@font-face {
    font-family: "IRANSANS";
    src: url("font-awesome/IRANSansWeb.woff") format("woff"),
         url("font-awesome/IRANSansWeb.ttf") format("truetype");
    font-weight: normal;
    font-style: normal;
  }
  
  body {
    font-family: 'IRANSANS';
    background-color: #f9f9f9;
    margin: 0;
    padding: 0;
  }
  
  /* ✅ فیلد ورودی عدد */
  #inputs {
    height: 60px;
    font-size: 24px;
    padding: 10px 15px;
    border-radius: 8px;
    text-align: center;
    font-family: 'IRANSANS';
    border: 1px solid #ced4da;
    background-color: #fff;
    width: 100%;
    box-sizing: border-box;
    margin-bottom: 20px;
  }
  
  /* ✅ نسخه واکنش‌گرا برای موبایل */
  @media only screen and (max-width: 768px) {
    #inputs {
      height: 80px;
      font-size: 28px;
    }
  }
  
  /* ✅ منوی انتخاب سال */
  .form-select {
    margin-bottom: 20px;
    text-align: center;
    display: block;
    width: 100%;
    padding: .375rem 2.25rem .375rem .75rem;
    -moz-padding-start: calc(0.75rem - 3px);
    font-size: 1.4rem;
    font-weight: 400;
    color: #212529;
    background-color: #fff;
    background-image: url(download.svg);
    background-repeat: no-repeat;
    background-position: right .75rem center;
    background-size: 16px 12px;
    border: 1px solid #ced4da;
    border-radius: 4px;
    transition: border-color .15s ease-in-out, box-shadow .15s ease-in-out;
    -webkit-appearance: none;
    -moz-appearance: none;
    appearance: none;
    height: 3.125rem;
  }
  
  /* ✅ دکمه چرخشی */
  .rotate-button {
    display: inline-block;
    width: 150px;
    height: 30px;
    text-align: center;
    transform-style: preserve-3d;
    cursor: pointer;
    transition: all .5s ease;
    font-family: 'arial';
    position: relative;
  }
  
  .rotate-button .rotate-button-face,
  .rotate-button .rotate-button-face-back {
    position: absolute;
    display: block;
    border: 1px solid #35495e;
    transition: all .8s;
    color: #35495e;
    text-decoration: none;
    width: 150px;
    height: 30px;
    line-height: 30px;
    border-radius: 4px;
  }
  
  .rotate-button .rotate-button-face {
    background-color: #013183;
    transform: translateZ(15px);
    color: #fff;
    border: 1px solid #fff;
  }
  
  .rotate-button .rotate-button-face-back {
    background-color: #35495e;
    color: #42b883;
    border: 1px solid #42b883;
    transform: rotateX(-90deg) translateZ(15px);
  }
  
  .rotate-button:hover {
    transform: rotateX(90deg);
  }
  
  /* ✅ بخش هدر */
  #headers {
    border: 3px solid grey;
    margin-top: 20px;
    border-radius: 6px;
    padding: 10px;
    width: 50%;
    margin: auto;
    font-family: 'IRANSANS';
  }
  
  /* ✅ دکمه اصلی */
  .button {
    width: 100% !important;
    display: block !important;
    margin: auto !important;
    font-family: IRANSANS !important;
  }
  
  /* ✅ دکمه‌های گرادیانی */
  .btn-hover {
    width: 200px;
    font-size: 13px;
    font-weight: 600;
    color: #fff;
    cursor: pointer;
    margin: 10px;
    height: 55px;
    text-align: center;
    font-family: iransansnum !important;
    background-size: 300% 100%;
    border-radius: 50px;
    transition: all .4s ease-in-out;
  }
  
  .btn-hover:hover {
    background-position: 100% 0;
  }
  
  .btn-hover:focus {
    outline: none;
  }
  
  .btn-hover.color-1 {
    background-image: linear-gradient(to right, #aa0523, #a19ca0, #4ec8ed, #8f9194, #7f7f7f);
  }
  
  .btn-hover.color-2 {
    background-image: linear-gradient(to right, #842066, #1c4690, #4ec8ed, #1c4690, #842066);
    box-shadow: 0 4px 15px 0 #00b0f0;
  }
  
  .btn-hover.color-3 {
    background-image: linear-gradient(to right, #842066, #1c4690, #4ec8ed, #1c4690, #842066);
    box-shadow: 0 4px 15px 0 #00b050;
  }