* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
  font-family: 'Poppins', sans-serif;
  transition: background 0.3s, color 0.3s;
}

body {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  background: var(--bg);
  color: var(--text);
  padding: 5vw; /* responsive padding */
  text-align: center;
}

/* Light & Dark Mode Variables */
:root {
  --bg: linear-gradient(135deg, #ffecd2 0%, #fcb69f 100%);
  --text: #222;
}
body.dark {
  --bg: linear-gradient(135deg, #0f172a 0%, #1e293b 100%);
  --text: #f1f5f9;
}

/* Title + Subtitle */
h1 {
  font-size: clamp(1.8rem, 5vw, 2.5rem); /* responsive scaling */
  font-weight: 600;
  margin-bottom: 1vh;
}
p.subtitle {
  font-size: clamp(1rem, 3.5vw, 1.2rem);
  font-weight: 400;
  margin-bottom: 5vh;
  opacity: 0.9;
}

/* Layout */
ul {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 5vh;
  align-items: center;
}

.icon-content {
  position: relative;
  display: flex;
  justify-content: center;
  align-items: center;
}

/* Tooltip */
.tooltip {
  position: absolute;
  top: -40px;
  left: 50%;
  transform: translateX(-50%);
  background: #111;
  color: #fff;
  padding: 6px 12px;
  border-radius: 5px;
  font-size: 0.9rem;
  opacity: 0;
  visibility: hidden;
  transition: all 0.3s ease;
  white-space: nowrap;
  box-shadow: 0 3px 10px rgba(0,0,0,0.2);
}
body.dark .tooltip {
  background: #f1f5f9;
  color: #0f172a;
  box-shadow: 0 3px 10px rgba(255,255,255,0.1);
}
.icon-content:hover .tooltip {
  opacity: 1;
  visibility: visible;
  top: -55px;
}

/* Circle Buttons */
.icon-content a {
  width: clamp(60px, 18vw, 80px);   /* responsive circle size */
  height: clamp(60px, 18vw, 80px);
  border-radius: 50%;
  display: flex;
  justify-content: center;
  align-items: center;
  background: #fff;
  color: #444;
  font-size: clamp(20px, 6vw, 32px); /* responsive icon size */
  text-decoration: none;
  position: relative;
  overflow: hidden;
  transition: all 0.3s ease;
}
body.dark .icon-content a {
  background: #1e293b;
  color: #94a3b8;
}

.icon-content a::before {
  content: "";
  position: absolute;
  inset: 0;
  border-radius: 50%;
  background: currentColor;
  transform: scale(0);
  transition: transform 0.3s ease;
  z-index: 0;
}

.icon-content a i {
  position: relative;
  z-index: 1;
  transition: color 0.3s ease;
}

.icon-content a:hover::before {
  transform: scale(1);
}
.icon-content a:hover i {
  color: #fff;
}

/* Button Colors */
.login a {
  color: #007bff;
}
.signup a {
  color: #28a745;
}

/* Night/Day Toggle */
.theme-toggle {
  position: absolute;
  top: 20px;
  right: 20px;
  width: 45px;
  height: 45px;
  border-radius: 50%;
  display: flex;
  justify-content: center;
  align-items: center;
  background: #fff;
  color: #333;
  font-size: 20px;
  cursor: pointer;
  border: 2px solid #ddd;
  transition: all 0.3s ease;
}
.theme-toggle:hover {
  transform: scale(1.1);
}
body.dark .theme-toggle {
  background: #1e293b;
  color: #f1f5f9;
  border-color: #334155;
}

/* Extra small devices fix */
@media (max-width: 400px) {
  h1 {
    font-size: 1.6rem;
  }
  p.subtitle {
    font-size: 0.9rem;
  }
}