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

:root {
  --bg:        #0d0d0f;
  --bg-2:      #111114;
  --bg-3:      #17171b;
  --bg-4:      #1e1e24;
  --border:    #2a2a32;
  --border-2:  #353540;

  --text:      #e8e8f0;
  --text-2:    #a0a0b8;
  --text-3:    #5a5a72;

  --accent:    #6c63ff;
  --accent-2:  #8b85ff;
  --accent-dim:#6c63ff22;

  --success:   #3ecf8e;
  --warn:      #f5a623;

  --radius:    12px;
  --radius-lg: 20px;
  --shadow:    0 4px 24px rgba(0,0,0,.45);
  --shadow-lg: 0 12px 48px rgba(0,0,0,.6);

  --font: 'Segoe UI', 'Apple SD Gothic Neo', sans-serif;
}

/* ===== LIGHT MODE ===== */
html.light {
  --bg:        #f5f5f7;
  --bg-2:      #ebebee;
  --bg-3:      #ffffff;
  --bg-4:      #f0f0f4;
  --border:    #d8d8e0;
  --border-2:  #c4c4d0;

  --text:      #111118;
  --text-2:    #4a4a60;
  --text-3:    #9090a8;

  --accent:    #5a52e8;
  --accent-2:  #4038d0;
  --accent-dim:#5a52e811;

  --shadow:    0 4px 24px rgba(0,0,0,.10);
  --shadow-lg: 0 12px 48px rgba(0,0,0,.14);
}

/* ===== THEME TOGGLE BUTTON ===== */
.theme-toggle {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 38px;
  height: 38px;
  border-radius: 50%;
  border: 1.5px solid var(--border-2);
  background: var(--bg-3);
  cursor: pointer;
  font-size: 1rem;
  transition: border-color .2s, background .2s, transform .2s;
  flex-shrink: 0;
}
.theme-toggle:hover {
  border-color: var(--accent);
  transform: rotate(20deg);
}

/* Show correct icon per mode */
.theme-toggle__icon { line-height: 1; }
.theme-toggle__icon--light { display: none; }

html.light .theme-toggle__icon--dark  { display: none; }
html.light .theme-toggle__icon--light { display: inline; }

/* Light mode: fix hero orb visibility */
html.light .hero__orb { opacity: .08; }
html.light .hero__grid { opacity: .15; }

/* Light mode: nav backdrop */
html.light .nav {
  background: rgba(245,245,247,.88);
  border-bottom-color: var(--border);
}

/* Light mode: tag colors */
html.light .tag--toeic { background: #ddeeff; color: #2255aa; border-color: #bbddff; }
html.light .tag--toefl { background: #ddfff0; color: #1a7a4a; border-color: #aaeedd; }
html.light .tag--csat  { background: #ffeeee; color: #aa2222; border-color: #ffcccc; }
html.light .tag--noun  { background: var(--bg-4); color: var(--text-2); border-color: var(--border); }

/* Light mode: section--dark uses a lighter shade */
html.light .section--dark { background: #ebebee; }

/* Light mode: CTA section */
html.light .cta-section { background: linear-gradient(135deg, #eeeeff 0%, #f5f5f7 60%, #eef0ff 100%); }

html { scroll-behavior: smooth; }

body {
  font-family: var(--font);
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
  overflow-x: hidden;
}

a { color: inherit; text-decoration: none; }
ul { list-style: none; }

.container {
  max-width: 1140px;
  margin: 0 auto;
  padding: 0 24px;
}

/* ===== BUTTONS ===== */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 10px 22px;
  border-radius: var(--radius);
  font-weight: 600;
  font-size: 0.9rem;
  cursor: pointer;
  transition: all .2s;
  border: 1.5px solid transparent;
  white-space: nowrap;
}

.btn--primary {
  background: var(--accent);
  color: #fff;
  border-color: var(--accent);
}
.btn--primary:hover { background: var(--accent-2); border-color: var(--accent-2); transform: translateY(-1px); box-shadow: 0 4px 20px rgba(108,99,255,.4); }

.btn--ghost {
  background: transparent;
  color: var(--text-2);
  border-color: var(--border-2);
}
.btn--ghost:hover { border-color: var(--accent); color: var(--accent); }

.btn--lg { padding: 14px 32px; font-size: 1rem; border-radius: 14px; }
.btn--sm { padding: 6px 14px; font-size: 0.8rem; border-radius: 8px; }

/* ===== NAV ===== */
.nav {
  position: fixed;
  top: 0; left: 0; right: 0;
  z-index: 100;
  background: rgba(13,13,15,.85);
  backdrop-filter: blur(14px);
  border-bottom: 1px solid var(--border);
}

.nav__inner {
  display: flex;
  align-items: center;
  gap: 40px;
  max-width: 1140px;
  margin: 0 auto;
  padding: 0 24px;
  height: 64px;
}

.nav__logo {
  font-size: 1.1rem;
  font-weight: 800;
  letter-spacing: -.5px;
  flex-shrink: 0;
}
.nav__logo span { color: var(--accent); }

.nav__links {
  display: flex;
  gap: 32px;
  flex: 1;
}
.nav__links a {
  font-size: 0.9rem;
  color: var(--text-2);
  transition: color .2s;
}
.nav__links a:hover { color: var(--text); }

.nav__actions { display: flex; gap: 10px; margin-left: auto; }

.nav__hamburger {
  display: none;
  flex-direction: column;
  gap: 5px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 4px;
  margin-left: auto;
}
.nav__hamburger span {
  display: block;
  width: 22px; height: 2px;
  background: var(--text-2);
  border-radius: 2px;
  transition: all .3s;
}

.nav__mobile {
  display: none;
  flex-direction: column;
  gap: 12px;
  padding: 16px 24px 20px;
  border-top: 1px solid var(--border);
  background: var(--bg-2);
}
.nav__mobile a { color: var(--text-2); font-size: 0.95rem; }
.nav__mobile.open { display: flex; }

@media (max-width: 768px) {
  .nav__links, .nav__actions { display: none; }
  .nav__hamburger { display: flex; }
}

/* ===== SECTIONS ===== */
.section {
  padding: 96px 0;
}
.section--dark { background: var(--bg-2); }

.section__header {
  text-align: center;
  margin-bottom: 56px;
}
.section__sub {
  font-size: 0.8rem;
  font-weight: 700;
  letter-spacing: 2px;
  text-transform: uppercase;
  color: var(--accent);
  margin-bottom: 12px;
}
.section__title {
  font-size: clamp(1.8rem, 4vw, 2.5rem);
  font-weight: 800;
  letter-spacing: -.5px;
  color: var(--text);
}
.section__desc {
  margin-top: 14px;
  color: var(--text-2);
  font-size: 1rem;
}

/* ===== HERO ===== */
.hero {
  position: relative;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  padding-top: 80px;
  overflow: hidden;
}

.hero__bg {
  position: absolute;
  inset: 0;
  pointer-events: none;
  z-index: 0;
}

.hero__orb {
  position: absolute;
  border-radius: 50%;
  filter: blur(80px);
  opacity: .18;
}
.hero__orb--1 {
  width: 600px; height: 600px;
  background: var(--accent);
  top: -200px; left: -150px;
}
.hero__orb--2 {
  width: 400px; height: 400px;
  background: #a78bfa;
  bottom: -100px; right: -100px;
}

.hero__grid {
  position: absolute;
  inset: 0;
  background-image:
    linear-gradient(var(--border) 1px, transparent 1px),
    linear-gradient(90deg, var(--border) 1px, transparent 1px);
  background-size: 48px 48px;
  opacity: .25;
  mask-image: radial-gradient(ellipse 80% 80% at 50% 50%, black, transparent);
}

.hero__content {
  position: relative;
  z-index: 1;
  text-align: center;
  padding-top: 48px;
  padding-bottom: 32px;
}

.hero__badge {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  background: var(--accent-dim);
  border: 1px solid var(--accent);
  color: var(--accent-2);
  font-size: 0.8rem;
  font-weight: 600;
  padding: 6px 14px;
  border-radius: 100px;
  margin-bottom: 28px;
  letter-spacing: .5px;
}
.badge__dot {
  width: 7px; height: 7px;
  border-radius: 50%;
  background: var(--accent);
  animation: pulse 2s infinite;
}
@keyframes pulse {
  0%,100% { opacity: 1; }
  50% { opacity: .4; }
}

.hero__title {
  font-size: clamp(2.2rem, 6vw, 3.8rem);
  font-weight: 900;
  line-height: 1.2;
  letter-spacing: -.5px;
  margin-bottom: 22px;
}

.gradient-text {
  background: linear-gradient(135deg, var(--accent), #a78bfa, #818cf8);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.hero__desc {
  font-size: 1.05rem;
  color: var(--text-2);
  line-height: 1.75;
  margin-bottom: 36px;
}

.hero__cta {
  display: flex;
  gap: 14px;
  justify-content: center;
  flex-wrap: wrap;
  margin-bottom: 52px;
}

.hero__stats {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 32px;
  flex-wrap: wrap;
}
.stat { text-align: center; }
.stat strong {
  display: block;
  font-size: 1.6rem;
  font-weight: 800;
  color: var(--text);
}
.stat span { font-size: 0.8rem; color: var(--text-3); }
.stat__divider {
  width: 1px; height: 36px;
  background: var(--border);
}

/* ===== WORD CARD (Hero preview) ===== */
.hero__card-wrap {
  position: relative;
  z-index: 1;
  display: flex;
  justify-content: center;
  padding-bottom: 60px;
}

.word-card {
  background: var(--bg-3);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 24px 28px;
  width: 100%;
  max-width: 480px;
  box-shadow: var(--shadow-lg);
  animation: floatCard 4s ease-in-out infinite;
}
@keyframes floatCard {
  0%,100% { transform: translateY(0); }
  50% { transform: translateY(-8px); }
}

.word-card__header { display: flex; gap: 8px; margin-bottom: 16px; }

.tag {
  display: inline-block;
  padding: 3px 10px;
  border-radius: 100px;
  font-size: 0.72rem;
  font-weight: 700;
  letter-spacing: .5px;
}
.tag--toeic  { background: #1a2740; color: #6cabff; border: 1px solid #2a4060; }
.tag--toefl  { background: #1a2a1a; color: #4ecb71; border: 1px solid #2a4a2a; }
.tag--csat   { background: #2a1a1a; color: #ff8080; border: 1px solid #4a2a2a; }
.tag--noun   { background: var(--bg-4); color: var(--text-2); border: 1px solid var(--border); }

.word-card__word {
  font-size: 2rem;
  font-weight: 800;
  color: var(--text);
  margin-bottom: 4px;
}
.word-card__ipa {
  font-size: 0.9rem;
  color: var(--text-3);
  margin-bottom: 14px;
}
.word-card__meaning {
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--accent-2);
  margin-bottom: 12px;
}
.word-card__example {
  font-size: 0.9rem;
  color: var(--text-2);
  font-style: italic;
  padding: 10px 14px;
  background: var(--bg-4);
  border-radius: 8px;
  border-left: 3px solid var(--accent);
  margin-bottom: 12px;
}
.word-card__example em { color: var(--accent-2); font-style: normal; font-weight: 600; }
.word-card__tip {
  font-size: 0.82rem;
  color: var(--text-3);
  margin-bottom: 16px;
}

.word-card__generating {
  display: flex;
  align-items: center;
  gap: 6px;
  opacity: 0;
  transition: opacity .4s;
}
.word-card__generating.active { opacity: 1; }
.gen__dot {
  width: 6px; height: 6px;
  border-radius: 50%;
  background: var(--accent);
  animation: genBounce 1.2s infinite;
}
.gen__dot:nth-child(2) { animation-delay: .15s; }
.gen__dot:nth-child(3) { animation-delay: .3s; }
@keyframes genBounce {
  0%,80%,100% { transform: scale(.6); opacity: .4; }
  40% { transform: scale(1); opacity: 1; }
}
.gen__label { font-size: 0.78rem; color: var(--text-3); }

/* ===== FEATURES ===== */
.features__grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 20px;
}
@media (max-width: 900px) { .features__grid { grid-template-columns: repeat(2,1fr); } }
@media (max-width: 600px) { .features__grid { grid-template-columns: 1fr; } }

.feature-card {
  background: var(--bg-3);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 28px;
  transition: border-color .25s, transform .25s;
}
.feature-card:hover {
  border-color: var(--accent);
  transform: translateY(-4px);
  box-shadow: var(--shadow);
}
.feature-card--accent {
  background: linear-gradient(145deg, #17171b, #1c1a2e);
  border-color: var(--accent);
}

.feature-card__icon { font-size: 2rem; margin-bottom: 16px; }
.feature-card h3 { font-size: 1rem; font-weight: 700; margin-bottom: 10px; }
.feature-card p { font-size: 0.88rem; color: var(--text-2); line-height: 1.65; }

/* ===== STEPS ===== */
.steps {
  display: flex;
  align-items: flex-start;
  justify-content: center;
  gap: 16px;
  flex-wrap: wrap;
}

.step {
  background: var(--bg-3);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 28px 24px;
  flex: 1;
  min-width: 220px;
  max-width: 300px;
  text-align: center;
  transition: border-color .25s;
}
.step:hover { border-color: var(--accent); }

.step__num {
  font-size: 2.5rem;
  font-weight: 900;
  color: var(--accent-dim);
  -webkit-text-stroke: 2px var(--accent);
  margin-bottom: 14px;
  line-height: 1;
}
.step__content h3 { font-size: 1rem; font-weight: 700; margin-bottom: 10px; }
.step__content p { font-size: 0.87rem; color: var(--text-2); line-height: 1.65; }

.step__arrow {
  font-size: 1.5rem;
  color: var(--text-3);
  padding-top: 40px;
  flex-shrink: 0;
}
@media (max-width: 700px) { .step__arrow { display: none; } }

/* ===== TAGS ===== */
.tags__grid {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  justify-content: center;
}
.tag-item {
  padding: 10px 22px;
  border: 1.5px solid var(--border-2);
  border-radius: 100px;
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--text-2);
  cursor: pointer;
  transition: all .2s;
}
.tag-item:hover, .tag-item--active {
  border-color: var(--accent);
  color: var(--accent-2);
  background: var(--accent-dim);
}
.tag-item--custom {
  border-style: dashed;
  color: var(--text-3);
}
.tag-item--custom:hover {
  border-color: var(--success);
  color: var(--success);
  background: rgba(62,207,142,.1);
}

/* ===== AI CARDS ===== */
.ai__grid {
  display: flex;
  gap: 20px;
  justify-content: center;
  flex-wrap: wrap;
}

.ai-card {
  background: var(--bg-3);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 28px 32px;
  text-align: center;
  min-width: 220px;
  flex: 1;
  max-width: 280px;
  position: relative;
  transition: border-color .25s, transform .25s;
}
.ai-card:hover { border-color: var(--border-2); transform: translateY(-3px); }
.ai-card--featured {
  border-color: var(--accent);
  background: linear-gradient(145deg, #17171b, #1c1a2e);
}
.ai-card--featured:hover { border-color: var(--accent-2); }

.ai-card__badge {
  position: absolute;
  top: -12px; left: 50%; transform: translateX(-50%);
  background: var(--accent);
  color: #fff;
  font-size: 0.72rem;
  font-weight: 700;
  padding: 3px 12px;
  border-radius: 100px;
}
.ai-card__name { font-size: 1.1rem; font-weight: 800; margin-bottom: 6px; }
.ai-card__models { font-size: 0.82rem; color: var(--accent-2); margin-bottom: 10px; font-weight: 600; }
.ai-card__desc { font-size: 0.83rem; color: var(--text-2); }

/* ===== COMMUNITY ===== */
.community__grid {
  display: grid;
  grid-template-columns: repeat(3,1fr);
  gap: 20px;
}
@media (max-width: 900px) { .community__grid { grid-template-columns: 1fr 1fr; } }
@media (max-width: 600px) { .community__grid { grid-template-columns: 1fr; } }

.community-card {
  background: var(--bg-3);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 22px;
  display: flex;
  flex-direction: column;
  gap: 10px;
  transition: border-color .25s, transform .25s;
}
.community-card:hover { border-color: var(--border-2); transform: translateY(-3px); }

.community-card__top {
  display: flex;
  justify-content: space-between;
  align-items: center;
}
.community-card__likes { font-size: 0.82rem; color: #ff6b8a; }

.community-card h4 { font-size: 0.97rem; font-weight: 700; color: var(--text); }
.community-card p { font-size: 0.83rem; color: var(--text-2); line-height: 1.5; flex: 1; }

.community-card__footer {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-top: 4px;
}
.community-card__footer span { font-size: 0.78rem; color: var(--text-3); }

/* ===== CTA ===== */
.cta-section {
  background: linear-gradient(135deg, #12101f 0%, #0d0d0f 60%, #0f1220 100%);
  border-top: 1px solid var(--border);
  border-bottom: 1px solid var(--border);
}
.cta-section__inner {
  text-align: center;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 16px;
}
.cta-section h2 { font-size: clamp(1.8rem,4vw,2.6rem); font-weight: 800; }
.cta-section p { color: var(--text-2); font-size: 1rem; margin-bottom: 8px; }

/* ===== FOOTER ===== */
.footer {
  background: var(--bg-2);
  border-top: 1px solid var(--border);
  padding: 56px 0 0;
}
.footer__inner {
  display: flex;
  justify-content: space-between;
  gap: 40px;
  flex-wrap: wrap;
  padding-bottom: 40px;
}
.footer__brand p { font-size: 0.85rem; color: var(--text-3); margin-top: 10px; }

.footer__links { display: flex; gap: 48px; }
.footer__col {
  display: flex;
  flex-direction: column;
  gap: 10px;
}
.footer__col h5 { font-size: 0.8rem; font-weight: 700; letter-spacing: 1px; text-transform: uppercase; color: var(--text-2); margin-bottom: 4px; }
.footer__col a { font-size: 0.85rem; color: var(--text-3); transition: color .2s; }
.footer__col a:hover { color: var(--text); }

.footer__bottom {
  border-top: 1px solid var(--border);
  padding: 20px 24px;
  text-align: center;
  font-size: 0.8rem;
  color: var(--text-3);
}

/* ===== SCROLL REVEAL ===== */
.reveal {
  opacity: 0;
  transform: translateY(24px);
  transition: opacity .55s ease, transform .55s ease;
}
.reveal.visible {
  opacity: 1;
  transform: translateY(0);
}