/* ==========================================================================
   基础层：排版、重置、通用原子类
   ========================================================================== */

*,
*::before,
*::after {
  box-sizing: border-box;
}

html,
body {
  height: 100%;
}

html {
  -webkit-text-size-adjust: 100%;
}

body {
  margin: 0;
  background: var(--bg);
  color: var(--text-1);
  font-family: var(--font-text);
  font-size: var(--fs-body);
  line-height: 1.47;
  letter-spacing: var(--ls-body);
  font-synthesis-weight: none;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  text-rendering: optimizeLegibility;
  overflow: hidden;
  overscroll-behavior: none;
}

h1,
h2,
h3,
h4 {
  margin: 0;
  font-family: var(--font-display);
  font-weight: 600;
  letter-spacing: var(--ls-title);
  line-height: 1.16;
}

p {
  margin: 0;
}

a {
  color: var(--blue);
  text-decoration: none;
  transition: opacity var(--dur-fast) var(--ease-out);
}

a:hover {
  text-decoration: underline;
  text-underline-offset: 2px;
}

button,
input,
textarea,
select {
  font-family: inherit;
  font-size: inherit;
  letter-spacing: inherit;
  color: inherit;
}

button {
  border: 0;
  background: none;
  padding: 0;
  cursor: pointer;
  -webkit-tap-highlight-color: transparent;
}

:focus-visible {
  outline: 2px solid var(--blue);
  outline-offset: 2px;
}

::selection {
  background: color-mix(in srgb, var(--blue) 24%, transparent);
}

/* ------------------------------ 滚动条 ------------------------------ */
.scroll-area {
  overflow-y: auto;
  overflow-x: hidden;
  scrollbar-width: thin;
  scrollbar-color: transparent transparent;
  transition: scrollbar-color var(--dur-base) var(--ease-out);
}

.scroll-area:hover {
  scrollbar-color: var(--hairline-strong) transparent;
}

.scroll-area::-webkit-scrollbar {
  width: 10px;
}

.scroll-area::-webkit-scrollbar-thumb {
  background-color: transparent;
  border-radius: var(--r-full);
  border: 3px solid transparent;
  background-clip: content-box;
}

.scroll-area:hover::-webkit-scrollbar-thumb {
  background-color: var(--hairline-strong);
}

/* ------------------------------ 图标 ------------------------------ */
.icon {
  width: 18px;
  height: 18px;
  flex: none;
  display: block;
  stroke: currentColor;
  fill: none;
  stroke-width: 1.6;
  stroke-linecap: round;
  stroke-linejoin: round;
}

.icon-sm {
  width: 15px;
  height: 15px;
  stroke-width: 1.7;
}

/* ------------------------------ 按钮 ------------------------------ */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 6px;
  height: 32px;
  padding: 0 12px;
  border-radius: var(--r-sm);
  font-size: var(--fs-footnote);
  font-weight: 500;
  letter-spacing: var(--ls-small);
  color: var(--text-2);
  background: transparent;
  transition: background-color var(--dur-fast) var(--ease-out),
    color var(--dur-fast) var(--ease-out), transform var(--dur-fast) var(--ease-out);
}

.btn:hover {
  background: var(--hover);
  color: var(--text-1);
}

.btn:active {
  background: var(--pressed);
  transform: scale(0.97);
}

.btn-icon {
  width: 32px;
  height: 32px;
  padding: 0;
  border-radius: var(--r-sm);
}

.btn-primary {
  color: #fff;
  background: var(--blue);
  box-shadow: var(--shadow-xs);
}

.btn-primary:hover {
  background: var(--blue-hover);
  color: #fff;
}

.btn-primary:active {
  background: var(--blue-active);
}

.btn-ghost {
  border: 1px solid var(--hairline);
  background: var(--surface);
}

/* ------------------------------ 工具类 ------------------------------ */
.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip-path: inset(50%);
  white-space: nowrap;
}

.dim {
  color: var(--text-3);
}

.mono {
  font-family: var(--font-mono);
  font-variant-ligatures: none;
}

/* ------------------------------ 动效 ------------------------------ */
@keyframes fade-up {
  from {
    opacity: 0;
    transform: translateY(8px);
  }
  to {
    opacity: 1;
    transform: none;
  }
}

@keyframes fade-in {
  from {
    opacity: 0;
  }
  to {
    opacity: 1;
  }
}

@keyframes breathe {
  0%,
  100% {
    opacity: 0.25;
    transform: scale(0.72);
  }
  50% {
    opacity: 0.9;
    transform: scale(1);
  }
}

@keyframes caret-blink {
  0%,
  45% {
    opacity: 1;
  }
  55%,
  100% {
    opacity: 0.15;
  }
}

@keyframes shimmer {
  from {
    background-position: 200% 0;
  }
  to {
    background-position: -200% 0;
  }
}

@keyframes spin {
  to {
    transform: rotate(360deg);
  }
}

@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }
}