/* ==========================================
   PRODUCT PAGE STYLES
   ========================================== */

/* ---- SUBNAV ---- */
.product-subnav {
  background: var(--color-white);
  border-bottom: 1px solid var(--color-border);
  position: sticky;
  top: 72px;
  z-index: 100;
}

.product-subnav-list {
  display: flex;
  gap: 0;
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
  scrollbar-width: none;
}

.product-subnav-list::-webkit-scrollbar { display: none; }

.product-subnav-list a {
  display: block;
  padding: 1rem 1.5rem;
  font-size: 0.82rem;
  letter-spacing: 0.12em;
  color: var(--color-text-sub);
  white-space: nowrap;
  border-bottom: 2px solid transparent;
  transition: color var(--transition), border-color var(--transition);
}

.product-subnav-list a:hover,
.product-subnav-list a.active {
  color: var(--color-primary);
  border-bottom-color: var(--color-primary);
}

/* ---- METHOD ---- */
.product-method {
  background: var(--color-bg);
  padding: var(--space-xl) 0;
}

.method-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1.5rem;
}

.method-card {
  background: var(--color-white);
  border-radius: var(--radius-md);
  padding: 2rem;
  box-shadow: var(--shadow-soft);
  transition: transform var(--transition), box-shadow var(--transition);
}

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

.method-card-area {
  display: flex;
  align-items: center;
  justify-content: center;
  height: 110px;
  margin-bottom: 1rem;
}

.method-num {
  font-family: var(--font-en);
  font-style: italic;
  font-size: 0.78rem;
  letter-spacing: 0.2em;
  color: var(--color-primary);
  margin-bottom: 0.5rem;
}

.method-card h3 {
  font-size: 1rem;
  margin-bottom: 0.8rem;
}

.method-card p {
  font-size: 0.84rem;
  color: var(--color-text-sub);
  line-height: 1.9;
  margin-bottom: 1rem;
}

.method-tip {
  background: var(--color-cream);
  border-radius: var(--radius-sm);
  padding: 0.7rem 1rem;
  font-size: 0.76rem;
  color: var(--color-text-sub);
  display: flex;
  align-items: flex-start;
  gap: 0.5rem;
  line-height: 1.6;
}

.method-tip i {
  color: var(--color-gold);
  margin-top: 0.1em;
  flex-shrink: 0;
}

/* ---- HOW TO USE ---- */
.product-howto {
  background: var(--color-cream);
  padding: var(--space-xl) 0;
}

.howto-steps {
  max-width: 700px;
  margin: 0 auto;
  display: flex;
  flex-direction: column;
  gap: 0;
  position: relative;
}

.howto-steps::before {
  content: '';
  position: absolute;
  top: 0; bottom: 0;
  left: 48px;
  width: 1px;
  background: var(--color-border);
}

.howto-step {
  display: flex;
  gap: 2rem;
  align-items: flex-start;
  padding: 1.5rem 0;
  position: relative;
}

.howto-step-num {
  font-family: var(--font-en);
  font-style: italic;
  font-size: 0.76rem;
  letter-spacing: 0.16em;
  color: var(--color-white);
  background: var(--color-primary);
  border-radius: var(--radius-sm);
  padding: 0.4rem 0.7rem;
  min-width: 64px;
  text-align: center;
  flex-shrink: 0;
  position: relative;
  z-index: 1;
}

.howto-step-body h3 {
  font-size: 1rem;
  margin-bottom: 0.5rem;
  color: var(--color-text);
}

.howto-step-body p {
  font-size: 0.88rem;
  color: var(--color-text-sub);
  line-height: 1.9;
}

.howto-caution {
  max-width: 700px;
  margin: 2rem auto 0;
  background: rgba(200,149,108,0.08);
  border: 1px solid rgba(200,149,108,0.2);
  border-radius: var(--radius-md);
  padding: 1.4rem 1.6rem;
  display: flex;
  gap: 1rem;
  align-items: flex-start;
}

.howto-caution i {
  color: var(--color-primary);
  font-size: 1.1rem;
  margin-top: 0.15em;
  flex-shrink: 0;
}

.howto-caution strong {
  display: block;
  font-size: 0.88rem;
  color: var(--color-text);
  margin-bottom: 0.3rem;
}

.howto-caution p {
  font-size: 0.82rem;
  color: var(--color-text-sub);
  line-height: 1.8;
}

/* ---- ROUTINE ---- */
.product-routine {
  background: var(--color-bg);
  padding: var(--space-xl) 0;
}

.routine-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1.5rem;
  max-width: 860px;
  margin: 0 auto;
}

.routine-card {
  background: var(--color-white);
  border-radius: var(--radius-md);
  overflow: hidden;
  box-shadow: var(--shadow-soft);
}

.routine-card-header {
  padding: 2rem;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.6rem;
  text-align: center;
}

.routine-card-header--morning {
  background: linear-gradient(135deg, #fff3e6, #fde8cc);
}

.routine-card-header--night {
  background: linear-gradient(135deg, #2c2340, #3d3057);
}

.routine-card-header--morning i { color: #e8a040; font-size: 1.8rem; }
.routine-card-header--night i   { color: #b0a0d0; font-size: 1.8rem; }

.routine-card-header--morning h3 { color: var(--color-text); }
.routine-card-header--night h3   { color: var(--color-white); }

.routine-time {
  font-size: 0.74rem;
  letter-spacing: 0.12em;
}

.routine-card-header--morning .routine-time { color: var(--color-text-sub); }
.routine-card-header--night .routine-time   { color: rgba(255,255,255,0.55); }

.routine-card-body {
  padding: 1.8rem;
}

.routine-list {
  margin-bottom: 1.2rem;
  display: flex;
  flex-direction: column;
  gap: 0.6rem;
}

.routine-list li {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  font-size: 0.86rem;
  color: var(--color-text-sub);
}

.routine-list i {
  color: var(--color-primary);
  font-size: 0.7rem;
}

.routine-desc {
  font-size: 0.83rem;
  color: var(--color-text-sub);
  line-height: 1.9;
  padding-top: 1rem;
  border-top: 1px solid var(--color-border);
}

/* ---- KNOWLEDGE ---- */
.product-knowledge {
  background: var(--color-cream);
  padding: var(--space-xl) 0;
}

.knowledge-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 1.5rem;
}

.knowledge-card {
  display: flex;
  gap: 1.4rem;
  padding: 1.8rem;
  background: var(--color-white);
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-soft);
  align-items: flex-start;
}

.knowledge-card-icon {
  width: 48px; height: 48px;
  background: var(--color-cream);
  border-radius: var(--radius-sm);
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
}

.knowledge-card-icon i {
  font-size: 1.2rem;
  color: var(--color-primary);
}

.knowledge-card-body .tag {
  margin-bottom: 0.6rem;
}

.knowledge-card-body h3 {
  font-size: 0.95rem;
  margin-bottom: 0.6rem;
  color: var(--color-text);
}

.knowledge-card-body p {
  font-size: 0.83rem;
  color: var(--color-text-sub);
  line-height: 1.9;
}

/* ==========================================
   RESPONSIVE
   ========================================== */
@media (max-width: 900px) {
  .method-grid     { grid-template-columns: 1fr; }
  .routine-grid    { grid-template-columns: 1fr; }
  .knowledge-grid  { grid-template-columns: 1fr; }
}

@media (max-width: 700px) {
  .howto-steps::before { left: 44px; }
  .howto-step { gap: 1.2rem; }
  .knowledge-card { flex-direction: column; gap: 1rem; }
}