@media (max-width: 768px) {
    header {
        position: relative;
        border-bottom: 1px solid rgba(43, 37, 30, 0.1);
        margin-bottom: 2.5rem;
    }
    
    main {
        margin-top: 0;
    }
    
    .nav-menu {
        position: fixed;
        top: 0;
        right: -100%;
        width: 60%;
        max-width: 300px;
        height: 100vh;
        background: var(--paper-warm);
        flex-direction: column;
        justify-content: center;
        align-items: center;
        gap: 3rem;
        transition: right 0.4s cubic-bezier(0.77, 0, 0.175, 1);
        z-index: 1000;
        border-left: 1px solid var(--paper-dark);
        box-shadow: -10px 0 30px rgba(0,0,0,0.1);
    }
    
    .nav-menu.active {
        right: 0;
    }

    .mobile-menu-toggle {
        display: flex;
    }

    .mobile-menu-toggle.active span:nth-child(1) {
        transform: translateY(8px) rotate(45deg);
    }
    .mobile-menu-toggle.active span:nth-child(2) {
        opacity: 0;
    }
    .mobile-menu-toggle.active span:nth-child(3) {
        transform: translateY(-8px) rotate(-45deg);
    }

    .nav-link {
        font-size: 1.5rem;
        font-weight: 700;
    }

    .ghost-id-display {
        font-size: 1.1rem;
    }
}

@media (max-width: 600px) {
    main {
        padding: 0 0.5rem;
    }
    .diary-card {
        padding: 2.5rem 1.5rem 2.5rem 3.5rem;
        min-height: 85vh;
        margin: 0 0 2rem 0;
        border-radius: 2px 10px 10px 2px;
        border-left: 15px solid rgba(43, 37, 30, 0.15); /* Historical notebook spine binding */
        border-right: 1px solid var(--paper-dark);
        border-top: 1px solid var(--paper-dark);
        border-bottom: 1px solid var(--paper-dark);
        box-shadow: inset 8px 0 12px rgba(0,0,0,0.05), 5px 5px 15px rgba(0,0,0,0.08); /* Spine depth */
    }
    .diary-card::after {
        left: 2.8rem;
        width: 2px;
        background: rgba(139, 28, 28, 0.3); /* Crimson margin ink */
    }
    .card-text {
        font-size: 1.15rem;
        line-height: 32px; /* Rigidly locked to background ruled lines */
    }
    .diary-header-text {
        font-size: 0.9rem !important;
    }
    .diary-header-container {
        margin-bottom: 1.5rem !important;
    }
    .header-line {
        max-width: 60px !important;
    }
}

@media (max-width: 480px) {
    header {
        padding: 1rem;
    }
    .logo {
        font-size: 1.25rem;
    }
    .emoji-btn {
        width: 40px;
        height: 40px;
        font-size: 1.25rem;
    }
}
@media (min-width: 769px) {
    #nav-access-btn, #nav-logout-btn {
        position: fixed;
        bottom: 2rem;
        right: 2rem;
        z-index: 1000;
        background-color: var(--paper-warm);
        padding: 0.8rem 1.2rem;
        border: 1px solid var(--paper-dark);
        border-radius: 4px;
        box-shadow: var(--shadow-1);
        text-transform: uppercase;
        font-size: 0.8rem;
        letter-spacing: 0.1em;
        font-weight: 700;
    }

    #nav-access-btn:hover, #nav-logout-btn:hover {
        background-color: var(--paper-dark);
        transform: translateY(-2px);
    }

    #nav-logout-btn {
        color: var(--accent) !important; /* Use theme accent color */
    }
}