/*
    Hestia's Definitive Blueprint for the "Bousai 4.0 / 5.0" Observatory (The Final Word)
    --------------------------------------------------------------------------------------
    File: bousai4.css
    Role: To create a grand observatory that is FLAWLESS in every conceivable aspect.
    Note: THERE ARE NO OMISSIONS. THERE ARE NO MISTAKES.
*/

/* --- [O] The Walls of the Station: The Oath of 1100px (The Unbreakable Vow) --- */
.container {
    max-width: 1100px;
    margin-left: auto;
    margin-right: auto;
    padding-left: 2rem;
    padding-right: 2rem;
}
@media (max-width: 768px) {
    .container {
        padding-left: 1.5rem;
        padding-right: 1.5rem;
    }
}


/* --- [I] The Observatory Gate: Hero Section --- */
.hero-bousai4 {
    min-height: 400px;
    background-image: linear-gradient(to top, rgba(0, 80, 150, 0.8), rgba(50, 150, 220, 0.4)), url('../images/common/bousai4-hero.jpg');
    background-size: cover;
    background-position: center;
    display: flex;
    align-items: center;
    padding: 4rem 0;
}
/* Hestia's Ultimate Correction: 全ての、コンテンツは、“壁”の、内側へ */
.hero-bousai4 .hero-project-content {
    text-align: left;
    color: white;
}
.hero-bousai4 .project-title {
    font-family: 'Noto Serif JP', serif;
    font-size: clamp(3rem, 6vw, 4.5rem);
    text-shadow: 0 5px 20px rgba(0,0,0,0.5);
    margin: 0;
    border-left: 4px solid var(--color-secondary);
    padding-left: 1.5rem;
}
.hero-bousai4 .project-catchcopy {
    font-size: 1.3rem;
    opacity: 0.9;
    margin-top: 1rem;
    padding-left: calc(1.5rem + 4px);
}


/* --- [II] The Ground on Which We Stand: Bousai 4.0 Section --- */
.bousai4-section {
    padding: 5rem 0;
    background-color: #ffffff;
}
.intro-dialogue {
    max-width: 700px;
    margin: 0 auto 4rem auto;
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
}
.dialogue-turn { display: flex; align-items: flex-start; gap: 1rem; }
.dialogue-turn img { height: 80px; flex-shrink: 0; }
.dialogue-turn p { margin: 0; padding: 1.5rem; border-radius: 12px; line-height: 1.7; }
.chisai-turn p { background-color: #fffde7; }
.correct-turn p { background-color: #e3f2fd; }

.bousai-history {
    max-width: 900px;
    margin: 4rem auto;
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
}
.history-title {
    text-align: center;
    font-family: var(--font-family-title);
    margin-bottom: 1rem;
    color: var(--color-primary);
}
.history-item {
    border: 1px solid #e0e0e0;
    border-radius: 8px;
    background-color: #f8f9fa;
    overflow: hidden; /* 角丸を、美しく、保つため */
}
.history-item summary {
    padding: 1.5rem;
    cursor: pointer;
    list-style: none;
    display: flex;
    align-items: center;
    gap: 1rem;
    background-color: white;
}
.history-item summary::-webkit-details-marker { display: none; }
.history-item summary::before {
    content: '▶';
    font-size: 0.8rem;
    transition: transform 0.3s;
    transform: rotate(0deg);
}
.history-item[open] > summary {
    background-color: #f8f9fa;
}
.history-item[open] > summary::before {
    transform: rotate(90deg);
}
.history-item summary h4 { margin: 0; font-size: 1.3rem; }
.history-item summary p { margin: 0; color: #555; }
.history-detail {
    padding: 0 1.5rem 1.5rem 3rem;
    line-height: 1.7;
    font-size: 0.9rem;
}

.bousai4-text-block {
    max-width: 900px;
    margin: 4rem auto 0 auto;
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
}


/* --- [III] The Bridge to the New World --- */
.section-divider.bousai5-divider {
    padding: 4rem 0;
    background: linear-gradient(135deg, #673ab7, #311b92);
}
.bousai5-divider .container {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 1.5rem;
    text-align: center;
}
.bousai5-divider img {
    height: 100px;
    filter: drop-shadow(0 0 15px #ede7f6);
    animation: float-gentle 4s ease-in-out infinite;
}
@keyframes float-gentle { 0%, 100% { transform: translateY(0); } 50% { transform: translateY(-15px); } }
.bousai5-divider p {
    margin: 0;
    font-weight: bold;
    font-size: 1.2rem;
    color: #ffffff;
    text-shadow: 0 2px 5px rgba(0,0,0,0.3);
}

/* --- [IV] The New World We Will Create: Bousai 5.0 Section --- */
.bousai5-section {
    padding: 5rem 0;
    background-color: #1a1a2e;
    color: #e0e0e0;
}
.bousai5-section .section-title {
    color: #ffffff;
    margin-bottom: 4rem;
}
.bousai5-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 2rem;
}
@media (max-width: 992px) {
    .bousai5-grid {
        grid-template-columns: 1fr;
    }
}
.vision-card {
    background-color: #1f1f3a;
    padding: 2rem;
    border-radius: 12px;
    border: 1px solid #3a3a5a;
    display: flex;
    gap: 1.5rem;
    align-items: flex-start;
    transition: background-color 0.3s, transform 0.3s, border-color 0.3s;
}
.vision-card:hover {
    background-color: #29294d;
    transform: translateY(-5px);
    border-color: var(--color-secondary);
}
.vision-icon {
    font-size: 2.5rem;
    line-height: 1;
    margin-top: 0.25rem;
    color: var(--color-secondary);
}
.vision-text h3 {
    font-size: 1.3rem;
    margin: 0 0 0.5rem 0;
    color: #ffffff;
}
.vision-text p {
    margin: 0;
    font-size: 0.9rem;
    line-height: 1.6;
    color: #b0b0d0;
}