/* ==========================================================================
   FLAI Official Website - style.css
   Pure CSS3 + CSS Custom Properties (Design Tokens)
   ========================================================================== */

/* ===== Design Tokens ===== */
:root {
  /* -- Color Palette -- */
  --color-primary: #08c955;
  --color-primary-dark: #069a3f;
  --color-primary-light: #4ad97e;
  --color-primary-lighter: #e6f9ee;
  --color-accent: #635bff;
  --color-accent-dark: #4a44e0;
  --color-accent-light: #8b85ff;
  --color-bg: #f8f8f8;
  --color-bg-alt: #ffffff;
  --color-surface: #ffffff;
  --color-text: #1a1a2e;
  --color-text-secondary: #6b6b80;
  --color-text-muted: #a0a0b5;
  --color-border: #e8e8e8;
  --color-border-light: #f0f0f0;
  --color-gradient-start: #08c955;
  --color-gradient-end: #00d4aa;
  --color-danger: #ff4757;
  --color-warning: #ffa502;
  --color-success: #08c955;

  /* -- Typography -- */
  --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI",
    "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei",
    "Helvetica Neue", sans-serif;
  --font-mono: "JetBrains Mono", "Fira Code", "SF Mono",
    "Courier New", monospace;
  --fs-xs: 0.75rem;
  --fs-sm: 0.875rem;
  --fs-base: 1rem;
  --fs-lg: 1.125rem;
  --fs-xl: 1.375rem;
  --fs-2xl: 1.75rem;
  --fs-3xl: 2.5rem;
  --fs-4xl: 3.5rem;

  /* -- Spacing -- */
  --space-xs: 4px;
  --space-sm: 8px;
  --space-md: 16px;
  --space-lg: 24px;
  --space-xl: 48px;
  --space-2xl: 80px;
  --space-3xl: 120px;

  /* -- Radius -- */
  --radius-sm: 8px;
  --radius-md: 12px;
  --radius-lg: 20px;
  --radius-xl: 32px;
  --radius-full: 999px;

  /* -- Shadow -- */
  --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.06);
  --shadow-md: 0 4px 16px rgba(0, 0, 0, 0.08);
  --shadow-lg: 0 8px 40px rgba(0, 0, 0, 0.10);
  --shadow-primary: 0 4px 20px rgba(8, 201, 85, 0.25);

  /* -- Transition -- */
  --transition-fast: 150ms ease;
  --transition-base: 250ms ease;
  --transition-slow: 400ms ease;

  /* -- Layout -- */
  --container-max: 1200px;
  --container-padding: 24px;
  --nav-height: 64px;
}

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

html {
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
  scroll-padding-top: var(--nav-height);
}

body {
  font-family: var(--font-sans);
  font-size: var(--fs-base);
  line-height: 1.7;
  color: var(--color-text);
  background-color: var(--color-bg);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  overflow-x: hidden;
}

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

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

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

ul, ol {
  list-style: none;
}

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

/* ===== Utility ===== */
.container {
  width: 100%;
  max-width: var(--container-max);
  margin: 0 auto;
  padding: 0 var(--container-padding);
}

.text-center { text-align: center; }
.text-gradient {
  background: linear-gradient(135deg, var(--color-gradient-start), var(--color-gradient-end));
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
}

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

/* ===== Section ===== */
.section {
  padding: var(--space-2xl) 0;
}

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

.section-header {
  text-align: center;
  margin-bottom: var(--space-xl);
}

.section-header h2 {
  font-size: var(--fs-2xl);
  font-weight: 700;
  margin-bottom: var(--space-md);
  letter-spacing: -0.02em;
}

.section-header p {
  font-size: var(--fs-lg);
  color: var(--color-text-secondary);
  max-width: 640px;
  margin: 0 auto;
}

.section-tag {
  display: inline-block;
  padding: 4px 16px;
  background: var(--color-primary-lighter);
  color: var(--color-primary-dark);
  border-radius: var(--radius-full);
  font-size: var(--fs-sm);
  font-weight: 600;
  margin-bottom: var(--space-md);
}

/* ===== Buttons ===== */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-sm);
  padding: 12px 32px;
  border-radius: var(--radius-full);
  font-size: var(--fs-base);
  font-weight: 600;
  transition: all var(--transition-base);
  white-space: nowrap;
  cursor: pointer;
}

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

.btn--primary:hover {
  background: var(--color-primary-dark);
  color: #fff;
  transform: translateY(-2px);
  box-shadow: 0 6px 24px rgba(8, 201, 85, 0.35);
}

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

.btn--secondary:hover {
  border-color: var(--color-primary);
  color: var(--color-primary);
  transform: translateY(-2px);
}

.btn--ghost {
  background: transparent;
  color: var(--color-text);
  padding: 8px 20px;
}

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

.btn--lg {
  padding: 16px 40px;
  font-size: var(--fs-lg);
}

.btn--block {
  width: 100%;
}

.btn i {
  font-size: 1.2em;
}

/* ===== Navigation ===== */
.nav {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: var(--nav-height);
  z-index: 1000;
  transition: all var(--transition-base);
  background: transparent;
}

.nav--scrolled {
  background: rgba(255, 255, 255, 0.92);
  backdrop-filter: saturate(180%) blur(20px);
  -webkit-backdrop-filter: saturate(180%) blur(20px);
  box-shadow: var(--shadow-sm);
}

.nav__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 100%;
}

.nav__logo {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  font-size: var(--fs-xl);
  font-weight: 800;
  color: var(--color-text);
  letter-spacing: -0.03em;
}

.nav__logo:hover {
  color: var(--color-text);
}

.nav__logo-img {
  width: 32px;
  height: 32px;
  border-radius: var(--radius-sm);
  flex-shrink: 0;
}

.nav__links {
  display: none;
  align-items: center;
  gap: var(--space-lg);
}

.nav__links a {
  color: var(--color-text-secondary);
  font-size: var(--fs-sm);
  font-weight: 500;
  transition: color var(--transition-fast);
}

.nav__links a:hover {
  color: var(--color-primary);
}

.nav__actions {
  display: flex;
  align-items: center;
  gap: var(--space-md);
}

.nav__toggle {
  display: flex;
  flex-direction: column;
  gap: 5px;
  padding: 8px;
}

.nav__toggle span {
  width: 24px;
  height: 2px;
  background: var(--color-text);
  border-radius: 2px;
  transition: all var(--transition-base);
}

.nav__toggle--open span:nth-child(1) {
  transform: translateY(7px) rotate(45deg);
}

.nav__toggle--open span:nth-child(2) {
  opacity: 0;
}

.nav__toggle--open span:nth-child(3) {
  transform: translateY(-7px) rotate(-45deg);
}

/* Mobile menu */
.nav__mobile {
  position: fixed;
  top: var(--nav-height);
  left: 0;
  right: 0;
  background: var(--color-surface);
  box-shadow: var(--shadow-md);
  padding: var(--space-lg) var(--container-padding);
  display: flex;
  flex-direction: column;
  gap: var(--space-md);
  transform: translateY(-100%);
  opacity: 0;
  pointer-events: none;
  transition: all var(--transition-base);
}

.nav__mobile--open {
  transform: translateY(0);
  opacity: 1;
  pointer-events: auto;
}

.nav__mobile a {
  color: var(--color-text);
  font-size: var(--fs-base);
  font-weight: 500;
  padding: var(--space-sm) 0;
  border-bottom: 1px solid var(--color-border-light);
}

.nav__mobile a:hover {
  color: var(--color-primary);
}

/* ===== Hero ===== */
.hero {
  position: relative;
  min-height: 100vh;
  display: flex;
  align-items: center;
  padding-top: var(--nav-height);
  overflow: hidden;
  background: linear-gradient(160deg, var(--color-primary-lighter) 0%, var(--color-bg) 50%);
}

.hero::before {
  content: "";
  position: absolute;
  top: -20%;
  right: -10%;
  width: 600px;
  height: 600px;
  background: radial-gradient(circle, rgba(8, 201, 85, 0.08) 0%, transparent 70%);
  border-radius: 50%;
  pointer-events: none;
}

.hero::after {
  content: "";
  position: absolute;
  bottom: -20%;
  left: -10%;
  width: 500px;
  height: 500px;
  background: radial-gradient(circle, rgba(99, 91, 255, 0.06) 0%, transparent 70%);
  border-radius: 50%;
  pointer-events: none;
}

.hero__inner {
  position: relative;
  z-index: 1;
  display: grid;
  gap: var(--space-2xl);
  align-items: center;
}

.hero__badge {
  display: inline-flex;
  align-items: center;
  gap: var(--space-sm);
  padding: 6px 16px;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-full);
  font-size: var(--fs-sm);
  color: var(--color-text-secondary);
  box-shadow: var(--shadow-sm);
  margin-bottom: var(--space-lg);
}

.hero__badge i {
  color: var(--color-primary);
  font-size: 16px;
}

.hero__title {
  font-size: var(--fs-3xl);
  font-weight: 800;
  line-height: 1.2;
  letter-spacing: -0.03em;
  margin-bottom: var(--space-lg);
}

.hero__subtitle {
  font-size: var(--fs-lg);
  color: var(--color-text-secondary);
  margin-bottom: var(--space-xl);
  max-width: 520px;
}

.hero__cta {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-md);
  margin-bottom: var(--space-lg);
}

.hero__trust {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-lg);
  font-size: var(--fs-sm);
  color: var(--color-text-muted);
}

.hero__trust-item {
  display: flex;
  align-items: center;
  gap: var(--space-xs);
}

.hero__trust-item i {
  color: var(--color-primary);
  font-size: 18px;
}

/* Hero Image */
.hero__visual {
  display: flex;
  justify-content: center;
}

.hero__image-wrap {
  position: relative;
  display: inline-block;
}

.hero__img {
  width: auto;
  max-height: 560px;
  border-radius: var(--radius-xl);
  box-shadow: var(--shadow-lg);
  display: block;
}

/* Floating badges around phone */
.phone-badge {
  position: absolute;
  background: var(--color-surface);
  border-radius: var(--radius-lg);
  padding: var(--space-sm) var(--space-md);
  box-shadow: var(--shadow-md);
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  z-index: 10;
  animation: float 3s ease-in-out infinite;
}

.phone-badge__icon {
  width: 32px;
  height: 32px;
  border-radius: var(--radius-sm);
  display: flex;
  align-items: center;
  justify-content: center;
  color: #fff;
  font-size: 16px;
  flex-shrink: 0;
}

.phone-badge__text strong {
  font-size: var(--fs-sm);
  display: block;
}

.phone-badge__text span {
  font-size: var(--fs-xs);
  color: var(--color-text-muted);
}

.phone-badge--1 {
  top: 15%;
  left: -40px;
  animation: float 3s ease-in-out infinite;
}

.phone-badge--2 {
  top: 45%;
  right: -50px;
  animation: float 3s ease-in-out infinite 0.5s;
}

.phone-badge--3 {
  bottom: 15%;
  left: -30px;
  animation: float 3s ease-in-out infinite 1s;
}

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

.phone-badge i {
  font-size: 20px;
}

/* ===== Features ===== */
.features__grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--space-lg);
}

.feature-card {
  background: var(--color-surface);
  border-radius: var(--radius-lg);
  padding: var(--space-xl) var(--space-lg);
  box-shadow: var(--shadow-sm);
  transition: all var(--transition-base);
  border: 1px solid transparent;
}

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

.feature-card__icon {
  width: 56px;
  height: 56px;
  border-radius: var(--radius-md);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 28px;
  margin-bottom: var(--space-lg);
}

.feature-card__icon--1 {
  background: linear-gradient(135deg, rgba(8,201,85,0.12), rgba(8,201,85,0.04));
  color: var(--color-primary);
}

.feature-card__icon--2 {
  background: linear-gradient(135deg, rgba(99,91,255,0.12), rgba(99,91,255,0.04));
  color: var(--color-accent);
}

.feature-card__icon--3 {
  background: linear-gradient(135deg, rgba(0,212,170,0.12), rgba(0,212,170,0.04));
  color: #00d4aa;
}

.feature-card h3 {
  font-size: var(--fs-xl);
  font-weight: 700;
  margin-bottom: var(--space-sm);
}

.feature-card p {
  color: var(--color-text-secondary);
  font-size: var(--fs-base);
}

/* ===== Character Gallery ===== */
.chars__scroll {
  display: flex;
  gap: var(--space-md);
  overflow-x: auto;
  padding: var(--space-md) var(--space-xl) var(--space-lg);
  scroll-snap-type: x mandatory;
  -webkit-overflow-scrolling: touch;
  scrollbar-width: thin;
  scrollbar-color: var(--color-border) transparent;
}

.chars__scroll::-webkit-scrollbar {
  height: 6px;
}

.chars__scroll::-webkit-scrollbar-track {
  background: transparent;
}

.chars__scroll::-webkit-scrollbar-thumb {
  background: var(--color-border);
  border-radius: 3px;
}

.chars__scroll::-webkit-scrollbar-thumb:hover {
  background: var(--color-text-muted);
}

.char-card {
  flex: 0 0 200px;
  background: var(--color-surface);
  border-radius: var(--radius-lg);
  overflow: hidden;
  box-shadow: var(--shadow-sm);
  transition: all var(--transition-base);
  scroll-snap-align: start;
  cursor: pointer;
}

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

.char-card__avatar {
  width: 100%;
  aspect-ratio: 1;
  overflow: hidden;
  position: relative;
}

.char-card__avatar img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  display: block;
}

.char-card__tag {
  position: absolute;
  top: var(--space-sm);
  right: var(--space-sm);
  padding: 2px 10px;
  background: rgba(255, 255, 255, 0.9);
  border-radius: var(--radius-full);
  font-size: var(--fs-xs);
  font-weight: 600;
  color: var(--color-text);
}

.char-card__body {
  padding: var(--space-md);
}

.char-card__body h4 {
  font-size: var(--fs-base);
  font-weight: 700;
  margin-bottom: var(--space-xs);
}

.char-card__body p {
  font-size: var(--fs-sm);
  color: var(--color-text-secondary);
  line-height: 1.5;
}

.char-card__meta {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  margin-top: var(--space-sm);
  font-size: var(--fs-xs);
  color: var(--color-text-muted);
}

.char-card__meta i {
  font-size: 14px;
}

/* ===== App Screenshots ===== */
.screenshots {
  padding: var(--space-3xl) 0;
  background: var(--color-surface);
  overflow: hidden;
}

.screenshots__scroll {
  display: flex;
  gap: var(--space-lg);
  padding: var(--space-md) var(--space-xl);
  overflow-x: auto;
  scroll-snap-type: x mandatory;
  -webkit-overflow-scrolling: touch;
  scrollbar-width: thin;
}

.screenshots__scroll::-webkit-scrollbar {
  height: 6px;
}

.screenshots__scroll::-webkit-scrollbar-track {
  background: transparent;
}

.screenshots__scroll::-webkit-scrollbar-thumb {
  background: var(--color-border);
  border-radius: 3px;
}

.screenshot-card {
  flex: 0 0 auto;
  width: 280px;
  scroll-snap-align: center;
  border-radius: var(--radius-lg);
  overflow: hidden;
  box-shadow: var(--shadow-sm);
  transition: transform 0.3s ease, box-shadow 0.3s ease;
}

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

.screenshot-card img {
  width: 100%;
  height: auto;
  display: block;
}

/* ===== Advanced Features ===== */
.adv__item {
  display: grid;
  gap: var(--space-xl);
  align-items: center;
  margin-bottom: var(--space-2xl);
}

.adv__item:last-child {
  margin-bottom: 0;
}

.adv__visual {
  border-radius: var(--radius-lg);
  padding: var(--space-2xl) var(--space-xl);
  display: flex;
  align-items: center;
  justify-content: center;
  min-height: 280px;
  position: relative;
  overflow: hidden;
}

.adv__visual--1 {
  background: linear-gradient(135deg, var(--color-primary-lighter), #e0f7ee);
}

.adv__visual--2 {
  background: linear-gradient(135deg, #f0f0ff, #e8e5ff);
}

.adv__visual--3 {
  background: linear-gradient(135deg, #e0fcf5, #e6f9ee);
}

.adv__visual-icon {
  font-size: 80px;
  position: relative;
  z-index: 1;
}

.adv__visual::before {
  content: "";
  position: absolute;
  width: 200px;
  height: 200px;
  border-radius: 50%;
  background: rgba(255, 255, 255, 0.4);
  filter: blur(40px);
}

.adv__content h3 {
  font-size: var(--fs-2xl);
  font-weight: 700;
  margin-bottom: var(--space-md);
  letter-spacing: -0.02em;
}

.adv__content p {
  color: var(--color-text-secondary);
  font-size: var(--fs-lg);
  margin-bottom: var(--space-lg);
}

.adv__list {
  display: flex;
  flex-direction: column;
  gap: var(--space-sm);
}

.adv__list-item {
  display: flex;
  align-items: flex-start;
  gap: var(--space-sm);
  font-size: var(--fs-base);
  color: var(--color-text-secondary);
}

.adv__list-item i {
  color: var(--color-primary);
  font-size: 20px;
  flex-shrink: 0;
  margin-top: 2px;
}

/* ===== Scenarios ===== */
.scenarios__grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--space-md);
}

.scenario-card {
  background: var(--color-surface);
  border-radius: var(--radius-lg);
  padding: var(--space-lg);
  box-shadow: var(--shadow-sm);
  transition: all var(--transition-base);
  text-align: center;
}

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

.scenario-card__icon {
  width: 64px;
  height: 64px;
  margin: 0 auto var(--space-md);
  border-radius: var(--radius-md);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 32px;
  background: var(--color-primary-lighter);
  color: var(--color-primary);
}

.scenario-card h4 {
  font-size: var(--fs-lg);
  font-weight: 700;
  margin-bottom: var(--space-sm);
}

.scenario-card p {
  font-size: var(--fs-sm);
  color: var(--color-text-secondary);
}

/* ===== Download ===== */
.download {
  background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-gradient-end) 100%);
  border-radius: var(--radius-xl);
  padding: var(--space-2xl) var(--space-xl);
  text-align: center;
  color: #fff;
  position: relative;
  overflow: hidden;
}

.download::before {
  content: "";
  position: absolute;
  top: -50%;
  right: -10%;
  width: 400px;
  height: 400px;
  background: rgba(255, 255, 255, 0.06);
  border-radius: 50%;
}

.download::after {
  content: "";
  position: absolute;
  bottom: -30%;
  left: -5%;
  width: 300px;
  height: 300px;
  background: rgba(255, 255, 255, 0.04);
  border-radius: 50%;
}

.download__inner {
  position: relative;
  z-index: 1;
}

.download h2 {
  font-size: var(--fs-2xl);
  font-weight: 800;
  margin-bottom: var(--space-md);
}

.download p {
  font-size: var(--fs-lg);
  opacity: 0.9;
  margin-bottom: var(--space-xl);
}

.download__buttons {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: var(--space-md);
  margin-bottom: var(--space-lg);
}

.download__btn {
  display: inline-flex;
  align-items: center;
  gap: var(--space-sm);
  padding: 14px 32px;
  background: #fff;
  color: var(--color-text);
  border-radius: var(--radius-full);
  font-weight: 600;
  transition: all var(--transition-base);
}

.download__btn:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 24px rgba(0, 0, 0, 0.15);
  color: var(--color-text);
}

.download__btn i {
  font-size: 24px;
}

.download__btn-text small {
  display: block;
  font-size: var(--fs-xs);
  font-weight: 400;
  opacity: 0.7;
}

.download__note {
  font-size: var(--fs-sm);
  opacity: 0.8;
}

/* ===== FAQ ===== */
.faq__list {
  max-width: 760px;
  margin: 0 auto;
}

.faq-item {
  background: var(--color-surface);
  border-radius: var(--radius-md);
  margin-bottom: var(--space-sm);
  box-shadow: var(--shadow-sm);
  overflow: hidden;
  transition: box-shadow var(--transition-base);
}

.faq-item--active {
  box-shadow: var(--shadow-md);
}

.faq-item__question {
  width: 100%;
  text-align: left;
  padding: var(--space-md) var(--space-lg);
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-size: var(--fs-base);
  font-weight: 600;
  color: var(--color-text);
  gap: var(--space-md);
}

.faq-item__question i {
  font-size: 20px;
  color: var(--color-primary);
  transition: transform var(--transition-base);
  flex-shrink: 0;
}

.faq-item--active .faq-item__question i {
  transform: rotate(180deg);
}

.faq-item__answer {
  max-height: 0;
  overflow: hidden;
  transition: max-height var(--transition-slow);
}

.faq-item--active .faq-item__answer {
  max-height: 300px;
}

.faq-item__answer-inner {
  padding: 0 var(--space-lg) var(--space-md);
  color: var(--color-text-secondary);
  font-size: var(--fs-base);
  line-height: 1.7;
}

/* ===== Footer ===== */
.footer {
  background: var(--color-surface);
  border-top: 1px solid var(--color-border);
  padding: var(--space-2xl) 0 var(--space-xl);
}

.footer__grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--space-xl);
  margin-bottom: var(--space-xl);
}

.footer__brand h3 {
  font-size: var(--fs-xl);
  font-weight: 800;
  margin-bottom: var(--space-sm);
  display: flex;
  align-items: center;
  gap: var(--space-sm);
}

.footer__brand p {
  color: var(--color-text-secondary);
  font-size: var(--fs-sm);
  max-width: 280px;
}

.footer__col h4 {
  font-size: var(--fs-sm);
  font-weight: 700;
  color: var(--color-text);
  margin-bottom: var(--space-md);
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.footer__col ul {
  display: flex;
  flex-direction: column;
  gap: var(--space-sm);
}

.footer__col a {
  color: var(--color-text-secondary);
  font-size: var(--fs-sm);
  transition: color var(--transition-fast);
}

.footer__col a:hover {
  color: var(--color-primary);
}

.footer__social {
  display: flex;
  gap: var(--space-sm);
  margin-top: var(--space-md);
}

.footer__social a {
  width: 40px;
  height: 40px;
  border-radius: var(--radius-sm);
  background: var(--color-bg);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 20px;
  color: var(--color-text-secondary);
  transition: all var(--transition-base);
}

.footer__social a:hover {
  background: var(--color-primary);
  color: #fff;
  transform: translateY(-2px);
}

.footer__bottom {
  border-top: 1px solid var(--color-border);
  padding-top: var(--space-lg);
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  align-items: center;
  gap: var(--space-md);
  font-size: var(--fs-sm);
  color: var(--color-text-muted);
}

.footer__bottom a {
  color: var(--color-text-muted);
}

.footer__bottom a:hover {
  color: var(--color-primary);
}

.footer__icp {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-md);
  align-items: center;
}

/* ===== Page Header (subpages) ===== */
.page-header {
  background: linear-gradient(160deg, var(--color-primary-lighter), var(--color-bg));
  padding: calc(var(--nav-height) + var(--space-2xl)) 0 var(--space-xl);
  text-align: center;
}

.page-header h1 {
  font-size: var(--fs-2xl);
  font-weight: 800;
  margin-bottom: var(--space-sm);
}

.page-header p {
  color: var(--color-text-secondary);
  font-size: var(--fs-base);
}

/* ===== Legal Page ===== */
.legal {
  padding: var(--space-xl) 0 var(--space-2xl);
}

.legal__content {
  max-width: 800px;
  margin: 0 auto;
  background: var(--color-surface);
  border-radius: var(--radius-lg);
  padding: var(--space-xl) var(--space-lg);
  box-shadow: var(--shadow-sm);
}

.legal__content h2 {
  font-size: var(--fs-xl);
  font-weight: 700;
  margin-top: var(--space-xl);
  margin-bottom: var(--space-md);
}

.legal__content h2:first-child {
  margin-top: 0;
}

.legal__content h3 {
  font-size: var(--fs-lg);
  font-weight: 600;
  margin-top: var(--space-lg);
  margin-bottom: var(--space-sm);
}

.legal__content p {
  color: var(--color-text-secondary);
  margin-bottom: var(--space-md);
}

.legal__content ul {
  list-style: disc;
  padding-left: var(--space-lg);
  margin-bottom: var(--space-md);
}

.legal__content ul li {
  color: var(--color-text-secondary);
  margin-bottom: var(--space-sm);
}

.legal__updated {
  font-size: var(--fs-sm);
  color: var(--color-text-muted);
  margin-bottom: var(--space-lg);
  padding-bottom: var(--space-md);
  border-bottom: 1px solid var(--color-border);
}

/* ===== 404 Page ===== */
.error-page {
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  text-align: center;
  padding: var(--space-xl);
  padding-top: var(--nav-height);
}

.error-page__code {
  font-size: 120px;
  font-weight: 800;
  line-height: 1;
  background: linear-gradient(135deg, var(--color-primary), var(--color-gradient-end));
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
  margin-bottom: var(--space-md);
}

.error-page h1 {
  font-size: var(--fs-2xl);
  font-weight: 700;
  margin-bottom: var(--space-md);
}

.error-page p {
  color: var(--color-text-secondary);
  margin-bottom: var(--space-xl);
  font-size: var(--fs-lg);
}

.error-page__actions {
  display: flex;
  gap: var(--space-md);
  justify-content: center;
  flex-wrap: wrap;
}

/* ===== Scroll Animation ===== */
.fade-in {
  opacity: 0;
  transform: translateY(30px);
  transition: opacity var(--transition-slow), transform var(--transition-slow);
}

.fade-in.visible {
  opacity: 1;
  transform: translateY(0);
}

.fade-in-left {
  opacity: 0;
  transform: translateX(-30px);
  transition: opacity var(--transition-slow), transform var(--transition-slow);
}

.fade-in-left.visible {
  opacity: 1;
  transform: translateX(0);
}

.fade-in-right {
  opacity: 0;
  transform: translateX(30px);
  transition: opacity var(--transition-slow), transform var(--transition-slow);
}

.fade-in-right.visible {
  opacity: 1;
  transform: translateX(0);
}

/* ===== Responsive ===== */
@media (min-width: 640px) {
  .scenarios__grid {
    grid-template-columns: repeat(2, 1fr);
  }

  .footer__grid {
    grid-template-columns: 2fr 1fr 1fr;
  }
}

@media (min-width: 768px) {
  :root {
    --fs-3xl: 3rem;
    --fs-4xl: 4rem;
  }

  .nav__links {
    display: flex;
  }

  .nav__toggle {
    display: none;
  }

  .nav__mobile {
    display: none;
  }

  .hero__inner {
    grid-template-columns: 1fr 1fr;
    gap: var(--space-xl);
  }

  .features__grid {
    grid-template-columns: repeat(3, 1fr);
  }

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

  .adv__item {
    grid-template-columns: 1fr 1fr;
    gap: var(--space-2xl);
  }

  .adv__item--reverse .adv__visual {
    order: 2;
  }

  .footer__grid {
    grid-template-columns: 2fr 1fr 1fr 1fr;
  }
}

@media (min-width: 1024px) {
  .scenarios__grid {
    grid-template-columns: repeat(4, 1fr);
  }

  .hero__title {
    font-size: var(--fs-4xl);
  }
}

@media (max-width: 767px) {
  .hero__img {
    max-height: 420px;
  }

  .phone-badge {
    padding: var(--space-xs) var(--space-sm);
  }

  .phone-badge__icon {
    width: 28px;
    height: 28px;
    font-size: 14px;
  }

  .phone-badge__text strong {
    font-size: var(--fs-xs);
  }

  .phone-badge__text span {
    font-size: 10px;
  }

  .phone-badge--1 {
    left: -8px;
  }

  .phone-badge--2 {
    right: -8px;
  }

  .phone-badge--3 {
    left: 0;
  }

  .screenshot-card {
    width: 240px;
  }
}

/* ===== Reduced Motion ===== */
@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;
  }

  .fade-in,
  .fade-in-left,
  .fade-in-right {
    opacity: 1;
    transform: none;
  }
}

/* ===== No-JS Fallback ===== */
.no-js .faq-item__answer {
  max-height: none;
}

.no-js .fade-in,
.no-js .fade-in-left,
.no-js .fade-in-right {
  opacity: 1;
  transform: none;
}

/* ===== 举报反馈悬浮按钮 ===== */
.report-fab {
  position: fixed;
  right: 24px;
  bottom: 24px;
  display: flex;
  align-items: center;
  gap: 6px;
  padding: 12px 20px;
  background: var(--color-surface);
  color: var(--color-text);
  border-radius: var(--radius-full);
  box-shadow: var(--shadow-md);
  font-size: var(--fs-sm);
  font-weight: 600;
  z-index: 999;
  transition: all var(--transition-base);
}

.report-fab:hover {
  background: var(--color-primary);
  color: #fff;
  transform: translateY(-2px);
  box-shadow: var(--shadow-lg);
}

.report-fab i {
  font-size: 18px;
}

@media (max-width: 767px) {
  .report-fab {
    right: 16px;
    bottom: 16px;
    padding: 10px 16px;
  }
}