/* ============================================================================
   GLOBAL STYLES & DESIGN SYSTEM
   ============================================================================ */

:root {
  /* Colors */
  --color-primary: #faff69;
  --color-primary-dark: #151515;
  --color-bg: #000000;
  --color-bg-overlay: rgba(0, 0, 0, 0.8);
  --color-text: #ffffff;
  --color-text-secondary: #a0a0a0;
  --color-border: rgba(65, 65, 65, 0.8);
  --color-accent-green: #166534;
  --color-accent-dark: #141414;

  /* Spacing */
  --space-2: 8px;
  --space-3: 12px;
  --space-4: 16px;
  --space-6: 24px;
  --space-8: 32px;
  --space-12: 48px;
  --space-20: 80px;

  /* Typography */
  --font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --font-weight-semibold: 600;
  --font-weight-bold: 700;
  --font-weight-black: 900;
  --line-height-tight: 1.0;
  --line-height-relaxed: 1.6;

  /* Transitions */
  --transition-fast: 200ms;
  --transition-normal: 300ms;
  --transition-slow: 600ms;
  --transition-page: 700ms;
  --easing-out: cubic-bezier(0.34, 1.56, 0.64, 1);
  --easing-standard: cubic-bezier(0.4, 0, 0.2, 1);

  /* Sizing */
  --radius-lg: 8px;
  --radius-full: 9999px;

  /* Viewport */
  --viewport-sm: 640px;
  --viewport-lg: 1024px;
}

* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

html, body {
  width: 100%;
  height: 100%;
  font-family: var(--font-family);
  background: var(--color-bg);
  color: var(--color-text-secondary);
  line-height: var(--line-height-relaxed);
}

#app {
  width: 100%;
  height: 100vh;
  overflow: hidden;
}

/* ============================================================================
   TYPOGRAPHY
   ============================================================================ */

h1, h2, h3, h4, h5, h6 {
  color: var(--color-text);
  font-weight: var(--font-weight-black);
  margin: 0;
}

h1 {
  line-height: var(--line-height-tight);
}

h2 {
  font-weight: var(--font-weight-black);
  margin-bottom: var(--space-12);
}

h3 {
  font-weight: var(--font-weight-bold);
  color: var(--color-text);
}

p {
  color: var(--color-text-secondary);
  line-height: var(--line-height-relaxed);
}

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

a:hover {
  opacity: 0.8;
}

/* ============================================================================
   BUTTONS & INTERACTIVE ELEMENTS
   ============================================================================ */

button {
  font-family: var(--font-family);
  font-weight: var(--font-weight-bold);
  border-radius: var(--radius-lg);
  transition: all var(--transition-normal) ease;
  cursor: pointer;
}

/* 移除 button:hover，改用 @media (hover) 来区分触屏/鼠标设备 */
@media (hover: hover) {
  button:hover {
    transform: scale(1.05);
  }
}

button:active {
  transform: scale(0.95);
}

.nav-btn {
  background: none;
  border: none;
  padding: 0;
  font-size: clamp(10px, 1.5vw, 12px);
  font-weight: var(--font-weight-semibold);
  text-transform: uppercase;
  letter-spacing: 0.7px;
  color: var(--color-text-secondary);
  white-space: nowrap;
  transition: color var(--transition-normal) ease;
}

.nav-btn[data-active="true"] {
  color: var(--color-primary);
}

@media (hover: hover) {
  .nav-btn:hover {
    color: var(--color-primary);
    transform: none;
  }
}

.goto-page-btn {
  padding: clamp(8px, 2vw, 12px) clamp(24px, 3vw, 32px);
  font-size: 14px;
  font-weight: var(--font-weight-bold);
  border-radius: var(--radius-lg);
  transition: all var(--transition-normal) ease;
}

/* ============================================================================
   LAYOUT & CONTAINERS
   ============================================================================ */

nav {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: clamp(12px, 2vw, 24px) clamp(16px, 3vw, 48px);
  border-bottom: 1px solid var(--color-border);
  background: var(--color-bg-overlay);
  backdrop-filter: blur(10px);
  gap: clamp(8px, 2vw, 32px);
  flex-wrap: wrap;
}

nav > div:first-child {
  font-size: clamp(18px, 2vw, 24px);
  font-weight: var(--font-weight-black);
  letter-spacing: 0.05em;
  color: var(--color-primary);
}

nav ul {
  list-style: none;
  display: flex;
  gap: clamp(8px, 1.5vw, 24px);
  align-items: center;
  flex-wrap: wrap;
  justify-content: center;
}

.max-w-6xl {
  max-width: 1280px;
  margin-left: auto;
  margin-right: auto;
}

.max-w-3xl {
  max-width: 768px;
  margin-left: auto;
  margin-right: auto;
}

/* ============================================================================
   RESPONSIVE UTILITY CLASSES
   ============================================================================ */

/* Flexbox */
.flex {
  display: flex;
}

.flex-col {
  flex-direction: column;
}

.flex-row {
  flex-direction: row;
}

.items-center {
  align-items: center;
}

.items-start {
  align-items: flex-start;
}

.justify-between {
  justify-content: space-between;
}

.justify-center {
  justify-content: center;
}

.gap-3 {
  gap: var(--space-3);
}

.gap-4 {
  gap: var(--space-4);
}

.gap-6 {
  gap: var(--space-6);
}

.gap-8 {
  gap: var(--space-8);
}

/* Grid */
.grid {
  display: grid;
}

.grid-cols-1 {
  grid-template-columns: 1fr;
}

/* ============================================================================
   MOBILE FIRST: 手机端 (< 640px)
   ============================================================================ */

/* Padding - 手机端缩小 */
.p-6 {
  padding: var(--space-4);
}

.p-8 {
  padding: var(--space-6);
}

.px-4 {
  padding-left: var(--space-3);
  padding-right: var(--space-3);
}

.px-6 {
  padding-left: var(--space-4);
  padding-right: var(--space-4);
}

.px-8 {
  padding-left: var(--space-6);
  padding-right: var(--space-6);
}

.py-2 {
  padding-top: 8px;
  padding-bottom: 8px;
}

.py-3 {
  padding-top: var(--space-3);
  padding-bottom: var(--space-3);
}

.pt-16 {
  padding-top: 32px;
}

.pb-6 {
  padding-bottom: var(--space-4);
}

.pb-8 {
  padding-bottom: var(--space-6);
}

/* Text sizing - 手机端缩小 */
.text-xs {
  font-size: 12px;
}

.text-sm {
  font-size: 13px;
}

.text-base {
  font-size: 14px;
}

.text-lg {
  font-size: 15px;
}

.text-xl {
  font-size: 16px;
}

.text-3xl {
  font-size: 24px;
}

/* Spacing */
.space-y-2 > * + * {
  margin-top: 8px;
}

.space-y-3 > * + * {
  margin-top: var(--space-3);
}

.space-y-4 > * + * {
  margin-top: var(--space-4);
}

.space-y-6 > * + * {
  margin-top: var(--space-6);
}

.space-y-8 > * + * {
  margin-top: var(--space-6);
}

.space-y-12 > * + * {
  margin-top: var(--space-8);
}

.space-y-20 > * + * {
  margin-top: var(--space-12);
}

.mb-4 {
  margin-bottom: var(--space-3);
}

.mb-6 {
  margin-bottom: var(--space-4);
}

.mb-8 {
  margin-bottom: var(--space-6);
}

.mb-12 {
  margin-bottom: var(--space-8);
}

/* Display */
.absolute {
  position: absolute;
}

.fixed {
  position: fixed;
}

.relative {
  position: relative;
}

.inset-0 {
  top: 0;
  right: 0;
  bottom: 0;
  left: 0;
}

.overflow-hidden {
  overflow: hidden;
}

.overflow-y-auto {
  overflow-y: auto;
}

.z-40 {
  z-index: 40;
}

.z-50 {
  z-index: 50;
}

/* Width & Height */
.w-full {
  width: 100%;
}

.h-full {
  height: 100%;
}

.h-screen {
  height: 100vh;
}

.w-12 {
  width: 44px;
}

.h-12 {
  height: 44px;
}

/* Font weights */
.font-semibold {
  font-weight: var(--font-weight-semibold);
}

.font-bold {
  font-weight: var(--font-weight-bold);
}

.font-black {
  font-weight: var(--font-weight-black);
}

/* Text alignment */
.text-center {
  text-align: center;
}

/* Text properties */
.uppercase {
  text-transform: uppercase;
}

.leading-tight {
  line-height: var(--line-height-tight);
}

.leading-relaxed {
  line-height: var(--line-height-relaxed);
}

.tracking-widest {
  letter-spacing: 1.4px;
}

.tracking-wider {
  letter-spacing: 0.05em;
}

/* Border & Background */
.border {
  border: 1px solid var(--color-border);
}

.border-b {
  border-bottom: 1px solid var(--color-border);
}

.border-2 {
  border: 2px solid var(--color-border);
}

.rounded {
  border-radius: var(--radius-lg);
}

.rounded-lg {
  border-radius: var(--radius-lg);
}

.rounded-full {
  border-radius: var(--radius-full);
}

/* Transform */
.transition-all {
  transition: all var(--transition-normal) ease;
}

.transition-opacity {
  transition: opacity var(--transition-slow) ease;
}

.transition-colors {
  transition: color var(--transition-normal) ease;
}

.duration-200 {
  transition-duration: var(--transition-fast);
}

.duration-600 {
  transition-duration: var(--transition-slow);
}

.duration-700 {
  transition-duration: var(--transition-page);
}

@media (hover: hover) {
  .hover\:scale-105:hover {
    transform: scale(1.05);
  }

  .hover\:scale-110:hover {
    transform: scale(1.1);
  }

  .hover\:opacity-80:hover {
    opacity: 0.8;
  }
}

.active\:scale-95:active {
  transform: scale(0.95);
}

/* ============================================================================
   TABLET & DESKTOP: 640px 及以上
   ============================================================================ */

@media (min-width: 640px) {
  /* Padding 恢复正常 */
  .p-6 {
    padding: var(--space-6);
  }

  .p-8 {
    padding: var(--space-8);
  }

  .px-4 {
    padding-left: var(--space-4);
    padding-right: var(--space-4);
  }

  .px-6 {
    padding-left: var(--space-6);
    padding-right: var(--space-6);
  }

  .sm\:p-8 {
    padding: var(--space-8);
  }

  .sm\:px-8 {
    padding-left: var(--space-8);
    padding-right: var(--space-8);
  }

  .sm\:py-3 {
    padding-top: var(--space-3);
    padding-bottom: var(--space-3);
  }

  .sm\:pt-20 {
    padding-top: 80px;
  }

  .sm\:pb-8 {
    padding-bottom: var(--space-8);
  }

  .pt-16 {
    padding-top: 64px;
  }

  .pb-6 {
    padding-bottom: var(--space-6);
  }

  /* Text sizing 恢复正常 */
  .text-sm {
    font-size: 14px;
  }

  .text-base {
    font-size: 16px;
  }

  .text-lg {
    font-size: 18px;
  }

  .text-xl {
    font-size: 20px;
  }

  .text-3xl {
    font-size: 30px;
  }

  .sm\:text-sm {
    font-size: 14px;
  }

  .sm\:text-base {
    font-size: 16px;
  }

  .sm\:text-lg {
    font-size: 18px;
  }

  .sm\:text-xl {
    font-size: 20px;
  }

  .sm\:text-4xl {
    font-size: 36px;
  }

  /* Spacing 恢复正常 */
  .space-y-8 > * + * {
    margin-top: var(--space-8);
  }

  .space-y-12 > * + * {
    margin-top: var(--space-12);
  }

  .space-y-20 > * + * {
    margin-top: var(--space-20);
  }

  .mb-4 {
    margin-bottom: var(--space-4);
  }

  .mb-6 {
    margin-bottom: var(--space-6);
  }

  .mb-8 {
    margin-bottom: var(--space-8);
  }

  .mb-12 {
    margin-bottom: var(--space-12);
  }

  /* Grid */
  .sm\:grid-cols-2 {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .sm\:gap-8 {
    gap: var(--space-8);
  }

  .sm\:flex-row {
    flex-direction: row;
  }

  .sm\:space-y-8 > * + * {
    margin-top: var(--space-8);
  }

  .sm\:space-y-12 > * + * {
    margin-top: var(--space-12);
  }

  .sm\:space-y-20 > * + * {
    margin-top: var(--space-20);
  }

  .sm\:w-14 {
    width: 56px;
  }

  .sm\:h-14 {
    height: 56px;
  }
}

@media (min-width: 1024px) {
  .lg\:text-5xl {
    font-size: 48px;
  }

  .lg\:grid-cols-3 {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }

  .lg\:gap-8 {
    gap: var(--space-8);
  }

  .lg\:px-12 {
    padding-left: 48px;
    padding-right: 48px;
  }

  .lg\:pt-24 {
    padding-top: 96px;
  }

  .lg\:pb-12 {
    padding-bottom: 48px;
  }
}

/* ============================================================================
   触屏设备优化
   ============================================================================ */

@media (hover: none) and (pointer: coarse) {
  /* 在触屏设备上增加按钮的点击目标大小 */
  .nav-btn {
    padding: 8px 12px;
    border-radius: 4px;
  }

  .goto-page-btn {
    padding: 12px 20px;
    min-height: 48px;
  }
}