/* ============================================
   StarUML 中文官网 - 公共样式 (Redesign v2)
   主题色: #383838 (深灰) / #3585FF (蓝)
   设计语言: 玻璃拟态 · 渐变光晕 · 微交互
   ============================================ */

/* ---------- CSS Custom Properties ---------- */
:root {
  --c-primary: #3585FF;
  --c-primary-dark: #1a6ae0;
  --c-primary-glow: rgba(53,133,255,.25);
  --c-dark: #383838;
  --c-heading: #0f1729;
  --c-text: #4a5568;
  --c-text-light: #718096;
  --c-border: #e2e8f0;
  --c-surface: #ffffff;
  --c-surface-alt: #f8fafd;
  --c-surface-glass: rgba(255,255,255,.62);
  --radius-sm: 8px;
  --radius-md: 14px;
  --radius-lg: 20px;
  --radius-xl: 28px;
  --radius-pill: 100px;
  --shadow-sm: 0 1px 3px rgba(0,0,0,.04), 0 1px 2px rgba(0,0,0,.06);
  --shadow-md: 0 4px 16px rgba(0,0,0,.06);
  --shadow-lg: 0 12px 40px rgba(0,0,0,.08);
  --shadow-glow: 0 0 40px var(--c-primary-glow);
  --font-base: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Helvetica Neue", Helvetica, Arial, sans-serif;
  --transition-base: .3s cubic-bezier(.4,0,.2,1);
}

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

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

body {
  font-family: var(--font-base);
  color: var(--c-text);
  background: var(--c-surface);
  line-height: 1.75;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  overflow-x: hidden;
}

a {
  color: var(--c-primary);
  text-decoration: none;
  transition: color var(--transition-base);
}

a:hover {
  color: var(--c-primary-dark);
}

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

/* ---------- Typography ---------- */
h1, h2, h3, h4, h5, h6 {
  font-weight: 800;
  line-height: 1.3;
  color: var(--c-heading);
  letter-spacing: -.02em;
}

h1 { font-size: 3.2rem; }
h2 { font-size: 2.25rem; }
h3 { font-size: 1.3rem; }

p {
  margin-bottom: 1rem;
  color: var(--c-text);
}

/* ---------- Container ---------- */
.container {
  width: 100%;
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 24px;
}

/* ---------- Section ---------- */
.section {
  padding: 100px 0;
  position: relative;
}

.section-alt {
  background: var(--c-surface-alt);
}

.section-title {
  text-align: center;
  margin-bottom: 16px;
  font-size: 2.25rem;
  color: var(--c-heading);
  position: relative;
}

.section-title::after {
  content: '';
  display: block;
  width: 48px;
  height: 3px;
  background: linear-gradient(90deg, var(--c-primary), #60a5fa);
  border-radius: 3px;
  margin: 16px auto 0;
}

.section-subtitle {
  text-align: center;
  max-width: 680px;
  margin: 0 auto 56px;
  color: var(--c-text-light);
  font-size: 1.06rem;
  line-height: 1.85;
}

/* ---------- Buttons ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 13px 30px;
  border-radius: var(--radius-pill);
  font-size: .92rem;
  font-weight: 600;
  cursor: pointer;
  border: none;
  transition: all var(--transition-base);
  text-decoration: none;
  position: relative;
  overflow: hidden;
  letter-spacing: .01em;
}

.btn svg {
  width: 17px;
  height: 17px;
  flex-shrink: 0;
}

.btn-primary {
  background: linear-gradient(135deg, #3585FF 0%, #2563eb 100%);
  color: #fff;
  box-shadow: 0 4px 16px rgba(53,133,255,.35), inset 0 1px 0 rgba(255,255,255,.15);
}

.btn-primary::before {
  content: '';
  position: absolute;
  inset: 0;
  background: linear-gradient(135deg, rgba(255,255,255,.15), transparent);
  opacity: 0;
  transition: opacity var(--transition-base);
}

.btn-primary:hover {
  color: #fff;
  box-shadow: 0 8px 28px rgba(53,133,255,.45), inset 0 1px 0 rgba(255,255,255,.2);
  transform: translateY(-2px);
}

.btn-primary:hover::before {
  opacity: 1;
}

.btn-outline {
  background: var(--c-surface-glass);
  color: var(--c-dark);
  border: 1.5px solid var(--c-border);
  -webkit-backdrop-filter: blur(8px);
  backdrop-filter: blur(8px);
}

.btn-outline:hover {
  border-color: var(--c-primary);
  color: var(--c-primary);
  background: rgba(53,133,255,.05);
  transform: translateY(-2px);
  box-shadow: 0 4px 16px rgba(53,133,255,.12);
}

/* ---------- Badge ---------- */
.badge-pro {
  display: inline-flex;
  align-items: center;
  padding: 2px 9px;
  border-radius: var(--radius-pill);
  font-size: .62rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: .8px;
  background: linear-gradient(135deg, #3585FF, #6366f1);
  color: #fff;
  vertical-align: middle;
  margin-left: 6px;
  line-height: 1.7;
}

/* ---------- Grid ---------- */
.grid-2 {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 32px;
  align-items: center;
}

.grid-3 {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}

.grid-4 {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 24px;
}

/* ---------- Card ---------- */
.card {
  background: var(--c-surface);
  border-radius: var(--radius-lg);
  padding: 32px 28px;
  border: 1px solid var(--c-border);
  transition: all var(--transition-base);
  position: relative;
  overflow: hidden;
}

.card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 3px;
  background: linear-gradient(90deg, var(--c-primary), #60a5fa, #818cf8);
  opacity: 0;
  transition: opacity var(--transition-base);
}

.card:hover {
  border-color: rgba(53,133,255,.2);
  box-shadow: 0 8px 32px rgba(53,133,255,.1), 0 0 0 1px rgba(53,133,255,.08);
  transform: translateY(-4px);
}

.card:hover::before {
  opacity: 1;
}

.card-icon {
  width: 52px;
  height: 52px;
  border-radius: var(--radius-md);
  background: linear-gradient(135deg, #eef4ff 0%, #dbeafe 100%);
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 18px;
  color: var(--c-primary);
  transition: all var(--transition-base);
}

.card:hover .card-icon {
  background: linear-gradient(135deg, var(--c-primary), #2563eb);
  color: #fff;
  box-shadow: 0 4px 14px rgba(53,133,255,.3);
}

.card-icon svg {
  width: 24px;
  height: 24px;
}

.card h3 {
  margin-bottom: 10px;
  font-size: 1.05rem;
  font-weight: 700;
}

.card p {
  font-size: .9rem;
  color: var(--c-text-light);
  margin-bottom: 0;
  line-height: 1.7;
}

/* ---------- Animations ---------- */
@keyframes fadeInUp {
  from { opacity: 0; transform: translateY(36px); }
  to   { opacity: 1; transform: translateY(0); }
}

@keyframes float {
  0%, 100% { transform: translateY(0); }
  50%      { transform: translateY(-12px); }
}

@keyframes pulse-glow {
  0%, 100% { opacity: .5; }
  50%      { opacity: 1; }
}

@keyframes gradient-shift {
  0%   { background-position: 0% 50%; }
  50%  { background-position: 100% 50%; }
  100% { background-position: 0% 50%; }
}

@keyframes marquee {
  0%   { transform: translateX(0); }
  100% { transform: translateX(-50%); }
}

.animate-on-scroll {
  opacity: 0;
  transform: translateY(36px);
  transition: opacity .7s cubic-bezier(.4,0,.2,1), transform .7s cubic-bezier(.4,0,.2,1);
}

.animate-on-scroll.visible {
  opacity: 1;
  transform: translateY(0);
}

/* Stagger delay classes */
.delay-1 { transition-delay: .08s; }
.delay-2 { transition-delay: .16s; }
.delay-3 { transition-delay: .24s; }
.delay-4 { transition-delay: .32s; }
.delay-5 { transition-delay: .40s; }
.delay-6 { transition-delay: .48s; }
.delay-7 { transition-delay: .56s; }
.delay-8 { transition-delay: .64s; }
.delay-9 { transition-delay: .72s; }
.delay-10 { transition-delay: .80s; }
.delay-11 { transition-delay: .88s; }
.delay-12 { transition-delay: .96s; }

/* ---------- Responsive ---------- */
@media (max-width: 992px) {
  h1 { font-size: 2.4rem; }
  h2 { font-size: 1.75rem; }
  .grid-4 { grid-template-columns: repeat(2, 1fr); }
  .grid-3 { grid-template-columns: repeat(2, 1fr); }
  .section { padding: 72px 0; }
}

@media (max-width: 768px) {
  h1 { font-size: 1.9rem; }
  h2 { font-size: 1.5rem; }
  .grid-2 { grid-template-columns: 1fr; }
  .grid-3 { grid-template-columns: 1fr; }
  .grid-4 { grid-template-columns: 1fr; }
  .section { padding: 56px 0; }
  .container { padding: 0 18px; }
}

@media (max-width: 480px) {
  h1 { font-size: 1.55rem; }
}