/* ===== Reset & Base ===== */
*,
*::before,
*::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

:root {
  /* Primary */
  --purple: hsl(259, 100%, 65%);
  --red: hsl(0, 100%, 67%);

  /* Neutral */
  --white: hsl(0, 100%, 100%);
  --grey-100: hsl(0, 0%, 94%);
  --grey-200: hsl(0, 0%, 86%);
  --grey-500: hsl(0, 1%, 44%);
  --black: hsl(0, 0%, 0%);

  /* Typography */
  --font-family: 'Poppins', sans-serif;
  --input-font-size: 32px;
}

body {
  font-family: var(--font-family);
  background-color: var(--grey-100);
  display: flex;
  justify-content: center;
  align-items: center;
  min-height: 100vh;
  padding: 1rem;
}

/* ===== Calculator Card ===== */
.calculator {
  background-color: var(--white);
  border-radius: 1.5rem 1.5rem 6rem 1.5rem;
  padding: 3rem 1.5rem;
  max-width: 840px;
  width: 100%;
  box-shadow: 0 4px 20px rgba(0, 0, 0, 0.05);
}

/* ===== Form ===== */
.inputs {
  display: flex;
  gap: 1rem;
  margin-bottom: 2rem;
}

.input-group {
  display: flex;
  flex-direction: column;
  flex: 1;
}

.input-group label {
  font-size: 0.75rem;
  font-weight: 700;
  letter-spacing: 0.2em;
  color: var(--grey-500);
  margin-bottom: 0.25rem;
  text-transform: uppercase;
}

.input-group input {
  font-family: var(--font-family);
  font-size: var(--input-font-size);
  font-weight: 700;
  padding: 0.75rem 1rem;
  border: 1px solid var(--grey-200);
  border-radius: 0.5rem;
  outline: none;
  transition: border-color 0.2s;
  width: 100%;
}

.input-group input:focus {
  border-color: var(--purple);
}

/* Error states */
.input-group.error label {
  color: var(--red);
}

.input-group.error input {
  border-color: var(--red);
}

.error-message {
  font-size: 0.7rem;
  font-style: italic;
  color: var(--red);
  margin-top: 0.25rem;
  min-height: 1.2em;
}

/* ===== Submit Button & Divider ===== */
.submit-wrapper {
  position: relative;
  display: flex;
  align-items: center;
  margin: 2rem 0;
}

.divider {
  flex: 1;
  height: 1px;
  background-color: var(--grey-200);
}

.submit-btn {
  background-color: var(--purple);
  border: none;
  border-radius: 50%;
  width: 64px;
  height: 64px;
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  transition: background-color 0.2s;
  flex-shrink: 0;
  margin-left: 1rem;
}

.submit-btn:hover,
.submit-btn:focus-visible {
  background-color: var(--black);
}

.submit-btn svg {
  width: 46px;
  height: 44px;
}

/* ===== Result ===== */
.result {
  font-size: 3.5rem;
  font-weight: 800;
  font-style: italic;
  line-height: 1.1;
}

.result p {
  margin: 0;
}

.number {
  color: var(--purple);
  margin-right: 0.5rem;
}

/* ===== Responsive ===== */
@media (max-width: 600px) {
  .calculator {
    padding: 2rem 1rem;
    border-radius: 1.5rem 1.5rem 4rem 1.5rem;
  }

  .inputs {
    gap: 0.75rem;
  }

  .input-group input {
    font-size: 1.25rem;
    padding: 0.5rem 0.75rem;
  }

  .submit-wrapper {
    margin: 1.5rem 0;
  }

  .submit-btn {
    width: 56px;
    height: 56px;
  }

  .result {
    font-size: 2.5rem;
  }
}

@media (min-width: 768px) {
  .calculator {
    padding: 3.5rem 3rem;
  }

  .submit-btn {
    position: absolute;
    right: 0;
    margin-left: 0;
  }

  .divider {
    width: 100%;
  }
}