/* Premium Slate & Royal Blue Theme variables */
:root {
    --app-bg: #0F172A; 
    --panel-bg: #1E293B; 
    --primary-blue: #2563EB; 
    --primary-blue-hover: #1D4ED8; 
    --border-color: #334155;
    --text-main: #F8FAFC;
    --text-muted: #94A3B8;
    --shadow-elevation: 0 4px 20px rgba(0, 0, 0, 0.4);
}

/* APP FRAME LAYOUT */
body {
    background-color: var(--app-bg);
    margin: 0; padding: 0;
    color: var(--text-main);
    display: flex; flex-direction: column;
    height: 100vh; overflow: hidden; 
}

#ambient-canvas {
    position: fixed; top: 0; left: 0; width: 100vw; height: 100vh; z-index: 0; pointer-events: none;
}

/* HEADER */
.unified-workspace-header {
    background-color: rgba(15, 23, 42, 0.85); 
    backdrop-filter: blur(12px); -webkit-backdrop-filter: blur(12px);
    border-bottom: 1px solid rgba(255, 255, 255, 0.08);
    padding: 0.6rem 1.5rem;
    display: flex; justify-content: space-between; align-items: center;
    flex-wrap: nowrap; gap: 1.5rem;
    box-shadow: var(--shadow-elevation); z-index: 100; flex-shrink: 0;
    overflow-x: auto; scrollbar-width: none; 
}
.unified-workspace-header::-webkit-scrollbar { display: none; }

.header-left-group { display: flex; align-items: center; gap: 1rem; flex-shrink: 0; }

.back-btn {
    background-color: rgba(255, 255, 255, 0.1); color: #ffffff;
    border: 1px solid rgba(255, 255, 255, 0.15); padding: 0.4rem 1.2rem;
    border-radius: 6px; cursor: pointer; font-weight: 500;
    font-family: 'Poppins', sans-serif; font-size: 0.9rem;
    display: flex; align-items: center; justify-content: center; gap: 0.4rem; transition: all 0.2s ease; white-space: nowrap;
}
.back-btn:hover { background-color: rgba(255, 255, 255, 0.2); border-color: rgba(255, 255, 255, 0.3); transform: translateY(-1px); }

.header-right-group { display: flex; align-items: center; gap: 0.6rem; flex-shrink: 0; justify-content: flex-end; flex-grow: 1; }

.chapter-capsule {
    padding: 0.4rem 1.2rem; border-radius: 6px; border: 1px solid var(--border-color);
    background-color: var(--panel-bg); color: var(--text-main);
    font-family: 'Poppins', sans-serif; font-size: 0.9rem; font-weight: 500;
    white-space: nowrap; display: flex; align-items: center;
}

.app-btn {
    background-color: var(--primary-blue); color: #ffffff; border: none;
    padding: 0.4rem 1.1rem; border-radius: 6px; cursor: pointer; font-weight: 500;
    font-family: 'Poppins', sans-serif; font-size: 0.9rem;
    display: flex; align-items: center; justify-content: center; gap: 0.4rem; transition: all 0.2s ease; white-space: nowrap;
}
.app-btn:hover { background-color: var(--primary-blue-hover); transform: translateY(-1px); }
.app-btn-outline { background-color: transparent; color: var(--text-main); border: 1px solid var(--border-color); }
.app-btn-outline:hover { background-color: var(--panel-bg); border-color: var(--primary-blue); color: var(--primary-blue); }
.app-btn-yt { background-color: #DC2626; color: #ffffff; }
.app-btn-yt:hover { background-color: #B91C1C; }
.app-btn-yt.mild { background-color: var(--panel-bg); border: 1px solid var(--border-color); color: var(--text-muted); opacity: 0.7; }
.app-btn-yt.mild:hover { background-color: var(--border-color); color: var(--text-main); transform: none; }

/* HIDE MOBILE ELEMENTS ON DESKTOP */
.mobile-timer, .mobile-eyes { display: none !important; }
.hide-on-mobile { display: flex; }

/* MAIN CONTENT */
.main-content { background-color: #000000; flex-grow: 1; position: relative; width: 100%; margin: 0; padding: 0; z-index: 10; }
.pdf-viewer-container { position: absolute; top: 0; left: 0; right: 0; bottom: 0; display: flex; flex-direction: column; }
.pdf-viewer-container iframe { width: 100%; height: 100%; border: none; }

.pdf-loading-overlay {
    position: absolute; top: 0; left: 0; right: 0; bottom: 0; background-color: var(--app-bg); z-index: 10;
    display: flex; flex-direction: column; justify-content: center; align-items: center; gap: 1.5rem; transition: opacity 0.5s ease, visibility 0.5s ease;
}
.loading-spinner-ring { width: 60px; height: 60px; border: 5px solid var(--border-color); border-top: 5px solid var(--primary-blue); border-radius: 50%; animation: spin 1s infinite; }
.loading-text { font-family: 'Poppins', sans-serif; font-weight: 500; color: var(--text-main); letter-spacing: 1px; animation: pulse 1.5s infinite; }

/* FOOTER */
.unified-workspace-footer {
    background-color: rgba(15, 23, 42, 0.85); backdrop-filter: blur(12px); border-top: 1px solid rgba(255, 255, 255, 0.08);
    padding: 0.6rem 1.5rem; display: flex; justify-content: space-between; align-items: center; z-index: 100; flex-shrink: 0;
    font-size: 0.85rem; color: var(--text-muted); box-shadow: 0 -4px 20px rgba(0, 0, 0, 0.4);
}
.footer-tools { display: flex; align-items: center; gap: 1.2rem; }
.motivation-text { color: var(--text-main); font-weight: 500; margin-right: 0.5rem; transition: opacity 0.3s ease; }
.timer-display {
    font-family: 'Poppins', monospace; font-weight: 600; font-size: 1rem; color: var(--text-main); letter-spacing: 1px;
    background-color: rgba(255, 255, 255, 0.05); padding: 0.2rem 0.8rem; border-radius: 4px; border: 1px solid rgba(255, 255, 255, 0.1);
}

/* EYES */
.tracking-eyes-container {
    --eye-size: 20px; --pupil-size: calc(var(--eye-size) * 0.4); --border-width: calc(var(--eye-size) * 0.07); --eye-gap: calc(var(--eye-size) * 0.25);
    display: inline-flex; gap: var(--eye-gap);
}
.eye-ball { width: var(--eye-size); height: var(--eye-size); background: #ffffff; border-radius: 50%; border: var(--border-width) solid var(--app-bg); position: relative; overflow: hidden; }
.eye-ball::before { content: ''; position: absolute; top: 10%; left: 12%; width: 25%; height: 12%; background: rgba(255, 255, 255, 0.8); border-radius: 50%; z-index: 2; }
.pupil { width: var(--pupil-size); height: var(--pupil-size); background: var(--app-bg); border-radius: 50%; position: absolute; top: 50%; left: 50%; transform: translate(-50%, -50%); will-change: transform; }

/* MODALS & TOASTS */
.yt-modal-overlay { position: fixed; top: 0; left: 0; right: 0; bottom: 0; background-color: rgba(15, 23, 42, 0.85); backdrop-filter: blur(5px); z-index: 2000; display: flex; justify-content: center; align-items: center; opacity: 0; visibility: hidden; }
.yt-modal-overlay.active { opacity: 1; visibility: visible; }
.yt-modal-card { 
    background-color: #ffffff; 
    color: #0f172a; /* FIXED: Added dark text color for visibility */
    border-radius: 16px; 
    padding: 2.5rem 2rem; 
    width: 90%; 
    max-width: 400px; 
    text-align: center; 
    transform: translateY(20px); 
    transition: transform 0.3s ease; 
}
.yt-modal-overlay.active .yt-modal-card { transform: translateY(0); }
.modal-icon-wrapper { width: 80px; height: 80px; background-color: #FEF2F2; border-radius: 50%; display: flex; justify-content: center; align-items: center; margin: 0 auto 1.5rem auto; position: relative; }
.modal-icon-wrapper svg { width: 36px; height: 36px; color: #DC2626; fill: #DC2626; }
.modal-actions { display: flex; gap: 1rem; justify-content: center; margin-top: 2rem;}
.m-btn { flex: 1; padding: 0.8rem 1rem; border-radius: 8px; font-weight: 600; font-family: 'Poppins', sans-serif; font-size: 1rem; cursor: pointer; border: none;}
.m-btn-outline { background: #f1f5f9; color: #334155; }
.m-btn-solid { background: #DC2626; color: #ffffff; }

.status-toast { position: fixed; bottom: 80px; left: 50%; transform: translateX(-50%) translateY(20px); background-color: #F59E0B; color: #ffffff; padding: 0.8rem 1.5rem; border-radius: 50px; font-family: 'Poppins', sans-serif; opacity: 0; visibility: hidden; transition: all 0.3s ease; z-index: 3000; pointer-events: none; white-space: nowrap; }
.status-toast.show { opacity: 1; visibility: visible; transform: translateX(-50%) translateY(0); }

@keyframes spin { 0% { transform: rotate(0deg); } 100% { transform: rotate(360deg); } }

/* TABLET & MOBILE ADJUSTMENTS (Under 850px) */
@media (max-width: 850px) {
    /* 1. HIDE DESKTOP FOOTER */
    .unified-workspace-footer { display: none !important; }

    /* 2. RESTRUCTURE HEADER FOR MOBILE */
    .unified-workspace-header {
        padding: 0.5rem 0.6rem;
        gap: 0.5rem;
        background-color: #051024; 
        border-bottom: none;
    }

    .chapter-capsule { display: none !important; }
    .hide-on-mobile { display: none !important; } /* Hides Fullscreen button */

    .header-left-group { gap: 0.4rem; }
    
    .header-right-group {
        gap: 0.4rem;
        justify-content: flex-end; /* Keeps items pushed to the right */
        flex-grow: 1;
    }

    /* Convert buttons to sleek squares */
    .app-btn, .back-btn { 
        font-size: 0; 
        padding: 0; 
        width: 38px; height: 38px;
        border-radius: 8px;
        gap: 0; 
        justify-content: center; align-items: center;
        background-color: rgba(255, 255, 255, 0.08); 
        border: 1px solid rgba(255, 255, 255, 0.1);
    }
    .app-btn svg, .back-btn svg { width: 18px; height: 18px; }

    .app-btn-yt { background-color: #DC2626 !important; border: none; }

    /* 3. SHOW MOBILE HEADER TOOLS */
    .mobile-timer {
        display: block !important;
        font-size: 0.85rem;
        padding: 0.25rem 0.6rem;
        background-color: rgba(255, 255, 255, 0.08); 
        border: none;
        border-radius: 6px;
        margin-left: 0.5rem;
    }

    .mobile-eyes {
        display: inline-flex !important;
        --eye-size: 18px;
        align-items: center;
    }
}