/* =========================================
   CSS VARIABLES — LIGHT MODE (default)
   ========================================= */
:root {
  --bg:           #f4f7fb;
  --surface:      #ffffff;
  --primary:      #2563eb;
  --primary-soft: #dbeafe;
  --text-main:    #0f172a;
  --text-muted:   #64748b;
  --border:       #e2e8f0;
  --link:         #2563eb;
  --circle-1:     rgba(37, 99, 235, 0.08);
  --circle-2:     rgba(99, 179, 237, 0.12);
  --circle-3:     rgba(16, 185, 129, 0.07);
  --toggle-bg:    #e2e8f0;
  --toggle-color: #475569;
  --shadow:       0 4px 24px rgba(15, 23, 42, 0.08);
}

/* =========================================
   DARK MODE
   ========================================= */
body.dark {
  --bg:           #0b1120;
  --surface:      #131c2e;
  --primary:      #60a5fa;
  --primary-soft: #1e3a5f;
  --text-main:    #f1f5f9;
  --text-muted:   #94a3b8;
  --border:       #1e293b;
  --link:         #93c5fd;
  --circle-1:     rgba(96, 165, 250, 0.07);
  --circle-2:     rgba(99, 179, 237, 0.06);
  --circle-3:     rgba(52, 211, 153, 0.05);
  --toggle-bg:    #1e293b;
  --toggle-color: #94a3b8;
  --shadow:       0 4px 24px rgba(0, 0, 0, 0.4);
}

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

html {
  font-size: 16px;
  scroll-behavior: smooth;
}

body {
  font-family: 'Inter', system-ui, sans-serif;
  background-color: var(--bg);
  color: var(--text-main);
  min-height: 100dvh;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: background-color 0.35s ease, color 0.35s ease;
  overflow: hidden;
  position: relative;
}

/* =========================================
   BACKGROUND DECORATIVE CIRCLES
   ========================================= */
.bg-circles {
  position: fixed;
  inset: 0;
  pointer-events: none;
  z-index: 0;
}

.circle {
  position: absolute;
  border-radius: 50%;
  filter: blur(60px);
}

.circle-1 {
  width: 500px;
  height: 500px;
  background: var(--circle-1);
  top: -120px;
  left: -100px;
}

.circle-2 {
  width: 400px;
  height: 400px;
  background: var(--circle-2);
  bottom: -80px;
  right: -80px;
}

.circle-3 {
  width: 280px;
  height: 280px;
  background: var(--circle-3);
  top: 50%;
  left: 60%;
  transform: translate(-50%, -50%);
}

/* =========================================
   THEME TOGGLE BUTTON
   ========================================= */
.theme-toggle {
  position: fixed;
  top: 1.25rem;
  right: 1.25rem;
  z-index: 100;
  display: flex;
  align-items: center;
  justify-content: center;
  width: 44px;
  height: 44px;
  border-radius: 50%;
  border: 1.5px solid var(--border);
  background: var(--toggle-bg);
  color: var(--toggle-color);
  cursor: pointer;
  transition: background 0.3s ease, border-color 0.3s ease, color 0.3s ease, transform 0.2s ease;
}

.theme-toggle:hover {
  transform: scale(1.1);
  color: var(--primary);
  border-color: var(--primary);
}

.icon {
  display: flex;
  align-items: center;
  justify-content: center;
  transition: opacity 0.2s ease, transform 0.3s ease;
}

/* By default (light mode) → show sun, hide moon */
.icon-sun  { opacity: 1; display: flex; }
.icon-moon { opacity: 0; display: none; }

/* Dark mode → hide sun, show moon */
body.dark .icon-sun  { opacity: 0; display: none; }
body.dark .icon-moon { opacity: 1; display: flex; }

/* =========================================
   MAIN CONTAINER
   ========================================= */
.container {
  position: relative;
  z-index: 1;
  width: 100%;
  max-width: 640px;
  margin: 0 auto;
  padding: 2.5rem 1.5rem;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 2rem;
  text-align: center;
}

/* =========================================
   BRAND / LOGO
   ========================================= */
.brand {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  animation: fadeDown 0.6s ease both;
}

.logo-mark {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 52px;
  height: 52px;
  border-radius: 14px;
  background: var(--primary-soft);
  color: var(--primary);
  transition: background 0.3s ease, color 0.3s ease;
}

.brand-name {
  font-size: 1.35rem;
  font-weight: 700;
  letter-spacing: -0.02em;
  color: var(--text-main);
  transition: color 0.3s ease;
}

/* =========================================
   HERO SECTION
   ========================================= */
.hero {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 1.25rem;
  animation: fadeUp 0.7s ease 0.15s both;
}

.badge {
  display: inline-flex;
  align-items: center;
  padding: 0.3rem 1rem;
  border-radius: 999px;
  background: var(--primary-soft);
  color: var(--primary);
  font-size: 0.78rem;
  font-weight: 600;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  transition: background 0.3s ease, color 0.3s ease;
}

.headline {
  font-size: clamp(1.9rem, 5vw, 2.75rem);
  font-weight: 700;
  line-height: 1.2;
  letter-spacing: -0.03em;
  color: var(--text-main);
  transition: color 0.3s ease;
}

.subheadline {
  font-size: 1.05rem;
  font-weight: 400;
  line-height: 1.7;
  color: var(--text-muted);
  max-width: 480px;
  transition: color 0.3s ease;
}

/* =========================================
   DIVIDER
   ========================================= */
.divider {
  width: 60px;
  height: 3px;
  border-radius: 999px;
  background: var(--primary-soft);
  animation: fadeUp 0.7s ease 0.3s both;
  transition: background 0.3s ease;
}

/* =========================================
   FOOTER
   ========================================= */
.footer {
  animation: fadeUp 0.7s ease 0.45s both;
}

.footer-text {
  font-size: 0.9rem;
  color: var(--text-muted);
  transition: color 0.3s ease;
}

.link {
  color: var(--link);
  text-decoration: none;
  font-weight: 500;
  border-bottom: 1px solid transparent;
  transition: border-color 0.2s ease;
}

.link:hover {
  border-bottom-color: var(--link);
}

/* =========================================
   ANIMATIONS
   ========================================= */
@keyframes fadeUp {
  from { opacity: 0; transform: translateY(18px); }
  to   { opacity: 1; transform: translateY(0); }
}

@keyframes fadeDown {
  from { opacity: 0; transform: translateY(-12px); }
  to   { opacity: 1; transform: translateY(0); }
}

/* =========================================
   RESPONSIVE
   ========================================= */
@media (max-width: 480px) {
  .brand-name { font-size: 1.1rem; }
  .container  { padding: 2rem 1.25rem; gap: 1.75rem; }
}