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

:root {
  --bg: #0d0d0f;
  --bg2: #141417;
  --bg3: #1c1c21;
  --border: #2a2a32;
  --text: #e8e8f0;
  --text2: #9090a8;
  --accent: #a78bfa;
  --accent2: #7c3aed;
  --accent-glow: rgba(167, 139, 250, 0.15);
  --green: #34d399;
  --red: #f87171;
  --yellow: #fbbf24;
  --radius: 12px;
  --radius-sm: 8px;
  --shadow: 0 4px 24px rgba(0,0,0,0.4);
}

html { scroll-behavior: smooth; }

body {
  background: var(--bg);
  color: var(--text);
  font-family: 'Pretendard', 'Apple SD Gothic Neo', 'Noto Sans KR', sans-serif;
  line-height: 1.6;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

a { color: var(--accent); text-decoration: none; }
a:hover { text-decoration: underline; }

main { flex: 1; max-width: 860px; margin: 0 auto; padding: 2rem 1.25rem 4rem; width: 100%; }

footer {
  text-align: center;
  padding: 1.5rem;
  color: var(--text2);
  font-size: 0.85rem;
  border-top: 1px solid var(--border);
}

/* ===== NAVBAR ===== */
.navbar {
  background: rgba(13,13,15,0.92);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
  position: sticky;
  top: 0;
  z-index: 100;
}
.nav-inner {
  max-width: 1080px;
  margin: 0 auto;
  padding: 0 1.25rem;
  height: 56px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}
.nav-logo {
  font-size: 1.15rem;
  font-weight: 700;
  color: var(--text);
  letter-spacing: -0.02em;
}
.nav-logo:hover { text-decoration: none; color: var(--accent); }
.nav-right {
  display: flex;
  align-items: center;
  gap: 0.75rem;
}
.nav-right a, .nav-right button {
  font-size: 0.875rem;
  padding: 0.4rem 0.9rem;
  border-radius: var(--radius-sm);
  cursor: pointer;
  transition: all 0.2s;
}
.btn-nav-ghost {
  background: transparent;
  border: 1px solid var(--border);
  color: var(--text2);
}
.btn-nav-ghost:hover { border-color: var(--accent); color: var(--accent); background: transparent; }
.btn-nav-primary {
  background: var(--accent2);
  border: none;
  color: #fff;
}
.btn-nav-primary:hover { background: var(--accent); }
.nav-user-info {
  display: flex;
  align-items: center;
  gap: 0.5rem;
}
.plan-chip {
  font-size: 0.72rem;
  font-weight: 700;
  padding: 0.2rem 0.55rem;
  border-radius: 99px;
  text-transform: uppercase;
  letter-spacing: 0.04em;
}
.plan-chip.free { background: var(--bg3); color: var(--text2); border: 1px solid var(--border); }
.plan-chip.starter { background: rgba(251,191,36,0.15); color: var(--yellow); border: 1px solid rgba(251,191,36,0.3); }
.plan-chip.pro { background: rgba(167,139,250,0.15); color: var(--accent); border: 1px solid rgba(167,139,250,0.3); }

/* ===== MODAL ===== */
.modal-overlay {
  position: fixed; inset: 0;
  background: rgba(0,0,0,0.7);
  backdrop-filter: blur(4px);
  z-index: 200;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 1rem;
}
.modal-overlay.hidden { display: none; }
.modal-box {
  background: var(--bg2);
  border: 1px solid var(--border);
  border-radius: 16px;
  padding: 2rem;
  width: 100%;
  max-width: 420px;
  position: relative;
  box-shadow: var(--shadow);
  animation: fadeUp 0.2s ease;
}
@keyframes fadeUp {
  from { opacity: 0; transform: translateY(16px); }
  to { opacity: 1; transform: translateY(0); }
}
.modal-close {
  position: absolute; top: 1rem; right: 1rem;
  background: none; border: none;
  color: var(--text2); font-size: 1.1rem; cursor: pointer;
  width: 28px; height: 28px;
  display: flex; align-items: center; justify-content: center;
  border-radius: 50%;
  transition: background 0.2s;
}
.modal-close:hover { background: var(--bg3); color: var(--text); }

/* AUTH FORMS */
.auth-title { font-size: 1.3rem; font-weight: 700; margin-bottom: 0.25rem; }
.auth-sub { color: var(--text2); font-size: 0.9rem; margin-bottom: 1.5rem; }
.auth-form { display: flex; flex-direction: column; gap: 0.75rem; }
.auth-input {
  background: var(--bg3);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  color: var(--text);
  font-size: 0.95rem;
  padding: 0.7rem 1rem;
  outline: none;
  transition: border-color 0.2s;
  width: 100%;
}
.auth-input:focus { border-color: var(--accent); }
.auth-input::placeholder { color: var(--text2); }

.btn-auth-primary {
  background: var(--accent2);
  color: #fff;
  border: none;
  border-radius: var(--radius-sm);
  padding: 0.75rem;
  font-size: 0.95rem;
  font-weight: 600;
  cursor: pointer;
  transition: background 0.2s;
}
.btn-auth-primary:hover { background: var(--accent); }
.btn-auth-primary:disabled { opacity: 0.6; cursor: not-allowed; }

.btn-google {
  background: var(--bg3);
  border: 1px solid var(--border);
  color: var(--text);
  border-radius: var(--radius-sm);
  padding: 0.7rem;
  font-size: 0.9rem;
  cursor: pointer;
  display: flex; align-items: center; justify-content: center; gap: 0.5rem;
  transition: border-color 0.2s, background 0.2s;
}
.btn-google:hover { border-color: var(--accent); background: var(--accent-glow); }

.auth-divider {
  text-align: center;
  color: var(--text2);
  font-size: 0.85rem;
  position: relative;
  margin: 0.25rem 0;
}
.auth-divider::before, .auth-divider::after {
  content: '';
  position: absolute;
  top: 50%; width: 40%; height: 1px;
  background: var(--border);
}
.auth-divider::before { left: 0; }
.auth-divider::after { right: 0; }

.auth-switch {
  text-align: center;
  font-size: 0.875rem;
  color: var(--text2);
  margin-top: 0.5rem;
}
.auth-switch button {
  background: none; border: none;
  color: var(--accent); cursor: pointer; font-size: inherit;
  padding: 0;
}
.auth-error {
  background: rgba(248,113,113,0.1);
  border: 1px solid rgba(248,113,113,0.3);
  border-radius: var(--radius-sm);
  padding: 0.6rem 0.9rem;
  font-size: 0.875rem;
  color: var(--red);
}
.auth-success {
  background: rgba(52,211,153,0.1);
  border: 1px solid rgba(52,211,153,0.3);
  border-radius: var(--radius-sm);
  padding: 0.6rem 0.9rem;
  font-size: 0.875rem;
  color: var(--green);
}

/* ===== HERO ===== */
.hero {
  text-align: center;
  padding: 3.5rem 0 2.5rem;
}
.hero-badge {
  display: inline-block;
  background: var(--accent-glow);
  border: 1px solid rgba(167,139,250,0.3);
  border-radius: 99px;
  padding: 0.3rem 1rem;
  font-size: 0.8rem;
  color: var(--accent);
  letter-spacing: 0.04em;
  margin-bottom: 1rem;
}
.hero h1 {
  font-size: clamp(2rem, 5vw, 2.8rem);
  font-weight: 800;
  line-height: 1.25;
  letter-spacing: -0.03em;
  margin-bottom: 1rem;
}
.accent { color: var(--accent); }
.hero-sub { color: var(--text2); font-size: 1rem; line-height: 1.7; }

/* ===== USAGE BANNER ===== */
.usage-banner {
  background: var(--bg3);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 0.75rem 1.25rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-size: 0.9rem;
  margin-bottom: 1.5rem;
  flex-wrap: wrap;
  gap: 0.5rem;
}
.usage-banner.hidden { display: none; }
.usage-upgrade {
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--accent);
  white-space: nowrap;
}

/* ===== HOW TO ===== */
.how-to { margin-bottom: 2.5rem; }
.how-to h2 { font-size: 1.1rem; font-weight: 700; margin-bottom: 1rem; }
.steps { display: flex; flex-direction: column; gap: 0.75rem; }
.step {
  display: flex; align-items: flex-start; gap: 1rem;
  background: var(--bg2); border: 1px solid var(--border);
  border-radius: var(--radius); padding: 1rem 1.25rem;
}
.step-num {
  min-width: 28px; height: 28px;
  background: var(--accent2);
  color: #fff; border-radius: 50%;
  display: flex; align-items: center; justify-content: center;
  font-size: 0.85rem; font-weight: 700;
}
.step strong { display: block; margin-bottom: 0.2rem; }
.step a { font-size: 0.9rem; }

/* ===== API SECTION ===== */
.api-section { display: flex; flex-direction: column; gap: 1.25rem; margin-bottom: 2rem; }
.api-group {
  background: var(--bg2); border: 1px solid var(--border);
  border-radius: var(--radius); padding: 1.25rem;
}
.api-group label {
  display: block; font-weight: 600; margin-bottom: 0.6rem; font-size: 0.95rem;
}
.label-sub { color: var(--text2); font-weight: 400; font-size: 0.85rem; }
.input-row { display: flex; gap: 0.5rem; }
.input-row input {
  flex: 1;
  background: var(--bg3); border: 1px solid var(--border);
  border-radius: var(--radius-sm); color: var(--text);
  font-size: 0.9rem; padding: 0.6rem 0.9rem; outline: none;
  transition: border-color 0.2s;
}
.input-row input:focus { border-color: var(--accent); }
.btn-toggle {
  background: var(--bg3); border: 1px solid var(--border);
  color: var(--text2); border-radius: var(--radius-sm);
  padding: 0 0.9rem; cursor: pointer; font-size: 0.85rem;
  transition: all 0.2s; white-space: nowrap;
}
.btn-toggle:hover { border-color: var(--accent); color: var(--accent); }
.api-hint { color: var(--text2); font-size: 0.82rem; margin-top: 0.5rem; }
.api-note { color: var(--text2); font-size: 0.8rem; margin-top: 0.75rem; line-height: 1.6; }

/* ===== GENERATE SECTION ===== */
.generate-section { margin-bottom: 2rem; }
.topic-group { margin-bottom: 1rem; }
.topic-group label { display: block; font-weight: 600; margin-bottom: 0.6rem; }
.topic-group textarea {
  width: 100%;
  background: var(--bg2); border: 1px solid var(--border);
  border-radius: var(--radius); color: var(--text);
  font-size: 0.95rem; padding: 0.9rem 1.1rem;
  resize: vertical; outline: none; line-height: 1.6;
  font-family: inherit; transition: border-color 0.2s;
}
.topic-group textarea:focus { border-color: var(--accent); }
.topic-group textarea::placeholder { color: var(--text2); }

.btn-generate {
  width: 100%;
  background: var(--accent2);
  color: #fff; border: none;
  border-radius: var(--radius); padding: 1rem;
  font-size: 1.05rem; font-weight: 700;
  cursor: pointer; transition: all 0.2s;
  letter-spacing: -0.01em;
}
.btn-generate:hover { background: var(--accent); transform: translateY(-1px); box-shadow: 0 8px 24px rgba(124,58,237,0.35); }
.btn-generate:disabled { opacity: 0.5; cursor: not-allowed; transform: none; box-shadow: none; }

/* ===== RESULTS ===== */
.results-section { margin-top: 2rem; }
.tabs { display: flex; gap: 0.5rem; flex-wrap: wrap; margin-bottom: 1rem; }
.tab {
  background: var(--bg3); border: 1px solid var(--border);
  color: var(--text2); border-radius: var(--radius-sm);
  padding: 0.5rem 1rem; cursor: pointer; font-size: 0.875rem;
  transition: all 0.2s;
}
.tab:hover { border-color: var(--accent); color: var(--accent); }
.tab.active {
  background: var(--accent2); border-color: var(--accent2);
  color: #fff; font-weight: 600;
}
.results-content {
  background: var(--bg2); border: 1px solid var(--border);
  border-radius: var(--radius); padding: 1.5rem;
  min-height: 200px; white-space: pre-wrap; line-height: 1.8;
  font-size: 0.95rem;
}

/* ===== BUTTONS (shared) ===== */
.btn-primary {
  display: inline-block;
  background: var(--accent2); color: #fff;
  border: none; border-radius: var(--radius-sm);
  padding: 0.7rem 1.4rem; font-size: 0.9rem; font-weight: 600;
  cursor: pointer; transition: all 0.2s; text-align: center;
}
.btn-primary:hover { background: var(--accent); text-decoration: none; color: #fff; }
.btn-secondary {
  display: inline-block;
  background: var(--bg3); color: var(--text);
  border: 1px solid var(--border); border-radius: var(--radius-sm);
  padding: 0.7rem 1.4rem; font-size: 0.9rem; font-weight: 600;
  cursor: pointer; transition: all 0.2s;
}
.btn-secondary:hover { border-color: var(--accent); color: var(--accent); }
.btn-outline {
  display: inline-block;
  background: transparent; color: var(--accent);
  border: 1px solid var(--accent); border-radius: var(--radius-sm);
  padding: 0.7rem 1.4rem; font-size: 0.9rem; font-weight: 600;
  cursor: pointer; transition: all 0.2s; text-align: center;
}
.btn-outline:hover { background: var(--accent-glow); text-decoration: none; }

/* ===== LOADING SPINNER ===== */
.spinner {
  display: inline-block; width: 18px; height: 18px;
  border: 2px solid rgba(255,255,255,0.3);
  border-top-color: #fff; border-radius: 50%;
  animation: spin 0.7s linear infinite;
  vertical-align: middle; margin-right: 0.4rem;
}
@keyframes spin { to { transform: rotate(360deg); } }

/* ===== TOAST ===== */
.toast-container {
  position: fixed; bottom: 1.5rem; right: 1.5rem;
  display: flex; flex-direction: column; gap: 0.5rem;
  z-index: 999;
}
.toast {
  background: var(--bg2); border: 1px solid var(--border);
  border-radius: var(--radius-sm); padding: 0.75rem 1.1rem;
  font-size: 0.875rem; box-shadow: var(--shadow);
  animation: slideIn 0.25s ease; max-width: 320px;
}
.toast.success { border-color: var(--green); color: var(--green); }
.toast.error { border-color: var(--red); color: var(--red); }
.toast.info { border-color: var(--accent); color: var(--accent); }
@keyframes slideIn { from { opacity: 0; transform: translateX(20px); } to { opacity: 1; transform: translateX(0); } }

/* ===== RESPONSIVE ===== */
@media (max-width: 600px) {
  .steps { gap: 0.5rem; }
  .tabs { gap: 0.35rem; }
  .tab { font-size: 0.8rem; padding: 0.4rem 0.7rem; }
  .hero h1 { font-size: 1.75rem; }
}
/* ===== FOOTER 개선 ===== */
footer {
  border-top: 1px solid var(--border);
  padding: 2rem 1.25rem;
}
.footer-inner {
  max-width: 860px;
  margin: 0 auto;
}
.footer-top {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 1rem;
  flex-wrap: wrap;
  gap: 0.5rem;
}
.footer-brand {
  font-weight: 700;
  font-size: 1rem;
  color: var(--text);
}
.footer-links {
  display: flex;
  gap: 1.25rem;
}
.footer-links a {
  font-size: 0.875rem;
  color: var(--text2);
}
.footer-links a:hover { color: var(--accent); }
.footer-bottom {
  border-top: 1px solid var(--border);
  padding-top: 1rem;
  display: flex;
  flex-direction: column;
  gap: 0.25rem;
}
.footer-bottom p {
  font-size: 0.8rem;
  color: var(--text2);
}