:root {
  /* Colors */
  --clr-primary-500: hsl(223, 87%, 63%);
  --clr-secondary-200: hsl(223, 100%, 88%);
  --clr-secondary-400: hsl(354, 100%, 66%);
  --clr-neutral-400: hsl(0, 0%, 59%);
  --clr-neutral-950: hsl(209, 33%, 12%);
  --clr-white: hsl(0, 0%, 100%);

  /* Typography */
  --ff-primary: 'Libre Franklin', sans-serif;
  --fs-body: 1.25rem; /* 20px base */

  /* Spacing Guidelines via Fluid Clamp functions */
  --space-sm: clamp(1rem, 2vw, 1.5rem);
  --space-md: clamp(2rem, 4vw, 3rem);
  --space-lg: clamp(3.5rem, 6vw, 5rem);
}

*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

body {
  font-family: var(--ff-primary);
  font-size: var(--fs-body);
  color: var(--clr-neutral-950);
  background-color: var(--clr-white);
  min-height: 100vh;
  line-height: 1.5;
  -webkit-font-smoothing: antialiased;
}

img {
  max-width: 100%;
  height: auto;
  display: block;
}

input, button {
  font: inherit;
}

.page-wrapper {
  display: flex;
  flex-direction: column;
  align-items: center;
  max-width: 1440px;
  margin-inline: auto;
  padding-block: var(--space-lg);
  padding-inline: clamp(1.5rem, 5vw, 4rem);
  min-height: 100vh;
}

.header {
  margin-block-end: clamp(2rem, 5vw, 3.5rem);
}

.hero-section {
  text-align: center;
  max-width: 45rem;
  width: 100%;
}

.hero-section__title {
  font-size: clamp(1.75rem, 4vw, 3rem);
  font-weight: 300;
  color: var(--clr-neutral-400);
  margin-block-end: 1rem;
}

.hero-section__title--bold {
  font-weight: 700;
  color: var(--clr-neutral-950);
}

.hero-section__subtitle {
  font-size: clamp(0.9rem, 2vw, 1.15rem);
  font-weight: 300;
  color: var(--clr-neutral-950);
  margin-block-end: 2.5rem;
}

/* Form Styles via BEM pattern */
.notify-form {
  display: flex;
  flex-direction: column;
  gap: 1.25rem;
  width: 100%;
  max-width: 40rem;
  margin-inline: auto;
  margin-block-end: var(--space-lg);
}

.notify-form__input-group {
  position: relative;
  width: 100%;
}

.notify-form__input {
  width: 100%;
  padding-block: 1.1rem;
  padding-inline: 2rem;
  border: 1px solid var(--clr-secondary-200);
  border-radius: 2rem;
  font-size: 0.95rem;
  color: var(--clr-neutral-950);
  outline: none;
  transition: border-color 0.25s ease;
}

.notify-form__input::placeholder {
  color: var(--clr-secondary-200);
}

.notify-form__input:focus {
  border-color: var(--clr-neutral-400);
}

.notify-form__input--error {
  border-color: var(--clr-secondary-400);
}

.notify-form__error {
  color: var(--clr-secondary-400);
  font-size: 0.75rem;
  font-style: italic;
  text-align: left;
  padding-inline-start: 2rem;
  margin-block-start: 0.5rem;
  display: none;
}

/* Error layout state toggled by script */
.notify-form__input-group--invalid .notify-form__error {
  display: block;
}

.notify-form__btn {
  background-color: var(--clr-primary-500);
  color: var(--clr-white);
  font-weight: 600;
  padding-block: 1.1rem;
  padding-inline: 3rem;
  border: none;
  border-radius: 2rem;
  cursor: pointer;
  box-shadow: 0 5px 15px rgba(79, 123, 252, 0.25);
  transition: opacity 0.25s ease, background-color 0.25s ease;
}

.notify-form__btn:hover,
.notify-form__btn:focus-visible {
  opacity: 0.85;
  outline: 2px solid var(--clr-neutral-950);
  outline-offset: 3px;
}

/* Presentation Dashboard Image Area */
.dashboard-preview {
  width: 100%;
  max-width: 40rem;
  margin-block-end: var(--space-lg);
}

.dashboard-preview__img {
  width: 100%;
  height: auto;
}

/* Footer & Interaction Links Area */
.footer {
  margin-block-start: auto;
  text-align: center;
}

.footer__socials {
  display: flex;
  justify-content: center;
  gap: 0.75rem;
  margin-block-end: 2rem;
}

.footer__social-link {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 2.25rem;
  height: 2.25rem;
  border: 1px solid rgba(79, 123, 252, 0.15);
  border-radius: 50%;
  color: var(--clr-primary-500);
  text-decoration: none;
  font-size: 0.9rem;
  transition: background-color 0.25s cubic-bezier(0.4, 0, 0.2, 1), color 0.25s ease;
}

.footer__social-link:hover,
.footer__social-link:focus-visible {
  background-color: var(--clr-primary-500);
  color: var(--clr-white);
  outline: none;
}

.footer__copyright {
  font-size: 0.75rem;
  color: var(--clr-neutral-400);
}

.attribution {
  font-size: 0.7rem;
  text-align: center;
  margin-block-start: 1.5rem;
  color: var(--clr-neutral-400);
}

.attribution a {
  color: var(--clr-primary-500);
  text-decoration: none;
  font-weight: 600;
}

.attribution a:hover {
  text-decoration: underline;
}

@media (min-width: 768px) {
  .notify-form {
    flex-direction: row;
    align-items: flex-start;
    gap: 1rem;
    max-width: 44rem;
  }

  .notify-form__input-group {
    flex: 1;
  }

  .notify-form__error {
    position: absolute;
    left: 0;
    bottom: -1.5rem;
    margin-block-start: 0;
  }

  .notify-form__btn {
    width: auto;
    padding-inline: 4rem;
  }

  .dashboard-preview {
    max-width: 55rem;
  }
}