body {
  background: #ff3131;
  margin: 0;
  font-family: 'Montserrat', Arial, sans-serif;
}

.container {
  text-align: center;
  padding: 40px 0;
}

h1 {
  font-size: 4em;
  margin-bottom: 0;
  font-weight: 900;
}

.bold {
  font-weight: 900;
}

.subtitle {
  margin-top: 5px;
  margin-bottom: 40px;
  font-size: 1.2em;
}

.button-grid {
  display: flex;
  justify-content: center;
  gap: 40px;
  margin-top: 40px;
  flex-wrap: wrap;
}

.convert-btn, .nav-btn {
  background: #db0000;
  color: white;
  font-size: 1.4em;
  font-weight: bold;
  padding: 40px 50px;
  border: none;
  border-radius: 25px;
  cursor: pointer;
  box-shadow: 0 4px 14px rgba(0,0,0,0.12);
  transition: transform 0.1s, background 0.2s;
  margin-bottom: 20px;
}

.convert-btn:hover,
.nav-btn.active,
.nav-btn:hover {
  background: #f98181;
  color: #a93226;
  border: 2px solid #a93226;
  transform: scale(1.05);
}

.header {
  background: #db0000;
  padding: 20px 0 10px 0;
  border-radius: 8px;
  margin: 20px 16px 0 16px;
  box-shadow: 0 4px 16px rgba(0,0,0,0.4);
  text-align: center;
}

.header h2 {
  color: #fff;
  font-size: 2rem;
  font-weight: 800;
  letter-spacing: 1px;
  margin: 0;
}

.conversion-nav {
  display: flex;
  justify-content: center;
  gap: 32px;
  margin: 38px 0 32px 0;
  flex-wrap: wrap;
}

.nav-btn {
  font-size: 1.2em;
  font-weight: bold;
  padding: 16px 40px;
  border-radius: 10px;
  box-shadow: 0 2px 6px rgba(0,0,0,0.09);
}

.conversion-card {
  background: #db0000;
  padding: 32px 24px;
  border-radius: 30px;
  margin: 40px auto 0 auto;
  width: 350px;
  color: white;
  box-shadow: 0 6px 24px rgba(0,0,0,0.12);
  text-align: center;
  display: flex;
  flex-direction: column;
  gap: 28px;
}

.input-row {
  display: flex;
  justify-content: center;
  align-items: center;
  gap: 10px;
}

.input-box {
  width: 60px;
  font-size: 1.5rem;
  padding: 12px 6px;
  border: none;
  border-radius: 8px;
  background: #f98181;
  color: #a93226;
  text-align: center;
  font-weight: bold;
  outline: none;
  text-wrap: balance;
}

.unit-label {
  font-size: 1.2em;
  font-weight: bold;
  margin: 0 3px;
}

.equals-row {
  display: flex;
  justify-content: center;
}

.equals-btn {
  width: 54px;
  height: 54px;
  border-radius: 50%;
  background: #f98181;
  color: #a93226;
  border: none;
  font-size: 2em;
  font-weight: bold;
  cursor: pointer;
  box-shadow: 0 4px 14px rgba(0,0,0,0.13);
  transition: background 0.1s;
}
.equals-btn:hover {
  background: #c96157;
}

.output-row {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 12px;
  background: #f98181;
  padding: 20px 6px;
  border-radius: 12px;
  min-height: 62px;
}

.output-value {
  background: none;
  border: none;
  font-size: 2em;
  color: #a93226;
  font-weight: bold;
  min-width: 48px;
  text-align: right;
}

.output-unit {
  background: #db0000;
  color: white;
  border-radius: 8px;
  padding: 6px 12px;
  font-size: 1.2em;
  font-weight: bold;
}

#ft-cm-card,
#yard-ft-card,
#mi-km-card,
#km-nmi-card,
#kg-pound-card,
#g-oz-card,
#lb-oz-card,
#st-lb-card,
#t-kg-card,
#l-gal-card,
#l-ccm-card,
#cci-ml-card,
#pt-l-card,
#oz-ml-card {
  display: none;
}

/* Dropdown (select) styles for currency card */
.input-row select {
  appearance: none;
  -webkit-appearance: none;
  -moz-appearance: none;
  background: #f89b9b;
  color: #a93226;
  border: none;
  border-radius: 8px;
  padding: 12px 32px 12px 12px;
  margin: 0 6px;
  font-size: 1.1em;
  font-family: inherit;
  font-weight: bold;
  outline: none;
  box-shadow: 0 2px 7px rgba(0,0,0,0.11);
  transition: background 0.15s, color 0.15s;
  cursor: pointer;
}

.input-row select:focus {
  border: 2px solid #a93226;
  background: #ffe0e0;
}

.input-row select option {
  background: #fff;
  color: #a93226;
  font-weight: 500;
}

/* Responsive polish */
@media (max-width: 520px) {
  .button-grid {
    flex-direction: column;
    gap: 22px;
  }
  .container {
    padding: 20px 0;
  }
  .conversion-card {
    width: 98vw;
    min-width: 0;
    padding: 18px 4px;
    margin-top: 24px;
    border-radius: 14px;
  }
  .conversion-nav {
    flex-direction: column;
    gap: 17px;
    margin: 20px 0 20px 0;
  }
  .convert-btn, .nav-btn {
    padding: 20px 10px;
    font-size: 1em;
    border-radius: 13px;
  }
}

@media (max-width:350px) {
  h1 {
    font-size: 2.3em;
  }
  .conversion-card {
    font-size: 0.9em;
  }
}