*{box-sizing:border-box}
:root{font-family:Inter,"Segoe UI",Arial,sans-serif;background:#f4f6f8;color:#17202a}
body{margin:0;min-height:100vh;background:#f4f6f8}
body.modal-open{overflow:hidden}
.container{width:min(1040px,calc(100% - 32px));margin:32px auto 60px}
.hero {width: 100%;margin: 0;padding: 0;overflow: hidden;}
.hero-image {display: block;width: 100%;height: auto;}
.tutorial-space{padding:28px 0 34px}
.tutorial-placeholder{height:270px;border:2px dashed #bfc8cf;border-radius:13px;background:#fafbfc;display:flex;align-items:center;justify-content:center;text-align:center;color:#7a858e}
.placeholder-label{font-weight:700;color:#65717b}
.tutorial-placeholder p,.beam-display-placeholder p,.author-placeholder p{margin:7px 0 0;font-size:14px}
.card{background:white;border:1px solid #dfe4e8;border-radius:14px;padding:26px;margin-bottom:18px;box-shadow:0 3px 12px rgba(20,30,40,.04)}
.section-title{display:flex;gap:14px;align-items:flex-start;margin-bottom:22px}
.step{display:inline-flex;width:30px;height:30px;flex:0 0 30px;align-items:center;justify-content:center;border-radius:50%;background:#17202a;color:white;font-weight:700;font-size:14px}
.section-title h2{margin:0 0 4px;font-size:21px}
.section-title p,.subsection-title p{margin:0;color:#6c7680;font-size:14px}
.span-control{display:flex;align-items:center;justify-content:space-between;max-width:330px;margin-bottom:18px}
.span-control label{font-weight:600}
.counter{display:flex;align-items:center;border:1px solid #cfd6dc;border-radius:8px;overflow:hidden}
.counter button{width:38px;height:36px;border:0;background:#f3f5f7;cursor:pointer;font-size:22px}
.counter button:hover{background:#e8edf1}
.counter span{width:45px;text-align:center;font-weight:600}
.table-wrapper{overflow-x:auto}
table{width:100%;border-collapse:collapse;min-width:600px}
th{background:#f5f7f9;font-weight:600;color:#4f5b66}
th,td{padding:12px 14px;border:1px solid #e1e6ea;text-align:center}
td:first-child{font-weight:600;width:100px}
table input{display:block;width:100%;padding:10px 11px;border:1px solid #cbd3da;border-radius:7px;background:white;font:inherit;color:#17202a;text-align:center}
input:focus,select:focus{outline:none;border-color:#5b6f82;box-shadow:0 0 0 3px rgba(91,111,130,.12)}
.invalid-input{border-color:#c62828!important;box-shadow:0 0 0 2px rgba(198,40,40,.08)}
.generate-area,.calculate-area{text-align:center;margin-top:22px}
.generate-button{min-width:180px;padding:12px 24px;border:0;border-radius:8px;background:#356b4b;color:white;font:inherit;font-weight:700;cursor:pointer}
.generate-button:hover{background:#2c5b40}
.property-name {
  width: 150px;
  font-weight: 500;
  white-space: nowrap;
}
/* Remove increase/decrease arrows only from E and I */

/* Chrome, Edge, Safari */
#elasticModulus::-webkit-inner-spin-button,
#elasticModulus::-webkit-outer-spin-button,
#momentInertia::-webkit-inner-spin-button,
#momentInertia::-webkit-outer-spin-button {
  -webkit-appearance: none;
  margin: 0;
}

/* Firefox */
#elasticModulus,
#momentInertia {
  -moz-appearance: textfield;
  appearance: textfield;
}
.validation-message{min-height:20px;margin:10px 0 0;color:#c62828;font-size:14px;font-weight:600}
.beam-display-placeholder{margin-top:22px;min-height:190px;border:2px dashed #bfc8cf;border-radius:11px;background:#fafbfc;display:flex;flex-direction:column;align-items:center;justify-content:center;text-align:center;color:#7a858e}
#beamImage {
  display: block;
  max-width: 100%;
  height: auto;
  margin: 0 auto;
}

.result-graph-message {
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: center;

  padding: 30px;

  color: #c62828;
  font-weight: 600;
  text-align: center;
  line-height: 1.5;
}

.graph-placeholder{
    position:relative;
    width:100%;
    min-height:360px;
    border:1px solid #dfe4e8;
    border-radius:10px;
    background:#fcfdfd;
    overflow:hidden;
}

.result-graph-image{
    display:block;
    width:100%;
    height:auto;
}

.math-function {
  margin-top: 10px;
  padding: 20px;
  overflow-x: auto;
  border: 1px solid #dfe4e8;
  border-radius: 8px;
  background: #f7f8fa;
  text-align: center;
  font-size: 18px;
}
.function-error-message {
  color: #c62828;
  font-weight: 600;
  text-align: center;
  line-height: 1.5;
}

.mode-grid{display:grid;grid-template-columns:repeat(2,1fr);gap:14px}
.mode-card{min-height:70px;display:flex;align-items:center;justify-content:center;text-align:center;padding:17px;border:1px solid #cfd6dc;border-radius:10px;background:white;cursor:pointer;font:inherit;font-weight:700}
.mode-card:hover{border-color:#7b8995;background:#fafbfc}
.mode-card.active{border-color:#17202a;box-shadow:inset 0 0 0 1px #17202a;background:#f7f9fa}
.options-panel{margin-top:22px;padding:20px;border:1px solid #e1e6ea;border-radius:10px;background:#fafbfc}
.option-group{margin-bottom:18px}.option-group:last-child{margin-bottom:0}
.option-group>label{display:block;font-weight:600;margin-bottom:10px}
.radio-group{display:flex;flex-wrap:wrap;gap:10px}
.radio-option{display:inline-flex;align-items:center;gap:8px;padding:9px 12px;border:1px solid #d0d7dd;border-radius:8px;background:white;cursor:pointer}
.radio-option:has(input:checked){border-color:#17202a;background:#f2f5f7}
.radio-option input{width:auto;margin:0}
.inline-input,.material-row{display:flex;align-items:center;gap:8px;max-width:420px}
.inline-input .prefix,.load-input-row .prefix,.material-row .prefix{font-weight:600;white-space:nowrap}
.inline-input input,.material-row input{width:180px;padding:10px 11px;border:1px solid #cbd3da;border-radius:7px;font:inherit;text-align:center}
.inline-input .unit,.material-row .unit{height:40px;display:flex;align-items:center;padding:0 11px;border:1px solid #cbd3da;border-radius:7px;background:#f3f5f7;color:#5e6973}
.material-inputs{display:grid;gap:12px;margin-top:12px}
.load-input-row{display:flex;align-items:center;gap:10px;max-width:390px}
.load-input-row input{width:170px;padding:10px 11px;border:1px solid #cbd3da;border-radius:7px;font:inherit;text-align:center}
.load-input-row select{height:40px;padding:0 10px;border:1px solid #cbd3da;border-radius:7px;background:white;font:inherit;color:#17202a}
.calculate-button{width:100%;max-width:280px;padding:13px 22px;border:0;border-radius:8px;background:#17202a;color:white;font:inherit;font-weight:700;cursor:pointer}
.calculate-button:hover{background:#303c47}

.graph-placeholder svg{position:absolute;inset:30px;width:calc(100% - 60px);height:calc(100% - 60px)}
.axis-line{stroke:#8b969f;stroke-width:1.5}.graph-line{fill:none;stroke:#17202a;stroke-width:3}
.axis-y,.axis-x{position:absolute;font-size:13px;color:#65717c;z-index:2}
.axis-y{top:12px;left:20px}.axis-x{right:15px;bottom:9px}
.placeholder-text{position:absolute;left:50%;bottom:13px;transform:translateX(-50%);color:#8a949d;font-size:12px;white-space:nowrap}
.evaluation-panel,.function-panel{margin-top:22px;padding-top:22px;border-top:1px solid #e5e9ec}
.subsection-title h3{margin:0 0 5px;font-size:17px}
.evaluate-row{display:flex;align-items:center;gap:10px;margin-top:16px}
.evaluate-row>label{font-weight:600;white-space:nowrap}
.input-with-unit{display:flex;align-items:center;width:180px}
.input-with-unit input{width:100%;padding:10px 11px;border:1px solid #cbd3da;border-radius:7px 0 0 7px;font:inherit;text-align:center}
.input-with-unit span{height:40px;display:flex;align-items:center;padding:0 11px;border:1px solid #cbd3da;border-left:0;border-radius:0 7px 7px 0;background:#f3f5f7;color:#5e6973}
.secondary-button,.function-toggle{padding:10px 15px;border:1px solid #c4ccd3;border-radius:7px;background:white;color:#17202a;font:inherit;font-weight:600;cursor:pointer}
.secondary-button:hover,.function-toggle:hover{background:#f3f5f7}
.evaluation-result{margin-top:14px;padding:13px 15px;border-radius:8px;background:#f3f6f8;font-size:15px}
.function-content{margin-top:16px}.function-content h3{font-size:17px;margin-bottom:10px}
pre{margin:0;padding:16px;overflow-x:auto;border:1px solid #dfe4e8;border-radius:8px;background:#f7f8fa;font-family:"Cambria Math","Times New Roman",serif;line-height:1.65}
.author-section{padding:20px 0 6px}
.author-card{padding:30px 24px 22px;border-top:1px solid #dfe4e8;text-align:center}
.author-card h2{margin:0 0 5px;font-size:22px;color:#17202a}
.author-role{margin:0;font-size:15px;font-weight:600;color:#3f4a54}
.author-specialization{margin:4px 0 0;font-size:14px;color:#6c7680}
.author-links{display:flex;justify-content:center;align-items:center;gap:22px;margin:20px 0 16px}
.author-link{display:inline-flex;align-items:center;gap:8px;color:#17202a;text-decoration:none;font-size:14px;font-weight:600;transition:color .18s ease,transform .18s ease}
.author-link:hover{color:#356b4b;transform:translateY(-1px)}
.author-link svg{width:19px;height:19px;fill:currentColor}
.author-feedback{max-width:650px;margin:0 auto;color:#5e6973;font-size:14px;line-height:1.6}
.copyright{margin:22px 0 0;padding-top:16px;border-top:1px solid #e5e9ec;color:#7a858e;font-size:12px}

.disclaimer-overlay{position:fixed;inset:0;z-index:1000;display:flex;align-items:center;justify-content:center;padding:20px;background:rgba(11,18,24,.72);backdrop-filter:blur(3px)}
.disclaimer-modal{width:min(850px,100%);max-height:min(850px,calc(100vh - 40px));overflow-y:auto;padding:32px 34px 28px;border-radius:15px;background:white;box-shadow:0 18px 60px rgba(0,0,0,.30)}
.disclaimer-modal h2{margin:0 0 20px;font-size:26px}.disclaimer-modal p{margin:0 0 15px;color:#3f4a54;font-size:14px;line-height:1.65}
.agree-button{display:block;margin:24px auto 0;min-width:190px;padding:12px 24px;border:0;border-radius:8px;background:#398052;color:white;font:inherit;font-weight:700;cursor:pointer}
.agree-button:hover{background:#306d45}.hidden{display:none!important}
@media(max-width:700px){.container{width:min(100% - 20px,1040px);margin-top:20px}.tutorial-placeholder{height:220px}.card{padding:19px}.mode-grid{grid-template-columns:1fr}.evaluate-row,.load-input-row,.inline-input,.material-row{align-items:stretch;flex-direction:column}.input-with-unit,.load-input-row input,.load-input-row select,.inline-input input,.material-row input{width:100%;max-width:none}.secondary-button{width:100%}.placeholder-text{font-size:10px}.disclaimer-modal{padding:25px 22px 22px}}


/* Calculation progress indicator */
.calculate-button.calculating,
.calculate-button:disabled,
.generate-button.calculating,
.generate-button:disabled {
  cursor: wait;
  opacity: .82;
}

.calculate-button.calculating,
.generate-button.calculating {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
}

.calculation-spinner {
  width: 17px;
  height: 17px;
  flex: 0 0 17px;
  border: 2px solid rgba(255,255,255,.38);
  border-top-color: #fff;
  border-radius: 50%;
  animation: calculation-spin .75s linear infinite;
}

@keyframes calculation-spin {
  to { transform: rotate(360deg); }
}

/* Hypotheses */
.hypothesis-list{
  display:grid;
  gap:14px;
}

.hypothesis-item{
  display:grid;
  grid-template-columns:48px 1fr;
  gap:14px;
  padding:16px 18px;
  border:1px solid #e1e6ea;
  border-radius:10px;
  background:#fafbfc;
}

.hypothesis-number{
  font-weight:700;
  color:#17202a;
  line-height:1.5;
}

.hypothesis-content h3{
  margin:0 0 6px;
  font-size:16px;
  color:#17202a;
}

.hypothesis-content p{
  margin:0;
  color:#4f5b66;
  font-size:14px;
  line-height:1.65;
}

@media(max-width:700px){
  .hypothesis-item{
    grid-template-columns:36px 1fr;
    gap:10px;
    padding:14px;
  }
}


@media(max-width:700px){
  .author-card{padding:25px 16px 18px}
  .author-links{gap:18px}
  .author-feedback{font-size:13px}
}