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

body {
  font-family: "Inter", -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto,
    sans-serif;
  background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 20px;
  position: relative;
  overflow-x: hidden;
}

body::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: url('data:image/svg+xml,<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 100 100"><defs><pattern id="grain" width="100" height="100" patternUnits="userSpaceOnUse"><circle cx="50" cy="50" r="1" fill="white" opacity="0.1"/></pattern></defs><rect width="100" height="100" fill="url(%23grain)"/></svg>');
  pointer-events: none;
  z-index: 1;
}

.container {
  background: rgba(255, 255, 255, 0.1);
  backdrop-filter: blur(20px);
  border: 1px solid rgba(255, 255, 255, 0.2);
  border-radius: 24px;
  padding: 48px;
  text-align: center;
  width: 100%;
  max-width: 480px;
  box-shadow: 0 8px 32px rgba(0, 0, 0, 0.1), 0 0 0 1px rgba(255, 255, 255, 0.1);
  position: relative;
  z-index: 2;
  animation: fadeInUp 0.6s ease-out;
}

@keyframes fadeInUp {
  from {
    opacity: 0;
    transform: translateY(30px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.container::before {
  content: "";
  position: absolute;
  top: -2px;
  left: -2px;
  right: -2px;
  bottom: -2px;
  background: linear-gradient(45deg, #ff6b6b, #4ecdc4, #45b7d1, #96ceb4);
  border-radius: 26px;
  z-index: -1;
  opacity: 0.3;
  animation: borderGlow 3s ease-in-out infinite alternate;
}

@keyframes borderGlow {
  0% {
    opacity: 0.3;
  }
  100% {
    opacity: 0.6;
  }
}

/* Header Styles */
header {
  margin-bottom: 32px;
}

h1 {
  font-size: 2.5rem;
  font-weight: 700;
  color: rgba(255, 255, 255, 0.95);
  text-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
  letter-spacing: -0.025em;
  margin-bottom: 8px;
  background: linear-gradient(135deg, #ffffff 0%, #e0e7ff 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.subtitle {
  font-size: 1rem;
  color: rgba(255, 255, 255, 0.7);
  font-weight: 400;
  letter-spacing: 0.025em;
}

/* Form Styles */
form {
  margin-bottom: 24px;
}

.input-group {
  margin-bottom: 32px;
}

label {
  font-size: 1.25rem;
  font-weight: 600;
  margin-bottom: 16px;
  display: block;
  color: rgba(255, 255, 255, 0.95);
  text-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
  letter-spacing: -0.025em;
}

input[type="date"] {
  width: 100%;
  padding: 16px 20px;
  border: 2px solid rgba(255, 255, 255, 0.2);
  border-radius: 12px;
  margin-bottom: 8px;
  font-size: 1rem;
  background: rgba(255, 255, 255, 0.1);
  color: white;
  backdrop-filter: blur(10px);
  transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  font-family: inherit;
}

input[type="date"]:focus {
  outline: none;
  border-color: rgba(255, 255, 255, 0.8);
  box-shadow: 0 0 0 4px rgba(255, 255, 255, 0.1);
  transform: translateY(-2px);
}

input[type="date"]::-webkit-calendar-picker-indicator {
  filter: invert(1);
  cursor: pointer;
  opacity: 0.7;
  transition: opacity 0.3s ease;
}

input[type="date"]::-webkit-calendar-picker-indicator:hover {
  opacity: 1;
}

small {
  display: block;
  font-size: 0.875rem;
  color: rgba(255, 255, 255, 0.6);
  font-weight: 400;
  text-align: left;
  margin-top: 4px;
}

.button-group {
  display: flex;
  gap: 12px;
  justify-content: center;
  flex-wrap: wrap;
}

button {
  padding: 14px 28px;
  border: none;
  border-radius: 12px;
  font-size: 1rem;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  font-family: inherit;
  position: relative;
  overflow: hidden;
  letter-spacing: -0.025em;
  min-width: 140px;
}

button::before {
  content: "";
  position: absolute;
  top: 0;
  left: -100%;
  width: 100%;
  height: 100%;
  background: linear-gradient(
    90deg,
    transparent,
    rgba(255, 255, 255, 0.2),
    transparent
  );
  transition: left 0.5s;
}

button:hover::before {
  left: 100%;
}

button:active {
  transform: scale(0.98);
}

.primary-btn {
  background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
  color: white;
  box-shadow: 0 4px 15px rgba(102, 126, 234, 0.4);
}

.primary-btn:hover {
  box-shadow: 0 6px 20px rgba(102, 126, 234, 0.6);
  transform: translateY(-2px);
}

.reset-btn {
  background: linear-gradient(135deg, #ff6b6b 0%, #ee5a52 100%);
  color: white;
  box-shadow: 0 4px 15px rgba(255, 107, 107, 0.4);
}

.reset-btn:hover {
  box-shadow: 0 6px 20px rgba(255, 107, 107, 0.6);
  transform: translateY(-2px);
}

#result {
  margin-top: 24px;
  padding: 20px;
  border-radius: 16px;
  font-size: 1.1rem;
  font-weight: 500;
  line-height: 1.6;
  background: rgba(255, 255, 255, 0.1);
  backdrop-filter: blur(10px);
  border: 1px solid rgba(255, 255, 255, 0.2);
  color: rgba(255, 255, 255, 0.95);
  text-shadow: 0 1px 2px rgba(0, 0, 0, 0.1);
  animation: slideIn 0.4s ease-out;
  min-height: 60px;
  display: flex;
  align-items: center;
  justify-content: center;
}

@keyframes slideIn {
  from {
    opacity: 0;
    transform: translateY(10px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

/* Success state */
#result[style*="green"] {
  background: rgba(34, 197, 94, 0.2);
  border-color: rgba(34, 197, 94, 0.3);
  color: #22c55e;
}

/* Error state */
#result[style*="red"] {
  background: rgba(239, 68, 68, 0.2);
  border-color: rgba(239, 68, 68, 0.3);
  color: #ef4444;
}

/* Footer Styles */
.footer {
  position: fixed;
  bottom: 0;
  left: 0;
  right: 0;
  padding: 20px;
  z-index: 10;
  animation: fadeInUp 0.8s ease-out 0.3s both;
}

.footer-content {
  display: flex;
  justify-content: space-between;
  align-items: center;
  max-width: 480px;
  margin: 0 auto;
  background: rgba(255, 255, 255, 0.1);
  backdrop-filter: blur(20px);
  border: 1px solid rgba(255, 255, 255, 0.2);
  border-radius: 16px;
  padding: 16px 24px;
  box-shadow: 0 4px 20px rgba(0, 0, 0, 0.1);
}

.footer-text {
  font-size: 0.9rem;
  color: rgba(255, 255, 255, 0.8);
  font-weight: 500;
  margin: 0;
}

.author-name {
  font-weight: 700;
  color: rgba(255, 255, 255, 0.95);
  background: linear-gradient(135deg, #ff6b6b 0%, #4ecdc4 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  text-shadow: 0 1px 2px rgba(0, 0, 0, 0.1);
}

.social-links {
  display: flex;
  gap: 12px;
  align-items: center;
}

.social-link {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 36px;
  height: 36px;
  border-radius: 50%;
  background: rgba(255, 255, 255, 0.1);
  border: 1px solid rgba(255, 255, 255, 0.2);
  color: rgba(255, 255, 255, 0.8);
  text-decoration: none;
  transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  backdrop-filter: blur(10px);
}

.social-link:hover {
  background: rgba(255, 255, 255, 0.2);
  color: rgba(255, 255, 255, 1);
  transform: translateY(-2px);
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.2);
}

.social-link:active {
  transform: scale(0.95);
}

/* Responsive Design */
@media (max-width: 640px) {
  .container {
    padding: 32px 24px;
    margin: 16px;
  }

  h1 {
    font-size: 2rem;
  }

  label {
    font-size: 1.1rem;
  }

  input[type="date"] {
    padding: 14px 16px;
    font-size: 0.95rem;
  }

  button {
    padding: 12px 20px;
    font-size: 0.95rem;
    min-width: 120px;
  }

  #result {
    font-size: 1rem;
    padding: 16px;
  }

  .button-group {
    flex-direction: column;
    align-items: center;
  }

  .footer {
    padding: 16px;
  }

  .footer-content {
    flex-direction: column;
    gap: 12px;
    text-align: center;
    padding: 16px 20px;
  }

  .footer-text {
    font-size: 0.85rem;
  }

  .social-links {
    gap: 8px;
  }

  .social-link {
    width: 32px;
    height: 32px;
  }
}

@media (max-width: 480px) {
  body {
    padding: 16px;
  }

  .container {
    padding: 24px 20px;
  }

  h1 {
    font-size: 1.75rem;
  }

  label {
    font-size: 1rem;
  }

  input[type="date"] {
    padding: 12px 14px;
    font-size: 0.9rem;
  }

  button {
    padding: 10px 16px;
    font-size: 0.9rem;
    min-width: 100px;
  }

  .footer-content {
    padding: 12px 16px;
  }

  .footer-text {
    font-size: 0.8rem;
  }

  .social-link {
    width: 28px;
    height: 28px;
  }
}

/* Loading animation for better UX */
.loading {
  opacity: 0.7;
  pointer-events: none;
}

/* Focus styles for accessibility */
button:focus,
input[type="date"]:focus,
.social-link:focus {
  outline: 2px solid rgba(255, 255, 255, 0.8);
  outline-offset: 2px;
}

/* Smooth scrolling */
html {
  scroll-behavior: smooth;
}