/* ====================================================
   PROJECTS SECTION — Codegrid Otsuka 3D Cards
   3D flipping cubes with parallax cursor tilt
   ==================================================== */

#projects {
  position: relative;
  background: var(--clr-bg);
  color: var(--clr-text);
  min-height: 100vh;
  overflow: hidden;
  display: flex;
  flex-direction: column;
  align-items: center;
  padding: clamp(3rem, 6vh, 5rem) 0 clamp(4rem, 8vh, 6rem);
  border-top: 1px solid var(--clr-border);
}

.projects__header {
  flex-shrink: 0;
  text-align: center;
  z-index: 20;
  margin-bottom: clamp(2rem, 5vh, 3.5rem);
  padding: 0 1.5rem;
}

.projects__label {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.25em;
  text-transform: uppercase;
  color: var(--clr-red);
  margin-bottom: var(--sp-2);
}

.projects__header h2 {
  font-family: var(--font-display);
  font-size: clamp(2.2rem, 5vw, 4rem);
  font-weight: 700;
  letter-spacing: -0.03em;
  color: var(--clr-text);
  line-height: 1.1;
}

.projects__header span {
  color: var(--clr-red);
}

.projects__sub {
  font-family: var(--font-body);
  font-size: var(--text-sm);
  color: var(--clr-text-muted);
  margin-top: var(--sp-2);
}

/* Stage & Track */
.projects__stage {
  position: relative;
  width: 100%;
  max-width: 100vw;
  overflow-x: auto;
  overflow-y: visible;
  padding: 2.5rem 1.5rem 3.5rem;
  scrollbar-width: thin;
  scrollbar-color: var(--clr-red) transparent;
  -webkit-overflow-scrolling: touch;
  cursor: grab;
}

.projects__stage:active {
  cursor: grabbing;
}

.projects__track {
  display: flex;
  gap: clamp(2rem, 4vw, 3.5rem);
  width: max-content;
  margin: 0 auto;
  padding: 0 clamp(1rem, 4vw, 3rem);
  perspective: 2500px;
}

/* Otsuka 3D Card */
.otsuka-card {
  --card-width: 320px;
  --card-height: 440px;
  --card-depth: 320px;

  width: var(--card-width);
  height: var(--card-height);
  perspective: 2000px;
  flex-shrink: 0;
  position: relative;
  user-select: none;
}

.otsuka-cube {
  position: relative;
  width: 100%;
  height: 100%;
  transform-style: preserve-3d;
  cursor: pointer;
  transform: translateZ(calc(var(--card-depth) / -2));
  will-change: transform;
}

/* Face common */
.otsuka-face {
  position: absolute;
  backface-visibility: hidden;
  box-sizing: border-box;
}

/* Front and Back */
.otsuka-face-front,
.otsuka-face-back {
  width: var(--card-width);
  height: var(--card-height);
  background: var(--clr-bg);
  border: 1px solid var(--clr-border);
  border-radius: var(--radius-sm);
  display: flex;
  flex-direction: column;
  padding: 1.5rem;
  box-shadow: 0 10px 30px rgba(0, 0, 0, 0.08);
}

.otsuka-face-front {
  transform: translateZ(calc(var(--card-depth) / 2));
}

.otsuka-face-back {
  transform: rotateX(180deg) translateZ(calc(var(--card-depth) / 2));
  background: #0d0d0d;
  color: #ffffff;
  border-color: #262626;
  justify-content: space-between;
}

/* Side faces */
.otsuka-face-right,
.otsuka-face-left {
  width: var(--card-depth);
  height: var(--card-height);
  left: calc((var(--card-width) - var(--card-depth)) / 2);
  background: #ececec;
  border: 1px solid #d4d4d4;
}

.otsuka-face-top,
.otsuka-face-bottom {
  width: var(--card-width);
  height: var(--card-depth);
  top: calc((var(--card-height) - var(--card-depth)) / 2);
  background: #dfdfdf;
  border: 1px solid #c8c8c8;
}

.otsuka-face-right {
  transform: rotateY(90deg) translateZ(calc(var(--card-width) / 2));
}

.otsuka-face-left {
  transform: rotateY(-90deg) translateZ(calc(var(--card-width) / 2));
}

.otsuka-face-top {
  transform: rotateX(90deg) translateZ(calc(var(--card-height) / 2));
  background: linear-gradient(to bottom, #f40c3f, #dfdfdf);
}

.otsuka-face-bottom {
  transform: rotateX(-90deg) translateZ(calc(var(--card-height) / 2));
}

/* Card Content: Front */
.card-top {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 1rem;
}

.card-cat {
  font-family: var(--font-mono);
  font-size: 0.7rem;
  letter-spacing: 0.15em;
  text-transform: uppercase;
  color: var(--clr-red);
  font-weight: 600;
}

.card-index {
  font-family: var(--font-mono);
  font-size: 0.85rem;
  font-weight: 700;
  color: var(--clr-text-muted);
}

.card-thumb-wrap {
  width: 100%;
  height: 180px;
  border-radius: var(--radius-sm);
  overflow: hidden;
  background: #f0f0f0;
  border: 1px solid var(--clr-border);
  margin-bottom: 1.25rem;
}

.card-thumb {
  width: 100%;
  height: 100%;
  object-fit: cover;
  object-position: center top;
  display: block;
}

.card-title {
  font-family: var(--font-display);
  font-size: 1.5rem;
  font-weight: 700;
  letter-spacing: -0.02em;
  color: var(--clr-text);
  margin-bottom: 0.5rem;
  line-height: 1.15;
}

.card-meta {
  display: flex;
  align-items: flex-end;
  justify-content: space-between;
  gap: 0.5rem;
  margin-top: auto;
}

.card-desc {
  font-family: var(--font-body);
  font-size: 0.85rem;
  line-height: 1.45;
  color: var(--clr-text-muted);
}

.card-arrow {
  width: 1.75rem;
  height: 1.75rem;
  color: var(--clr-red);
  flex-shrink: 0;
  transition: transform var(--dur-base) var(--ease-expo);
}

.otsuka-card:hover .card-arrow {
  transform: translateX(4px);
}

/* Card Content: Back */
.card-back-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  border-bottom: 1px solid #222;
  padding-bottom: 0.75rem;
}

.card-back-title {
  font-family: var(--font-display);
  font-size: 1.35rem;
  font-weight: 700;
  color: #ffffff;
}

.card-back-desc {
  font-family: var(--font-body);
  font-size: 0.9rem;
  line-height: 1.6;
  color: #b0b0b0;
  margin: 1rem 0;
}

.card-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
  margin-bottom: 1.5rem;
}

.card-tag {
  font-family: var(--font-mono);
  font-size: 0.68rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--clr-red);
  background: rgba(244, 12, 63, 0.12);
  border: 1px solid rgba(244, 12, 63, 0.35);
  border-radius: var(--radius-full);
  padding: 3px 10px;
}

.card-github-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.6rem;
  width: 100%;
  padding: 0.75rem 1rem;
  background: var(--clr-red);
  color: #ffffff;
  font-family: var(--font-mono);
  font-size: 0.8rem;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  font-weight: 700;
  border-radius: var(--radius-sm);
  text-decoration: none;
  transition: background var(--dur-base) ease, transform var(--dur-base) ease;
}

.card-github-btn:hover {
  background: #c0082e;
  transform: translateY(-2px);
}

/* Navigation hint */
.projects__hint {
  display: flex;
  align-items: center;
  gap: var(--sp-3);
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  color: var(--clr-text-muted);
  letter-spacing: 0.12em;
  text-transform: uppercase;
  margin-top: 1rem;
}

.projects__hint span {
  color: var(--clr-red);
}

/* Responsive */
@media (max-width: 768px) {
  .otsuka-card {
    --card-width: 290px;
    --card-height: 420px;
    --card-depth: 290px;
  }
}

@media (max-width: 480px) {
  .otsuka-card {
    --card-width: 260px;
    --card-height: 380px;
    --card-depth: 260px;
  }
  .card-title {
    font-size: 1.3rem;
  }
  .card-desc {
    font-size: 0.8rem;
  }
}