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

html {
  scroll-behavior: smooth;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

body {
  font-family: var(--font-body);
  font-size: var(--text-size);
  line-height: var(--lh-text);
  color: var(--color-text);
  background-color: var(--color-bg);
  overflow-x: hidden;
}

body.no-scroll {
  overflow: hidden;
}

body.loading {
  overflow: hidden;
}

img {
  max-width: 100%;
  height: auto;
  display: block;
}

a {
  color: inherit;
  text-decoration: none;
  transition: color var(--transition);
}

a:hover {
  color: var(--color-accent);
}

button {
  font-family: inherit;
  cursor: pointer;
  border: none;
  background: none;
}

ul, ol {
  list-style: none;
}

input, textarea, select {
  font-family: inherit;
  font-size: inherit;
}

h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-heading);
  font-weight: 400;
  line-height: var(--lh-heading);
}

h1 { font-size: var(--h1-size); }
h2 { font-size: var(--h2-size); }
h3 { font-size: var(--h3-size); }

/* === Container === */
.container {
  max-width: var(--container-width);
  margin: 0 auto;
  padding: 0 var(--container-padding);
}

/* === Section === */
.section {
  padding: var(--section-gap) 0;
}

.section--alt {
  background-color: var(--color-bg-alt);
}

.section--dark {
  background-color: var(--color-dark);
  color: var(--color-white);
}

.section__header {
  margin-bottom: clamp(2rem, 4vw, 4rem);
}

.section__subtitle {
  font-size: var(--text-size);
  color: var(--color-text-secondary);
  margin-top: 1rem;
  max-width: 640px;
}

/* === Buttons === */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  height: 52px;
  padding: 0 28px;
  font-size: 0.9375rem;
  font-weight: 500;
  letter-spacing: 0.02em;
  border-radius: var(--radius);
  transition: all var(--transition);
  white-space: nowrap;
}

.btn--primary {
  background-color: var(--color-btn-bg);
  color: var(--color-btn-text);
}

.btn--primary:hover {
  background-color: var(--color-btn-hover);
  color: var(--color-btn-text);
}

.btn--outline {
  background: transparent;
  border: 1px solid var(--color-text);
  color: var(--color-text);
}

.btn--outline:hover {
  background-color: var(--color-text);
  color: var(--color-bg);
}

.btn--white {
  background-color: var(--color-white);
  color: var(--color-text);
}

.btn--white:hover {
  background-color: var(--color-accent);
  color: var(--color-white);
}

.btn--link {
  height: auto;
  padding: 0;
  font-size: var(--text-size);
  color: var(--color-text);
  border-bottom: 1px solid var(--color-border);
  border-radius: 0;
  padding-bottom: 4px;
}

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

/* === Reveal Animations === */
.reveal {
  opacity: 0;
  transform: translateY(40px);
  transition: opacity var(--transition-slow), transform var(--transition-slow);
}

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

.reveal-delay-1 { transition-delay: 0.1s; }
.reveal-delay-2 { transition-delay: 0.2s; }
.reveal-delay-3 { transition-delay: 0.3s; }
.reveal-delay-4 { transition-delay: 0.4s; }
.reveal-delay-5 { transition-delay: 0.5s; }

/* === Utility === */
.text-center { text-align: center; }
.text-secondary { color: var(--color-text-secondary); }

/* === Page transition === */
#app {
  min-height: 100vh;
}

.page-enter {
  opacity: 0;
}

.page-enter-active {
  opacity: 1;
  transition: opacity 0.4s ease;
}

/* === Filter Buttons === */
.filter__btn {
  padding: 8px 20px;
  font-size: 0.875rem;
  border: 1px solid var(--color-border);
  border-radius: 100px;
  background: transparent;
  color: var(--color-text-secondary);
  cursor: pointer;
  transition: all var(--transition);
  font-family: var(--font-body);
}

.filter__btn:hover,
.filter__btn.active {
  background-color: var(--color-text);
  color: var(--color-bg);
  border-color: var(--color-text);
}

/* === Selection === */
::selection {
  background-color: var(--color-accent);
  color: var(--color-white);
}

/* === Scroll to top button === */
.scroll-top {
  position: fixed;
  bottom: 32px;
  right: 32px;
  width: 48px;
  height: 48px;
  border-radius: 50%;
  background-color: var(--color-text);
  color: var(--color-bg);
  display: flex;
  align-items: center;
  justify-content: center;
  opacity: 0;
  visibility: hidden;
  transition: all var(--transition);
  z-index: 900;
  cursor: pointer;
  border: none;
}

.scroll-top.visible {
  opacity: 1;
  visibility: visible;
}

.scroll-top:hover {
  background-color: var(--color-accent);
}

.scroll-top svg {
  width: 20px;
  height: 20px;
  stroke: currentColor;
  fill: none;
  stroke-width: 2;
}