/* ==================== CSS Variables ==================== */
:root {
  --primary-color: #007bff;
  --primary-hover: #0056b3;
  --secondary-color: #f8f9fa;
  --text-color: #333;
  --error-color: red;
  --success-color: green;
  --font-family: 'Arial', sans-serif;
}

/* ==================== Reset / Base ==================== */
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
  font-family: var(--font-family);
}

body {
  color: var(--text-color);
  line-height: 1.6;
  background-color: #fff;
}

/* ==================== Layout ==================== */
.container {
  width: 90%;
  max-width: 600px;
  margin: 0 auto;
}

/* ==================== UI Components ==================== */

/* Buttons */
.btn {
  background-color: var(--primary-color);
  color: #fff;
  border-radius: 5px;
  text-decoration: none;
  transition: all 0.3s ease;
}

.btn:hover {
  background-color: var(--primary-hover);
  transform: translateY(-3px);
  box-shadow: 0 5px 15px rgba(0, 0, 0, 0.2);
}

/* Cards */
.card {
  background-color: #fff;
  padding: 24px;
  border-radius: 12px;
  transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.card:hover {
  transform: translateY(-5px);
  box-shadow: 0 12px 30px rgba(0, 0, 0, 0.15);
}

/* ==================== Header ==================== */
.header {
  background-color: var(--primary-color);
  color: #fff;
  padding: 1rem 0;
}

.header__container {
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.nav__list {
  list-style: none;
  display: flex;
  gap: 1.5rem;
}

.nav__link {
  color: #fff;
  text-decoration: none;
  transition: color 0.3s;
}

.nav__link:hover {
  color: #ffd700;
}

/* ==================== Hero ==================== */
.hero {
  background-color: #e9ecef;
  padding: 6rem 0;
  text-align: center;
}

.hero__title {
  font-size: 2.5rem;
  margin-bottom: 1rem;
}

.hero__subtitle {
  font-size: 1.2rem;
  margin-bottom: 2rem;
}

.hero__btn {
  padding: 0.75rem 2rem;
}

/* ==================== Features ==================== */
.features {
  background-color: var(--secondary-color);
  padding: 4rem 0;
}

.features__container {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: 2rem;
}

.feature {
  text-align: center;
}

.feature__title {
  font-size: 1.5rem;
  margin-bottom: 1rem;
}

/* ==================== Form ==================== */
.form-section {
  padding: 4rem 0;
}

.form-section__container {
  max-width: 400px;
  margin: 0 auto;
}

.form-section__title {
  text-align: center;
  margin-bottom: 2rem;
  font-size: 2rem;
}

.form {
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

.form-group {
  display: flex;
  flex-direction: column;
}

.form input {
  padding: 0.75rem;
  border: 1px solid #ccc;
  border-radius: 5px;
  width: 100%;
  transition: border-color 0.3s, box-shadow 0.3s;
}

.form input:focus {
  border-color: var(--primary-color);
  box-shadow: 0 0 0 3px rgba(0, 123, 255, 0.15);
}

.form input.error {
  border-color: var(--error-color);
  animation: shake 0.3s;
}

.form input.success {
  border-color: var(--success-color);
}

.error-message {
  height: 1rem;
  font-size: 0.85rem;
  color: var(--error-color);
  opacity: 0;
  transition: opacity 0.3s;
}

.error-message.show {
  opacity: 1;
}

.form__btn {
  padding: 0.75rem;
  border: none;
  cursor: pointer;
}

.form__message {
  margin-top: 0.5rem;
  font-weight: bold;
  text-align: center;
  opacity: 0;
  transition: opacity 0.3s ease;
}

.form__message.show {
  opacity: 1;
  animation: fadeIn 0.5s;
}

/* ==================== Footer ==================== */
.footer {
  background-color: #343a40;
  color: #fff;
  padding: 1rem 0;
  text-align: center;
}

/* ==================== Animations ==================== */
.section {
  opacity: 0;
  transform: translateY(40px);
  transition: all 0.6s ease;
}

.section.visible {
  opacity: 1;
  transform: translateY(0);
}

@keyframes shake {
  0% { transform: translateX(0); }
  25% { transform: translateX(-4px); }
  50% { transform: translateX(4px); }
  75% { transform: translateX(-4px); }
  100% { transform: translateX(0); }
}

@keyframes fadeIn {
  from { opacity: 0; }
  to { opacity: 1; }
}

/* ==================== Responsive ==================== */
@media (max-width: 768px) {
  .features__container {
    grid-template-columns: 1fr;
  }

  .hero__title {
    font-size: 2rem;
  }

  .hero__subtitle {
    font-size: 1rem;
  }

  .form-section__container {
    padding: 0 1rem;
  }
}