/* ============================================================
   帮帮课堂助手 — 官方网站样式
   ============================================================ */

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

:root {
  --primary:       #6366F1;
  --primary-dark:  #4F46E5;
  --primary-light: #A5B4FC;
  --accent:        #8B5CF6;
  --cyan:          #06B6D4;
  --bg-dark:       #0F172A;
  --bg-darker:     #020617;
  --text-main:     #1E293B;
  --text-secondary:#64748B;
  --text-light:    #94A3B8;
  --white:         #FFFFFF;
  --card-bg:       #FFFFFF;
  --border:        #E2E8F0;
  --radius-sm:     8px;
  --radius:        12px;
  --radius-lg:     20px;
  --radius-xl:     28px;
  --shadow-sm:     0 1px 2px rgba(0,0,0,.05);
  --shadow:        0 4px 6px -1px rgba(0,0,0,.07), 0 2px 4px -2px rgba(0,0,0,.05);
  --shadow-lg:     0 20px 25px -5px rgba(0,0,0,.1), 0 8px 10px -6px rgba(0,0,0,.06);
  --shadow-xl:     0 25px 50px -12px rgba(0,0,0,.15);
  --transition:    0.3s cubic-bezier(.4,0,.2,1);
  --max-width:     1200px;
}

html {
  scroll-behavior: smooth;
  scroll-padding-top: 80px;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Microsoft YaHei", "Hiragino Sans GB", "WenQuanYi Micro Hei", "Helvetica Neue", Arial, sans-serif;
  color: var(--text-main);
  line-height: 1.6;
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
}

img, svg { display: block; max-width: 100%; }
a { text-decoration: none; color: inherit; }
ul { list-style: none; }

/* ---------- Utility ---------- */
.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 24px;
}

.text-gradient {
  background: linear-gradient(135deg, var(--primary), var(--accent));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.text-gradient-light {
  background: linear-gradient(135deg, #C4B5FD, #67E8F9);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.text-white { color: var(--white); }
.text-gray  { color: var(--text-light); }

/* ---------- Buttons ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 12px 28px;
  border-radius: 50px;
  font-weight: 600;
  font-size: 15px;
  cursor: pointer;
  transition: var(--transition);
  border: none;
  white-space: nowrap;
  font-family: inherit;
}

.btn-primary {
  background: linear-gradient(135deg, var(--primary), var(--accent));
  color: var(--white);
  box-shadow: 0 4px 15px rgba(99,102,241,.35);
}
.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 25px rgba(99,102,241,.45);
}

.btn-outline {
  background: transparent;
  color: var(--white);
  border: 2px solid rgba(255,255,255,.3);
}
.btn-outline:hover {
  background: rgba(255,255,255,.1);
  border-color: rgba(255,255,255,.5);
  transform: translateY(-2px);
}

.btn-sm { padding: 8px 20px; font-size: 14px; }
.btn-lg { padding: 16px 36px; font-size: 17px; }
.btn-block { width: 100%; justify-content: center; }

/* ---------- Header ---------- */
.header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 1000;
  background: rgba(15,23,42,.88);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  transition: var(--transition);
}

.header.scrolled {
  background: rgba(15,23,42,.95);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  box-shadow: 0 1px 3px rgba(0,0,0,.25);
}

.header .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 72px;
}

.logo {
  display: flex;
  align-items: center;
  gap: 10px;
  font-weight: 700;
  font-size: 18px;
  color: var(--white);
  z-index: 1001;
}

.logo-icon {
  width: 36px;
  height: 36px;
}

.nav-list {
  display: flex;
  gap: 8px;
}

.nav-link {
  padding: 8px 16px;
  border-radius: 8px;
  color: rgba(255,255,255,.75);
  font-weight: 500;
  font-size: 15px;
  transition: var(--transition);
}

.nav-link:hover {
  color: var(--white);
  background: rgba(255,255,255,.1);
}

.header-cta { z-index: 1001; }

.menu-toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  background: none;
  border: none;
  cursor: pointer;
  z-index: 1001;
  padding: 4px;
}

.menu-toggle span {
  display: block;
  width: 24px;
  height: 2px;
  background: var(--white);
  border-radius: 2px;
  transition: var(--transition);
}

.menu-toggle.active span:nth-child(1) { transform: rotate(45deg) translate(5px,5px); }
.menu-toggle.active span:nth-child(2) { opacity: 0; }
.menu-toggle.active span:nth-child(3) { transform: rotate(-45deg) translate(5px,-5px); }

/* ---------- Slideshow ---------- */
.slideshow {
  position: relative;
  margin-top: 72px;
  background: var(--bg-dark);
  overflow: hidden;
  min-height: 520px;
}

.slides-wrapper {
  position: relative;
  width: 100%;
  height: 100%;
}

.slide {
  position: absolute;
  top: 0; left: 0;
  width: 100%; height: 100%;
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.7s ease, transform 0.7s ease;
  transform: scale(1.03);
  padding: 60px 0;
  display: flex;
  align-items: center;
}

.slide.active {
  opacity: 1;
  pointer-events: auto;
  transform: scale(1);
  position: relative;
}

.slide-bg-orb {
  position: absolute;
  border-radius: 50%;
  filter: blur(100px);
  pointer-events: none;
  opacity: 0.2;
}

.slide-orb-l {
  width: 350px; height: 350px;
  background: var(--primary);
  top: -100px; left: -150px;
}

.slide-orb-r {
  width: 300px; height: 300px;
  background: var(--cyan);
  bottom: -100px; right: -100px;
}

.slide-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 50px;
  align-items: center;
  position: relative;
  z-index: 1;
}

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

.slide-tag {
  display: inline-block;
  padding: 5px 14px;
  background: rgba(99,102,241,.2);
  color: var(--primary-light);
  font-size: 12px;
  font-weight: 600;
  border-radius: 50px;
  margin-bottom: 20px;
  letter-spacing: 0.04em;
}

.slide-title {
  font-size: clamp(28px, 4vw, 46px);
  font-weight: 900;
  line-height: 1.2;
  margin-bottom: 20px;
}

.slide-desc {
  font-size: 16px;
  line-height: 1.8;
  color: var(--text-light);
  max-width: 460px;
  margin-bottom: 32px;
}

.slide-visual {
  display: flex;
  align-items: center;
  justify-content: center;
}

.slide-visual svg {
  width: 100%;
  max-width: 540px;
  height: auto;
  filter: drop-shadow(0 20px 40px rgba(0,0,0,.4));
}

/* Slide Arrows */
.slide-arrow {
  position: absolute;
  top: 50%;
  transform: translateY(-50%);
  width: 48px; height: 48px;
  border-radius: 50%;
  background: rgba(255,255,255,.08);
  border: 1px solid rgba(255,255,255,.15);
  color: var(--white);
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  z-index: 10;
  backdrop-filter: blur(10px);
  transition: var(--transition);
}

.slide-arrow:hover {
  background: rgba(255,255,255,.15);
  border-color: rgba(255,255,255,.3);
}

.slide-arrow svg {
  width: 24px; height: 24px;
}

.slide-prev { left: 24px; }
.slide-next { right: 24px; }

/* Slide Dots */
.slide-dots {
  position: absolute;
  bottom: 28px;
  left: 50%;
  transform: translateX(-50%);
  display: flex;
  gap: 10px;
  z-index: 10;
}

.slide-dot {
  width: 10px; height: 10px;
  border-radius: 50%;
  background: rgba(255,255,255,.3);
  border: none;
  cursor: pointer;
  transition: var(--transition);
  padding: 0;
}

.slide-dot:hover {
  background: rgba(255,255,255,.5);
}

.slide-dot.active {
  background: var(--white);
  box-shadow: 0 0 10px rgba(255,255,255,.4);
  width: 28px;
  border-radius: 10px;
}

/* ---------- Hero ---------- */
.hero {
  position: relative;
  background: var(--bg-dark);
  padding: 140px 0 80px;
  overflow: hidden;
}

.hero-bg-orb {
  position: absolute;
  border-radius: 50%;
  filter: blur(120px);
  opacity: 0.3;
  pointer-events: none;
}
.hero-orb-1 {
  width: 500px; height: 500px;
  background: var(--primary);
  top: -200px; right: -100px;
}
.hero-orb-2 {
  width: 400px; height: 400px;
  background: var(--accent);
  bottom: -100px; left: -100px;
  opacity: 0.2;
}
.hero-orb-3 {
  width: 300px; height: 300px;
  background: var(--cyan);
  top: 50%; left: 40%;
  opacity: 0.15;
}

.hero-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 60px;
  align-items: center;
  position: relative;
  z-index: 1;
}

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

.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  background: rgba(99,102,241,.2);
  border: 1px solid rgba(99,102,241,.3);
  padding: 8px 16px;
  border-radius: 50px;
  font-size: 13px;
  color: var(--primary-light);
  margin-bottom: 24px;
}

.hero-title {
  font-size: clamp(36px, 5vw, 60px);
  font-weight: 900;
  line-height: 1.15;
  letter-spacing: -0.02em;
  margin-bottom: 20px;
}

.hero-title-highlight {
  background: linear-gradient(135deg, var(--primary-light), var(--cyan));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.hero-desc {
  font-size: 18px;
  line-height: 1.7;
  color: var(--text-light);
  max-width: 520px;
  margin-bottom: 32px;
}

.hero-actions {
  display: flex;
  gap: 16px;
  flex-wrap: wrap;
  margin-bottom: 48px;
}

.hero-stats {
  display: flex;
  gap: 40px;
}
.hero-stat strong {
  display: block;
  font-size: 28px;
  font-weight: 800;
  color: var(--white);
}
.hero-stat span {
  font-size: 14px;
  color: var(--text-light);
}

/* Hero Visual */
.hero-visual {
  position: relative;
  display: flex;
  align-items: center;
  justify-content: center;
}

.hero-screen {
  position: relative;
  width: 100%;
  max-width: 460px;
  perspective: 1000px;
}

.hero-screen-inner {
  background: linear-gradient(135deg, #1E293B, #334155);
  border: 1px solid rgba(255,255,255,.1);
  border-radius: var(--radius-lg);
  overflow: hidden;
  box-shadow: 0 25px 50px -12px rgba(0,0,0,.4);
  transform: rotateY(-5deg) rotateX(3deg);
  transition: transform 0.5s ease;
}

.hero-screen-inner:hover {
  transform: rotateY(0deg) rotateX(0deg);
}

.hero-screen-dots {
  display: flex;
  gap: 8px;
  padding: 14px 18px;
  background: rgba(0,0,0,.3);
  border-bottom: 1px solid rgba(255,255,255,.05);
}
.hero-screen-dots span {
  width: 10px; height: 10px;
  border-radius: 50%;
  background: rgba(255,255,255,.3);
}
.hero-screen-dots span:nth-child(1) { background: #EF4444; }
.hero-screen-dots span:nth-child(2) { background: #F59E0B; }
.hero-screen-dots span:nth-child(3) { background: #10B981; }

.hero-screen-content {
  padding: 24px;
  background: rgba(255,255,255,.97);
  min-height: 280px;
  display: flex;
  align-items: center;
  justify-content: center;
}

.hero-demo-slide h3 {
  text-align: center;
  font-size: 18px;
  color: var(--text-main);
  margin-bottom: 16px;
}

.hero-demo-annotation {
  width: 100%;
  height: auto;
}

.hero-screen-shadow {
  position: absolute;
  bottom: -20px;
  left: 10%;
  right: 10%;
  height: 30px;
  background: radial-gradient(ellipse, rgba(99,102,241,.5), transparent);
  filter: blur(15px);
}

.hero-float-card {
  position: absolute;
  display: flex;
  align-items: center;
  gap: 8px;
  background: rgba(255,255,255,.95);
  backdrop-filter: blur(10px);
  padding: 10px 18px;
  border-radius: 50px;
  font-size: 13px;
  font-weight: 600;
  color: var(--text-main);
  box-shadow: var(--shadow-lg);
  animation: float 3s ease-in-out infinite;
}

.hero-float-1 { top: 10%; left: -30px; animation-delay: 0s; }
.hero-float-2 { bottom: 15%; right: -20px; animation-delay: 1.5s; }

.float-dot {
  width: 8px; height: 8px;
  border-radius: 50%;
  background: var(--dot);
}

/* Hero toolbar mock */
.hero-toolbar-mock {
  display: flex;
  gap: 10px;
  flex-wrap: wrap;
  justify-content: center;
  padding: 8px;
}

.tb-icon {
  width: 42px; height: 42px;
  border-radius: var(--radius-sm);
  background: var(--tb-bg);
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: 0 3px 10px rgba(0,0,0,.15);
  transition: transform 0.2s ease;
}

.tb-icon:hover {
  transform: scale(1.15);
}

.tb-icon svg {
  width: 20px; height: 20px;
}

@keyframes float {
  0%,100% { transform: translateY(0); }
  50%      { transform: translateY(-10px); }
}

.hero-wave {
  position: absolute;
  bottom: -1px;
  left: 0; right: 0;
  line-height: 0;
}

/* ---------- Sections Common ---------- */
.section-header {
  text-align: center;
  max-width: 640px;
  margin: 0 auto 60px;
}

.section-tag {
  display: inline-block;
  padding: 6px 16px;
  background: rgba(99,102,241,.1);
  color: var(--primary);
  font-weight: 600;
  font-size: 13px;
  border-radius: 50px;
  margin-bottom: 16px;
  letter-spacing: 0.02em;
}

.section-tag-light {
  background: rgba(255,255,255,.15);
  color: var(--primary-light);
}

.section-title {
  font-size: clamp(28px, 4vw, 42px);
  font-weight: 800;
  letter-spacing: -0.02em;
  margin-bottom: 16px;
  line-height: 1.25;
}

.section-desc {
  font-size: 17px;
  color: var(--text-secondary);
  line-height: 1.7;
}

/* ---------- Features ---------- */
.features {
  padding: 100px 0;
  background: var(--white);
}

.features-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 20px;
}

.feature-card {
  padding: 32px 28px;
  border-radius: var(--radius-lg);
  background: var(--white);
  border: 1px solid var(--border);
  transition: var(--transition);
}

.feature-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-lg);
  border-color: transparent;
}

.feature-icon {
  width: 52px; height: 52px;
  border-radius: var(--radius);
  background: var(--icon-bg);
  color: var(--icon-color);
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 20px;
}

.feature-icon svg {
  width: 26px; height: 26px;
}

.feature-card h3 {
  font-size: 18px;
  font-weight: 700;
  margin-bottom: 10px;
}

.feature-card p {
  font-size: 14px;
  color: var(--text-secondary);
  line-height: 1.7;
}

/* ---------- Use Cases ---------- */
.usecases {
  padding: 100px 0;
  background: #F8FAFC;
}

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

.usecase-card {
  background: var(--white);
  border-radius: var(--radius-lg);
  padding: 32px 28px;
  border: 1px solid var(--border);
  transition: var(--transition);
  text-align: center;
}

.usecase-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-lg);
}

.usecase-img {
  width: 100%;
  margin-bottom: 24px;
  display: flex;
  align-items: center;
  justify-content: center;
}

.usecase-img svg {
  width: 100%;
  max-width: 240px;
  height: auto;
}

.usecase-card h3 {
  font-size: 18px;
  font-weight: 700;
  margin-bottom: 10px;
}

.usecase-card p {
  font-size: 14px;
  color: var(--text-secondary);
  line-height: 1.7;
}

/* ---------- Gallery ---------- */
.gallery {
  padding: 100px 0;
  background: var(--white);
}

.gallery-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 24px;
}

.gallery-card {
  border-radius: var(--radius-lg);
  overflow: hidden;
  border: 1px solid var(--border);
  transition: var(--transition);
}

.gallery-card:hover {
  box-shadow: var(--shadow-xl);
  transform: translateY(-2px);
}

.gallery-placeholder svg {
  width: 100%;
  height: auto;
}

.gallery-card p {
  text-align: center;
  padding: 16px;
  font-size: 14px;
  color: var(--text-secondary);
  font-weight: 500;
}

/* ---------- Testimonials ---------- */
.testimonials {
  padding: 100px 0;
  background: #F8FAFC;
}

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

.testimonial-card {
  background: var(--white);
  padding: 28px;
  border-radius: var(--radius-lg);
  border: 1px solid var(--border);
  transition: var(--transition);
}

.testimonial-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-lg);
}

.testimonial-stars {
  color: #F59E0B;
  font-size: 18px;
  letter-spacing: 2px;
  margin-bottom: 16px;
}

.testimonial-text {
  font-size: 15px;
  line-height: 1.7;
  color: var(--text-main);
  margin-bottom: 20px;
  font-style: italic;
}

.testimonial-author {
  display: flex;
  align-items: center;
  gap: 12px;
}

.testimonial-avatar {
  width: 44px; height: 44px;
  border-radius: 50%;
  background: var(--avatar-bg);
  color: #fff;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  font-size: 16px;
  flex-shrink: 0;
}

.testimonial-author strong {
  display: block;
  font-size: 14px;
  font-weight: 600;
}

.testimonial-author span {
  font-size: 13px;
  color: var(--text-secondary);
}

/* ---------- Download ---------- */
.download {
  position: relative;
  padding: 100px 0;
  background: var(--bg-dark);
  overflow: hidden;
}

.download-bg-orb {
  position: absolute;
  border-radius: 50%;
  filter: blur(120px);
  pointer-events: none;
}

.download-orb-1 {
  width: 400px; height: 400px;
  background: var(--primary);
  top: -100px; left: -100px;
  opacity: 0.25;
}

.download-orb-2 {
  width: 350px; height: 350px;
  background: var(--accent);
  bottom: -100px; right: -100px;
  opacity: 0.2;
}

.download .container { position: relative; z-index: 1; }

.download-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 20px;
  max-width: 900px;
  margin: 0 auto 32px;
}

.download-card {
  position: relative;
  background: rgba(255,255,255,.05);
  backdrop-filter: blur(10px);
  border: 1px solid rgba(255,255,255,.1);
  border-radius: var(--radius-lg);
  padding: 36px 28px;
  text-align: center;
  color: var(--white);
  transition: var(--transition);
}

.download-card:hover {
  transform: translateY(-4px);
  border-color: rgba(255,255,255,.2);
  background: rgba(255,255,255,.08);
}

.download-card-badge {
  position: absolute;
  top: -12px; right: 20px;
  background: linear-gradient(135deg, var(--primary), var(--accent));
  color: #fff;
  font-size: 12px;
  font-weight: 700;
  padding: 4px 14px;
  border-radius: 50px;
  box-shadow: 0 4px 12px rgba(99,102,241,.4);
}

.download-card-soon {
  opacity: 0.7;
}
.download-card-soon:hover {
  opacity: 0.9;
}

.btn-disabled {
  cursor: not-allowed;
  opacity: 0.6;
  pointer-events: none;
}

.download-os-icon {
  width: 56px; height: 56px;
  margin: 0 auto 20px;
}

.download-card h3 {
  font-size: 20px;
  font-weight: 700;
  margin-bottom: 6px;
}

.download-card p.download-card-desc {
  font-size: 13px;
  color: var(--text-light);
  margin-bottom: 20px;
  line-height: 1.7;
}

.download-card p {
  font-size: 14px;
  color: var(--text-light);
  margin-bottom: 24px;
}

.download-card small {
  display: block;
  margin-top: 12px;
  font-size: 12px;
  color: var(--text-light);
}

.download-note {
  text-align: center;
  color: var(--text-light);
  font-size: 14px;
}

.download-note strong { color: var(--white); }
.download-note a { color: var(--primary-light); text-decoration: underline; }

/* ---------- Contact ---------- */
.contact {
  padding: 100px 0;
  background: var(--white);
}

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

.contact-card {
  padding: 32px 28px;
  border-radius: var(--radius-lg);
  background: var(--white);
  border: 1px solid var(--border);
  transition: var(--transition);
  text-align: center;
}

.contact-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-lg);
}

.contact-icon {
  width: 56px; height: 56px;
  border-radius: var(--radius);
  background: var(--icon-bg);
  color: var(--icon-color);
  display: flex;
  align-items: center;
  justify-content: center;
  margin: 0 auto 20px;
}

.contact-icon svg {
  width: 28px; height: 28px;
}

.contact-card h3 {
  font-size: 18px;
  font-weight: 700;
  margin-bottom: 12px;
}

.contact-value {
  display: inline-block;
  font-size: 20px;
  font-weight: 700;
  color: var(--primary);
  margin-bottom: 12px;
  transition: var(--transition);
}

.contact-value:hover {
  color: var(--accent);
}

.contact-card p {
  font-size: 14px;
  color: var(--text-secondary);
  line-height: 1.7;
}

/* ---------- Footer ---------- */
.mobile-br { display: none; }

@media (max-width: 420px) {
  .mobile-br { display: block; }
}
.footer {
  background: var(--bg-darker);
  color: var(--text-light);
  padding: 60px 0 30px;
}

.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: 40px;
  margin-bottom: 40px;
}

.footer-brand .logo {
  margin-bottom: 16px;
}

.footer-brand p {
  font-size: 14px;
  line-height: 1.7;
  max-width: 280px;
  color: var(--text-light);
}

.footer-links h4 {
  color: var(--white);
  font-size: 14px;
  font-weight: 600;
  margin-bottom: 16px;
}

.footer-links ul {
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.footer-links a {
  font-size: 14px;
  transition: var(--transition);
}

.footer-links a:hover {
  color: var(--white);
}

.footer-bottom {
  border-top: 1px solid rgba(255,255,255,.08);
  padding-top: 24px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-size: 13px;
  flex-wrap: wrap;
  gap: 8px;
}

/* ---------- Animations ---------- */
[data-animate] {
  opacity: 0;
  transform: translateY(30px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}

[data-animate].visible {
  opacity: 1;
  transform: translateY(0);
}

/* ============================================================
   RESPONSIVE
   ============================================================ */

/* Tablet / Small Desktop */
@media (max-width: 860px) {
  .slideshow {
    min-height: auto;
  }
  .slide-grid {
    grid-template-columns: 1fr;
    text-align: center;
    gap: 30px;
  }
  .slide-desc {
    max-width: 100%;
    margin-left: auto;
    margin-right: auto;
  }
  .slide-visual {
    max-width: 400px;
    margin: 0 auto;
  }
  .slide-arrow {
    width: 38px; height: 38px;
  }
  .slide-prev { left: 12px; }
  .slide-next { right: 12px; }

  .hero-grid {
    grid-template-columns: 1fr;
    text-align: center;
  }

  .hero-desc {
    max-width: 100%;
    margin-left: auto;
    margin-right: auto;
  }

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

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

  .hero-visual {
    max-width: 420px;
    margin: 0 auto;
  }

  .hero-float-card {
    display: none;
  }

  .features-grid {
    grid-template-columns: repeat(2, 1fr);
  }

  .usecases-grid {
    grid-template-columns: repeat(2, 1fr);
  }

  .contact-grid {
    grid-template-columns: repeat(2, 1fr);
  }

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

  .testimonials-grid {
    grid-template-columns: repeat(2, 1fr);
  }

  .footer-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

/* Mobile */
@media (max-width: 640px) {

  /* Mobile Nav — right drawer */
  .nav-overlay {
    position: fixed;
    inset: 0;
    background: rgba(0,0,0,.5);
    opacity: 0;
    pointer-events: none;
    transition: opacity 0.3s ease;
    z-index: 998;
  }

  .nav-overlay.active {
    opacity: 1;
    pointer-events: auto;
  }

  .nav {
    position: fixed;
    top: 0; right: 0; bottom: 0;
    width: 280px;
    background: rgba(15,23,42,.98);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    display: flex;
    align-items: flex-start;
    justify-content: center;
    padding: 100px 28px 28px;
    transform: translateX(100%);
    transition: transform 0.35s cubic-bezier(.4,0,.2,1);
    z-index: 999;
    border-left: 1px solid rgba(255,255,255,.06);
  }

  .nav.active {
    transform: translateX(0);
  }

  .nav-list {
    flex-direction: column;
    align-items: flex-start;
    width: 100%;
    gap: 4px;
  }

  .nav-link {
    font-size: 17px;
    padding: 14px 16px;
    display: block;
    width: 100%;
    border-radius: 10px;
  }

  .header-cta {
    display: none;
  }

  .menu-toggle {
    display: flex;
  }

  .header .container {
    height: 64px;
  }

  /* Slideshow */
  .slideshow {
    margin-top: 64px;
    min-height: auto;
  }

  .slide {
    padding: 40px 0;
  }

  .slide-title {
    font-size: 24px;
  }

  .slide-desc {
    font-size: 14px;
  }

  .slide-visual {
    max-width: 320px;
    margin: 0 auto;
  }

  .slide-arrow {
    display: none;
  }

  /* Hero */
  .hero {
    padding: 100px 0 60px;
  }

  .hero-title {
    font-size: 32px;
  }

  .hero-desc {
    font-size: 16px;
  }

  .hero-actions {
    flex-direction: column;
    align-items: center;
  }

  .hero-stats {
    gap: 24px;
    flex-wrap: wrap;
  }

  .hero-visual {
    max-width: 320px;
  }

  /* Grids */
  .features-grid,
  .usecases-grid,
  .testimonials-grid,
  .contact-grid {
    grid-template-columns: 1fr;
  }

  .download-grid {
    grid-template-columns: 1fr;
    max-width: 400px;
  }

  .footer-grid {
    grid-template-columns: 1fr;
    gap: 32px;
  }

  .footer-bottom {
    flex-direction: column;
    text-align: center;
  }

  .section-title {
    font-size: 28px;
  }

  .features,
  .usecases,
  .gallery,
  .testimonials,
  .download {
    padding: 70px 0;
  }
}

/* Small Mobile */
@media (max-width: 420px) {
  .container {
    padding: 0 16px;
  }

  .hero {
    padding: 80px 0 50px;
  }

  .hero-title {
    font-size: 28px;
  }

  .hero-stats {
    gap: 16px;
  }

  .hero-stat strong {
    font-size: 22px;
  }

  .hero-float-card {
    display: none;
  }

  .btn-lg {
    padding: 14px 28px;
    font-size: 15px;
  }
}