@import url('https://fonts.googleapis.com/css2?family=Poppins:wght@400;600;700&display=swap');

/* ======= MODERN, SOBER COLOR VARIABLES ======= */
:root {
  /* LIGHT MODE: Soft, clean, modern palette */
  --color-background: whitesmoke; /* very soft gray-blue */
  --color-surface: #fff; /* card/surface */
  --color-primary: #232946; /* dark blue-gray for text */
  --color-secondary: #6e7ca0; /* muted blue-gray */
  --color-border: rgb(168 218 181 / var(--tw-bg-opacity, 1)); /* subtle border */
  --color-accent: #3e8ed0; /* modern blue accent */
  --color-accent-hover: #215e9b; /* blue accent hover */
  --color-shadow: 0 4px 24px rgba(62, 142, 208, 0.09);
  --radius: 1.2rem;
  --font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --transition: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  --switch-size: 1.7rem;
  --anim-spring: cubic-bezier(0.22, 1, 0.36, 1);
}

[data-theme='dark'] {
  --color-background: #0f1419;
  --color-surface: #1c1f26;
  --color-primary: #e6edf3;
  --color-secondary: #8d96a0;
  --color-border: #30363d;
  --color-accent: #3b82f6;
  --color-accent-hover: #60a5fa;
  --color-shadow: 0 4px 16px rgba(0, 0, 0, 0.3);
}

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

body {
  background: var(--color-background);
  color: var(--color-primary);
  font-family: var(--font-family);
  margin: 0;
  min-height: 100vh;
  font-size: 1rem;
  line-height: 1.7;
  transition:
    background var(--transition),
    color var(--transition);
}

/* ========== HEADER ========== */
.header {
  display: flex;
  align-items: center;
  justify-content: center;
  position: relative;
  padding: 2.5rem 2rem 2rem 2rem;
  background: var(--color-background);
}

.header__brand {
  font-weight: 700;
  font-size: 2rem;
  letter-spacing: -0.02em;
  color: var(--color-primary);
  margin: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  flex: 1;
  text-align: center;
}
.brand-accent {
  color: var(--color-accent);
  font-weight: 700;
}
.brand-subtitle {
  font-size: 1rem;
  font-weight: 500;
  color: var(--color-secondary);
  opacity: 0.8;
}

/* ========== THEME TOGGLE ========== */
.theme-toggle {
  position: absolute;
  right: 2rem;
  background: var(--color-surface);
  border: 2px solid var(--color-border);
  border-radius: 2rem;
  width: 3rem;
  height: 3rem;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all 0.3s ease;
  box-shadow: var(--color-shadow);
}

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

.theme-toggle__icon {
  width: 1.5rem;
  height: 1.5rem;
  stroke: var(--color-primary);
  stroke-width: 2;
  stroke-linecap: round;
  stroke-linejoin: round;
}

.sun {
  fill: var(--color-primary);
  transition: all 0.3s ease;
}

.sun-rays {
  transition: all 0.3s ease;
  transform-origin: center;
}

.moon {
  fill: var(--color-primary);
  transition: all 0.3s ease;
  opacity: 0;
  transform: scale(0) rotate(-90deg);
}

[data-theme='dark'] .sun,
[data-theme='dark'] .sun-rays {
  opacity: 0;
  transform: scale(0) rotate(90deg);
}

[data-theme='dark'] .moon {
  opacity: 1;
  transform: scale(1) rotate(0deg);
}

[data-theme='dark'] .theme-toggle {
  background: #1c1f26;
  border-color: #30363d;
}

[data-theme='dark'] .theme-toggle:hover {
  border-color: #3b82f6;
  box-shadow: 0 4px 16px rgba(59, 130, 246, 0.2);
}

/* ========== MAIN ========== */
main {
  display: flex;
  flex-direction: column;
  align-items: center;
  padding: 0 2rem 4rem;
  margin: 0 auto;
  max-width: 1400px;
}

h1 {
  font-size: 2.5rem;
  font-weight: 700;
  margin: 2.5rem 0 3rem 0;
  color: var(--color-primary);
  text-align: center;
  letter-spacing: -0.02em;
  font-family: var(--font-family);
}

/* ========== CARDS ========== */
.cards-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 2rem;
  width: 100%;
}

@media (min-width: 640px) {
  .cards-grid {
    grid-template-columns: repeat(2, 1fr);
    gap: 2rem;
  }
}

@media (min-width: 1024px) {
  .cards-grid {
    grid-template-columns: repeat(4, 1fr);
    gap: 2.5rem;
  }
}

.card {
  background: var(--color-surface);
  border-radius: var(--radius);
  box-shadow: var(--color-shadow);
  border: 2px solid var(--color-border);
  padding: 2.25rem 2rem;
  display: flex;
  flex-direction: column;
  gap: 1.1rem;
  min-width: 0;
  width: 100%;
  height: 100%;
  min-height: 180px;
  opacity: 0;
  transform: translateY(30px) scale(0.97);
  animation: card-fade-in 0.7s var(--anim-spring) forwards;
  will-change: transform, box-shadow, opacity;
  position: relative;
  overflow: hidden;
  transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  backdrop-filter: blur(10px);
}
.card::before {
  content: '';
  position: absolute;
  inset: -2px;
  border-radius: var(--radius);
  padding: 2px;
  background: linear-gradient(90deg, #00f, #0ff, #0f0, #ff0, #f00, #f0f, #00f);
  background-size: 300% 100%;
  -webkit-mask: linear-gradient(#fff 0 0) content-box, linear-gradient(#fff 0 0);
  -webkit-mask-composite: xor;
  mask-composite: exclude;
  opacity: 1;
  animation: electric-border 3s linear infinite;
}
[data-theme='dark'] .card::before {
  background: linear-gradient(90deg, #00f, #0ff, #0f0, #ff0, #f00, #f0f, #00f);
  background-size: 300% 100%;
}
.card:hover::before {
  animation: electric-border 1.5s linear infinite;
}
@keyframes electric-border {
  0% {
    background-position: 0% 50%;
  }
  100% {
    background-position: 300% 50%;
  }
}
@keyframes card-fade-in {
  to {
    opacity: 1;
    transform: translateY(0) scale(1);
  }
}
.card:hover,
.card:focus-within {
  border-color: transparent;
  transform: translateY(-4px);
  animation: fire-glow 2.5s ease-in-out infinite;
}

@keyframes fire-glow {
  0%, 100% {
    box-shadow: 0 8px 32px rgba(255, 100, 0, 0.15), 0 4px 16px rgba(255, 140, 0, 0.12), 0 0 40px rgba(255, 120, 0, 0.08);
  }
  50% {
    box-shadow: 0 10px 40px rgba(255, 140, 0, 0.2), 0 5px 20px rgba(255, 100, 0, 0.15), 0 0 50px rgba(255, 160, 0, 0.1);
  }
}
[data-theme='dark'] .card {
  background: #1c1f26;
  border-color: rgba(255, 255, 255, 0.1);
  box-shadow: 0 4px 16px rgba(0, 0, 0, 0.4), 0 2px 8px rgba(0, 0, 0, 0.3);
}

[data-theme='dark'] .card:hover,
[data-theme='dark'] .card:focus-within {
  border-color: transparent;
  background: #21252e;
  animation: lightning-glow 2.5s ease-in-out infinite;
}

@keyframes lightning-glow {
  0%, 100% {
    box-shadow: 0 8px 32px rgba(59, 130, 246, 0.2), 0 4px 16px rgba(96, 165, 250, 0.15), 0 0 40px rgba(59, 130, 246, 0.1);
  }
  50% {
    box-shadow: 0 10px 40px rgba(96, 165, 250, 0.25), 0 5px 20px rgba(59, 130, 246, 0.2), 0 0 50px rgba(147, 197, 253, 0.15);
  }
}

/* Subtle ripple effect on card click (sober, not flashy) */
.card:active {
  animation: card-ripple 0.45s var(--anim-spring);
}
@keyframes card-ripple {
  0% {
    box-shadow: 0 0 0 0px var(--color-accent-hover);
  }
  60% {
    box-shadow: 0 0 0 12px rgba(62, 142, 208, 0.09);
  }
  100% {
    box-shadow: 0 18px 38px rgba(62, 142, 208, 0.17);
  }
}

.card-link {
  text-decoration: none;
  display: block;
}
.card h2 {
  font-size: 1.45rem;
  margin: 0;
  font-weight: 700;
  letter-spacing: -0.03em;
  font-family: var(--font-family);
  background: linear-gradient(135deg, var(--color-primary), var(--color-accent));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  transition: all 0.3s;
}
.card-link:hover .card h2 {
  background: linear-gradient(135deg, var(--color-accent), var(--color-primary));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  transform: translateX(2px);
}
.card p {
  color: var(--color-secondary);
  font-size: 1.05rem;
  margin: 0;
  line-height: 1.7;
  font-family: var(--font-family);
  flex-grow: 1;
  font-weight: 400;
}

/* ========== LINKS ========== */

/* ========== MOBILE ========== */
@media (max-width: 640px) {
  .header {
    padding: 1rem 1rem;
    flex-wrap: wrap;
  }
  .header__brand {
    font-size: 1.25rem;
    flex-direction: column;
    align-items: flex-start;
    gap: 0.25rem;
  }
  .brand-subtitle {
    font-size: 0.85rem;
  }
  main {
    padding: 0 1rem 2rem;
  }
  .cards-grid {
    gap: 1.25rem;
  }
  .card {
    padding: 1.5rem 1.25rem;
    min-height: 140px;
    gap: 0.85rem;
  }
  .card h2 {
    font-size: 1.25rem;
  }
  .card p {
    font-size: 0.95rem;
    line-height: 1.6;
  }
  .theme-toggle {
    right: 1rem;
    width: 2.5rem;
    height: 2.5rem;
  }
  .theme-toggle__icon {
    width: 1.2rem;
    height: 1.2rem;
  }
}

@media (max-width: 400px) {
  .header {
    padding: 0.85rem 0.75rem;
  }
  .header__brand {
    font-size: 1.1rem;
  }
  .brand-subtitle {
    font-size: 0.8rem;
  }
  main {
    padding: 0 0.75rem 1.5rem;
  }
  .cards-grid {
    gap: 1rem;
  }
  .card {
    padding: 1.25rem 1rem;
    min-height: 130px;
  }
  .card h2 {
    font-size: 1.15rem;
  }
  .card p {
    font-size: 0.9rem;
  }
  .theme-toggle {
    right: 0.75rem;
  }
}

/* Accessibility */
.card-link:focus {
  outline: none;
}
.theme-toggle:focus {
  outline: 2px solid var(--color-accent);
  outline-offset: 2px;
}