/* ============================================
   CHAPTER 3: TENSION
   Theme: Something is chosen. Discerning near differences.
   Scope: body[data-chapter="tension"]
   ============================================ */

body[data-chapter="tension"] {
    --tension-bg: #07070A;
    --tension-surface: #0E0F14;
    --tension-gold: #FFC857;
    --tension-cyan: #00F0FF;
    --tension-magenta: #FF4FA3;
    --tension-yellow: #FFE600;
    --tension-ink: #D8DBE2;
    --tension-mute: #5A5F6E;
    --tension-border: rgba(216, 219, 226, 0.10);

    background: var(--tension-bg);
    color: var(--tension-ink);
    overflow-y: auto;
    overflow-x: hidden;
}

body[data-chapter="tension"]::before {
    content: "";
    position: fixed;
    inset: 0;
    pointer-events: none;
    z-index: 0;
    background:
        radial-gradient(ellipse at 50% 30%, rgba(255, 200, 87, 0.025) 0%, transparent 60%),
        radial-gradient(ellipse at 50% 80%, rgba(255, 79, 163, 0.02) 0%, transparent 50%);
}

.chapter-tension {
    position: relative;
    width: 100%;
    z-index: 1;
}

/* ============================================
   HEADER
   ============================================ */
.tension-head {
    width: min(1040px, 90vw);
    margin: 0 auto;
    padding-top: clamp(6rem, 12vh, 9rem);
    padding-bottom: clamp(2rem, 5vh, 4rem);
}

.tension-meta {
    display: flex;
    align-items: center;
    gap: 1em;
    font-family: 'JetBrains Mono', monospace;
    font-size: var(--size-meta);
    letter-spacing: 0.28em;
    color: var(--tension-mute);
    text-transform: uppercase;
    margin-bottom: 0.8rem;
}

.tension-meta .meta-index {
    color: var(--tension-gold);
    font-weight: 500;
}

.tension-meta .meta-divider {
    display: inline-block;
    width: 24px;
    height: 1px;
    background: var(--tension-mute);
}

.tension-title {
    font-family: var(--font-display);
    font-size: clamp(2rem, 5vw, 4.2rem);
    line-height: 0.95;
    letter-spacing: 0.02em;
    color: var(--tension-ink);
    text-transform: uppercase;
}

/* ============================================
   PAIRS STAGE
   ============================================ */
.tension-pairs-wrap {
    display: flex;
    flex-direction: column;
    gap: clamp(4rem, 10vh, 8rem);
    padding-bottom: clamp(5rem, 12vh, 9rem);
}

.tension-pair-stage {
    width: min(1040px, 90vw);
    margin: 0 auto;
    display: flex;
    flex-direction: column;
    gap: 1.2rem;
}

.tension-pair-header {
    display: flex;
    justify-content: space-between;
    align-items: baseline;
    font-family: 'JetBrains Mono', monospace;
    font-size: 0.72rem;
    letter-spacing: 0.2em;
    color: var(--tension-mute);
    text-transform: uppercase;
    padding: 0 0.25rem;
}

.tension-pair-tag {
    color: var(--tension-gold);
}

/* 対置フィールド */
.tension-fields {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 1.5rem;
    position: relative;
}

.tension-field {
    position: relative;
    aspect-ratio: 16 / 10;
    background: var(--tension-surface);
    border: 1px solid var(--tension-border);
    overflow: hidden;
    cursor: pointer;
    transition:
        border-color 240ms var(--ease-cut),
        transform 240ms var(--ease-cut);
}

.tension-field:hover {
    border-color: rgba(255, 200, 87, 0.4);
    transform: translateY(-2px);
}

.tension-field.is-selected {
    border-color: var(--tension-gold);
    box-shadow: 0 0 20px rgba(255, 200, 87, 0.15);
}

.tension-canvas {
    position: absolute;
    inset: 0;
    width: 100%;
    height: 100%;
    display: block;
}

.tension-media {
    position: absolute;
    inset: 0;
    width: 100%;
    height: 100%;
    object-fit: cover;
    filter: contrast(1.05);
}

.field-label {
    position: absolute;
    bottom: 12px;
    right: 14px;
    font-family: 'JetBrains Mono', monospace;
    font-size: 0.65rem;
    letter-spacing: 0.2em;
    color: var(--tension-mute);
    text-transform: uppercase;
    pointer-events: none;
    transition: color 200ms;
}

.tension-field:hover .field-label,
.tension-field.is-selected .field-label {
    color: var(--tension-gold);
}

/* ============================================
   TENSION FOOTER
   ============================================ */

/* Detail_R: keep the existing fields and study cards; add one linked preview. */
.tension-project-stage .tension-pair-tag {
    font: inherit;
    margin: 0;
}

.tension-project-link {
    display: block;
    aspect-ratio: 16 / 9;
}

.tension-project-link .tension-media {
    object-fit: contain;
    filter: none;
}

.tension-project-link .field-label {
    color: var(--tension-ink);
    padding: 0.55em 0.75em;
    background: rgba(7, 7, 10, 0.85);
}

.tension-project-link:hover .field-label,
.tension-project-link:focus-visible .field-label {
    color: var(--tension-gold);
}

.tension-project-note {
    font-size: 0.8rem;
    line-height: 1.9;
    letter-spacing: 0.04em;
    color: #A1A5AE;
}

.tension-footer {
    position: relative;
    width: 100%;
    padding: clamp(3rem, 8vh, 6rem) var(--gutter) clamp(4rem, 10vh, 7rem);
    border-top: 1px solid var(--tension-border);
    background: rgba(7, 7, 10, 0.8);
}

.tension-footer-inner {
    width: min(1040px, 90vw);
    margin: 0 auto;
    display: flex;
    justify-content: space-between;
    align-items: flex-end;
    flex-wrap: wrap;
    gap: 2rem;
}

.tension-summary {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.tension-summary .sum-num {
    font-family: 'JetBrains Mono', monospace;
    font-size: 0.75rem;
    letter-spacing: 0.2em;
    color: var(--tension-mute);
}

.tension-summary .sum-text {
    font-family: var(--font-body);
    font-size: clamp(1rem, 1.6vw, 1.3rem);
    font-weight: 300;
    letter-spacing: 0.08em;
    color: var(--tension-ink);
}

/* ============================================
   RESPONSIVE
   ============================================ */
@media (max-width: 720px) {
    body[data-chapter="tension"] .stage-mark span:last-child {
        display: none;
    }

    .tension-head {
        padding-top: 10rem;
    }

    .tension-fields {
        grid-template-columns: 1fr;
        gap: 1rem;
    }

    .tension-field {
        aspect-ratio: 16 / 9;
    }

    .tension-footer-inner {
        flex-direction: column;
        align-items: flex-start;
        gap: 1.5rem;
    }
}