radius: 16px;
    background-color: #f3f3f4;
    text-align: center;
    margin: 5px auto;
  }
  .tab button img {
    max-width: 20px;
    vertical-align: middle;
    margin-left: 20px;
  }
  .tab button:hover {
  }
  .tab button.active {
    border: 4px solid #ef3e44;
    color: #ef3e44;
  }
  .tab button.active:before {
    content: "";
    height: 100%;
    width: 4px;
    color: #ef3e44;
  }
  .is-hidden {
    display: none !important;
  }
  .is-desktop {
    display: block;
  }
  .box-select {
    margin: 20px 0;
  }
  .box-select label {
    position: relative;
    bottom: 6px;
    font-weight: 700;
  }
  .customselect-side {
    cursor: pointer;
    font-size: 14px;
    background: #f3f3f4;
    border-radius: 8px;
    position: relative;
    z-index: 1000;
    outline: 0;
    width: 100%;
    display: inline-block;
  }
  .customselect-side select {
    display: flex;
  
    cursor: pointer;
    font-size: 14px;
    padding: 10px 27px;
    background: #f3f3f4;
    border-radius: 8px;
    position: relative;
    z-index: 1000;
    outline: 0;
    display: block;
    width: 100%;
  }
  .tabcontent input[type="submit"] {
    width: 100%;
    background-color: #ef3e44;
    color: white;
    padding: 14px 20px;
    margin: 8px 0;
    border: none;
    border-radius: 4px;
    cursor: pointer;
    float: left;
  }
  .calculate-aside input[type="submit"]:hover {
    background-color: #ef3e44;
  }
  
  select {
    -webkit-appearance: none;
    -moz-appearance: none;
    appearance: none;
    width: 100%;
    padding: 1rem;
    font-size: 1.125rem;
    background-color: #f0f0f0;
    border: none;
  }
  select::-ms-expand {
    display: none;
  }
  .select {
    position: relative;
    max-width: 60%;
  }
  .box-weight {
    background: #ffffff;
    box-shadow: 0px 4px 16px rgba(0, 0, 0, 0.08);
    border-radius: 8px;
    margin-bottom: 10px;
    padding: 20px 30px;
    align-items: center;
  }
  .box-weight h1 {
    display: none;
  }
  .box-weight .tab {
    overflow: hidden;
    transition: all 3s;
  }
  .box-weight .tab button {
    background-color: inherit;
    float: right;
    border: none;
    outline: none;
    cursor: pointer;
    padding: 12px 15px;
    transition: 0.3s;
    border: 4px solid transparent;
    background-color: #f3f3f4;
    font-weight: 600;
  }
  
  .tab button.active {
    border: 4px solid #ef3e44;
  }
  
  .is-hidden {
    display: none !important;
  }
  .is-desktop {
    display: block;
  }
  .is-mobile {
    display: none !important;
  }
  .label-mobile {
    display: none;
  }
  
  .tabcontent button.submit {
    background: #ef3e44;
    border-radius: 8px;
    padding: 17px 20px;
    color: #fff;
    width: 48%;
  }
  
  .custom-select {
    position: absolute;
    margin-top: 10px;
    width: 30%;
  }
  
  .custom-select select {
    display: none;
  }
  
  .select-selected {
    background-color: #f3f3f4;
    border-radius: 5px;
    color: #919191;
  }
  
  .select-selected:after {
    position: absolute;
    content: "";
    top: 10px;
    left: 7px;
    width: 0;
    height: 0;
    border: 6px solid transparent;
    border-color: #919191 transparent transparent transparent;
  }
  
  .select-selected.select-arrow-active:after {
    border-color: transparent transparent #919191 transparent;
    top: 7px;
  }
  .select-items div,
  .select-selected {
    color: #919191;
    padding: 7px 8px;
    border: 1px solid transparent;
    border-color: transparent transparent rgba(0, 0, 0, 0.1) transparent;
    cursor: pointer;
    font-size: 12px;
  }
  .box-filter {
    background-color: #fff;
    border-radius: 22px;
    position: relative;
    bottom: 50px;
    padding: 30px;
    min-height: 55px;
  }
  .title-tab {
    font-size: 20px;
    margin-bottom: 30px;
  }
  .tabcontent button.submit {
    width: 60%;
    margin-top: 15px;
  }
  .tabcontent .box-input {
    margin: 15px 0;
  }
  .tabcontent .box-input .customselect {
    margin-top: 10px;
  }
  .tabcontent .box-input label {
    font-size: 13px;
    font-weight: 700;
  }
  .tabcontent .box-input select {
    border-radius: 8px;
    max-width: 100%;
    outline: 0;
  }
  .select:after {
    content: "\f107";
    font-family: "Font Awesome 6 Free";
    font-weight: 900;
    position: absolute;
    top: 66%;
    transform: translateY(-50%);
    left: 0.1rem;
    pointer-events: none;
    width: 30px;
    height: 32px;
    font-size: 15px;
  }
  @media (max-width: 768px) {
    .is-mobile {
      display: block !important;
      outline: 0;
      background-color: #f3f3f4;
      width: 100%;
      padding: 20px;
      border-radius: 8px;
      margin-bottom: 20px;
    }
    .is-desktop {
      display: none !important;
    }
    .box-weight {
      padding: 20px 15px;
    }
    .tab-nav {
      display: none;
    }
    .tab-container {
      margin-right: 0;
      margin-bottom: 20px;
    }
  
    .box-weight h1 {
      display: block;
      padding: 20px 30px;
      border-bottom: 1px solid #f3f3f4;
    }
  
    .box-weight {
      background: #ffffff;
      box-shadow: 0px 4px 16px rgb(0 0 0 / 8%);
      border-radius: 8px;
      margin-bottom: 10px;
      padding: 20px 20px;
      align-items: center;
    }
  
    .tabcontent {
      display: none;
      padding: 20px;
      position: relative;
      background: white;
      width: 100%;
      margin-right: 0;
      min-height: auto;
    }
    .tabcontent input[type="submit"] {
      padding: 14px 20px;
      float: none;
      outline: 0;
    }
    .customselect {
      display: flex;
      align-items: center;
      gap: 12px;
      cursor: pointer;
      font-size: 14px;
      padding-left: 10px;
      border-radius: 8px;
      position: relative;
      z-index: 1000;
      outline: 0;
      margin-left: 6px;
      width: min-content;
      display: inline-block;
      background-color: #f3f3f4;
      border-radius: 8px;
      width: 100%;
      border: transparent;
      outline: 0;
    }
    .select:after {
      content: "\f107";
      font-family: "Font Awesome 6 Free";
      font-weight: 900;
      position: absolute;
      top: 66%;
      transform: translateY(-50%);
      left: 0.1rem;
      pointer-events: none;
      width: 30px;
      height: 32px;
      font-size: 15px;
    }
    .select {
      position: relative;
      max-width: 100%;
    }
    .tabcontent .box-input select {
      width: 100%;
      max-width: 100%;
      outline: 0;
    }
    .tabcontent button.submit {
      width: 100%;
      margin-top: 15px;
    }
  }
  
  /* bottom box */
  .bottom-box {
    position: relative;
    min-height: 360px;
    clear: both;
    background: #ffffff;
    box-shadow: 0px 4px 16px rgba(0, 0, 0, 0.08);
    border-radius: 8px;
    margin-bottom: 10px;
    margin-top: 30px;
    padding: 30px;
    align-items: center;
  }
  .bottom-box a {
    display: block;
  }
  .bottom-box .colomn {
    background: #f8f8f8;
    border-radius: 16px;
    padding: 20px 30px;
    display: flex;
    align-items: center;
    margin-bottom: 15px;
    justify-content: space-between;
  }
  .bottom-box .colomn img {
    max-width: 20px;
  }
  .bottom-box .box-center {
    position: relative;
    left: 20%;
  }
  
  @media (max-width: 450px) {
    .bottom-box {
      padding: 30px 20px;
    }
    .bottom-box .colomn {
      padding: 20px 15px;
    }
    .bottom-box .box-center {
      position: relative;
      left: 12%;
    }
  }
  
/* Result box styling */
.result-box {
  background: #f8f9fa;
  border: 2px solid #28a745;
  border-radius: 8px;
  padding: 20px;
  margin-top: 20px;
  display: none;
}

.result-box.show {
  display: block;
  animation: fadeIn 0.3s ease-in;
}

@keyframes fadeIn {
  from { opacity: 0; transform: translateY(-10px); }
  to { opacity: 1; transform: translateY(0); }
}

.result-box h3 {
  color: #28a745;
  margin-bottom: 15px;
  font-size: 18px;
}

.result-box .result-item {
  display: flex;
  justify-content: space-between;
  margin-bottom: 10px;
  padding: 8px 0;
  border-bottom: 1px solid #e9ecef;
}

.result-box .result-item:last-child {
  border-bottom: none;
  font-weight: bold;
  font-size: 16px;
  color: #ef3e44;
}

.result-box .result-label {
  font-weight: 600;
  color: #495057;
}

.result-box .result-value {
  font-weight: 500;
  color: #212529;
}

/* Input styling improvements */
.customselect, 
.box-input input[type="number"], 
.box-input select {
  width: 100%;
  padding: 12px 15px;
  font-size: 14px;
  border: 2px solid #f3f3f4;
  border-radius: 8px;
  background-color: #f3f3f4;
  outline: none;
  transition: all 0.3s ease;
  font-family: inherit;
}

.customselect:focus, 
.box-input input[type="number"]:focus, 
.box-input select:focus {
  border-color: #ef3e44;
  background-color: #fff;
  box-shadow: 0 0 0 3px rgba(239, 62, 68, 0.1);
}

.box-input input[type="number"]::placeholder {
  color: #6c757d;
}

/* Error styling */
.input-error {
  border-color: #dc3545 !important;
  background-color: #fff5f5 !important;
}

.error-message {
  color: #dc3545;
  font-size: 12px;
  margin-top: 5px;
  display: none;
}

.error-message.show {
  display: block;
}

/* Mobile improvements */
@media (max-width: 768px) {
  .result-box {
    padding: 15px;
    margin-top: 15px;
  }
  
  .result-box h3 {
    font-size: 16px;
  }
  
  .result-box .result-item {
    flex-direction: column;
    gap: 5px;
  }
  
  .result-box .result-item:last-child {
    flex-direction: row;
    justify-content: space-between;
  }
}

/* Rebar Information Content Styles */
.rebar-info-content {
  margin-top: 40px;
  padding-top: 30px;
  border-top: 2px solid #f3f3f4;
}

/* Beam Information Content Styles */
.beam-info-content {
  margin-top: 40px;
  padding-top: 30px;
  border-top: 2px solid #f3f3f4;
}

/* Pipe Information Content Styles */
.pipe-info-content {
  margin-top: 40px;
  padding-top: 30px;
  border-top: 2px solid #f3f3f4;
}

/* Sheet Information Content Styles */
.sheet-info-content {
  margin-top: 40px;
  padding-top: 30px;
  border-top: 2px solid #f3f3f4;
}

/* Angle Information Content Styles */
.angle-info-content {
  margin-top: 40px;
  padding-top: 30px;
  border-top: 2px solid #f3f3f4;
}

/* Channel Information Content Styles */
.channel-info-content {
  margin-top: 40px;
  padding-top: 30px;
  border-top: 2px solid #f3f3f4;
}

.purlin-info-content {
  margin-top: 40px;
  padding-top: 30px;
  border-top: 2px solid #f3f3f4;
}

/* Channel Calculation Section Styles */
.calculation-section {
  background: #f9f9f9;
  border: 1px solid #e0e0e0;
  border-radius: 8px;
  padding: 20px;
  margin-bottom: 30px;
}

.calculation-section h3 {
  color: #333;
  margin-bottom: 20px;
  font-size: 18px;
  padding-bottom: 0;
}

.calc-row {
  display: flex;
  flex-wrap: wrap;
  gap: 15px;
  align-items: end;
}

.calc-row .box-input {
  flex: 1;
  min-width: 200px;
}

.calc-row .submit {
  flex-shrink: 0;
  margin-top: 0;
}

/* Result Details Styling */
.result-details {
  background: #f0f8ff;
  border: 1px solid #007bff;
  border-radius: 6px;
  padding: 15px;
  margin-top: 15px;
}

.result-details p {
  margin: 8px 0;
  font-size: 14px;
  color: #333;
}

.result-details p:last-child {
  font-size: 16px;
  font-weight: bold;
  color: #007bff;
  border-top: 1px solid #ddd;
  padding-top: 10px;
  margin-top: 15px;
}

.info-section {
  margin-bottom: 20px;
  padding: 15px 0;
}

.info-section h3 {
  color: #ef3e44;
  font-size: 20px;
  font-weight: 700;
  margin-bottom: 15px;
  border-bottom: 2px solid #ef3e44;
  padding-bottom: 8px;
  display: inline-block;
}

.info-section p {
  font-size: 14px;
  line-height: 1.8;
  color: #333;
  margin-bottom: 15px;
  text-align: justify;
}

.info-section ul {
  margin: 15px 0;
  padding-right: 20px;
  list-style-type: disc;
  list-style-position: outside;
}

.info-section ul li {
  font-size: 14px;
  line-height: 1.8;
  color: #333;
  margin-bottom: 12px;
  text-align: justify;
  display: list-item;
  padding-right: 5px;
}

.info-section ul li strong {
  color: #ef3e44;
  font-weight: 700;
}

/* Table Styles */
.table-responsive {
  overflow-x: auto;
  margin: 20px 0;
  border-radius: 8px;
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
}

.weight-table {
  width: 100%;
  border-collapse: collapse;
  background: white;
  font-size: 13px;
}

.weight-table thead {
  background: #ef3e44;
  color: white;
}

.weight-table thead th {
  padding: 12px 8px;
  text-align: center;
  font-weight: 700;
  font-size: 12px;
}

.weight-table tbody tr {
  border-bottom: 1px solid #f3f3f4;
}

.weight-table tbody tr:nth-child(even) {
  background: #f9f9f9;
}

.weight-table tbody tr:hover {
  background: #fff5f5;
}

.weight-table tbody td {
  padding: 10px 8px;
  text-align: center;
  color: #333;
  font-weight: 500;
}

.engineering-table thead th {
  font-size: 11px;
  padding: 10px 6px;
}

.engineering-table tbody td {
  font-size: 12px;
  padding: 8px 6px;
}

/* Formula and Example Boxes */
.formula-box {
  background: linear-gradient(135deg, #ef3e44, #d63384);
  color: white;
  padding: 20px;
  border-radius: 10px;
  margin: 20px 0;
  text-align: center;
  box-shadow: 0 4px 15px rgba(239, 62, 68, 0.3);
}

.formula-box p {
  font-size: 16px;
  font-weight: 700;
  margin: 0;
  color: white !important;
}

.example-box {
  background: #f8f9fa;
  border: 2px solid #28a745;
  border-radius: 8px;
  padding: 20px;
  margin: 20px 0;
}

.example-box p {
  font-size: 14px;
  color: #333 !important;
  margin-bottom: 10px;
  font-weight: 600;
}

.example-box p:last-child {
  margin-bottom: 0;
  color: #28a745 !important;
}

/* Pipe Table Special Styling */
.pipe-table {
  font-size: 12px;
}

.pipe-table thead th {
  font-size: 11px;
  padding: 10px 6px;
}

.pipe-table tbody td {
  font-size: 11px;
  padding: 8px 6px;
}

/* Mobile Responsive for Info Content */
@media (max-width: 768px) {
  .rebar-info-content,
  .beam-info-content,
  .pipe-info-content,
  .sheet-info-content,
  .angle-info-content,
  .channel-info-content {
    margin-top: 30px;
    padding-top: 20px;
  }

  .purlin-info-content {
    margin-top: 30px;
    padding-top: 20px;
  }
  
  .info-section {
    margin-bottom: 15px;
    padding: 10px 0;
  }
  
  .info-section h3 {
    font-size: 18px;
    margin-bottom: 12px;
  }
  
  .info-section p {
    font-size: 13px;
    line-height: 1.7;
  }
  
  .info-section ul li {
    font-size: 13px;
    line-height: 1.7;
    margin-bottom: 10px;
    display: list-item;
    padding-right: 5px;
  }

  /* Mobile styles for calculation sections */
  .calculation-section {
    padding: 15px;
    margin-bottom: 20px;
  }

  .calculation-section h3 {
    font-size: 16px;
    margin-bottom: 15px;
    padding-bottom: 0;
  }

  .calc-row {
    flex-direction: column;
    gap: 10px;
  }

  .calc-row .box-input {
    min-width: auto;
  }

  .calc-row .submit {
    width: 100%;
    margin-top: 10px;
  }
  
  .weight-table {
    font-size: 11px;
  }
  
  .weight-table thead th {
    padding: 8px 4px;
    font-size: 10px;
  }
  
  .weight-table tbody td {
    padding: 6px 4px;
    font-size: 11px;
  }
  
  .engineering-table thead th {
    font-size: 9px;
    padding: 6px 3px;
  }
  
  .engineering-table tbody td {
    font-size: 10px;
    padding: 5px 3px;
  }
  
  .formula-box {
    padding: 15px;
    margin: 15px 0;
  }
  
  .formula-box p {
    font-size: 14px;
  }
  
  .example-box {
    padding: 15px;
    margin: 15px 0;
  }
  
  .example-box p {
    font-size: 13px;
  }
  
  .pipe-table {
    font-size: 10px;
  }
  
  .pipe-table thead th {
    font-size: 9px;
    padding: 6px 3px;
  }
  
  .pipe-table tbody td {
    font-size: 10px;
    padding: 5px 3px;
  }
}