:root {
    --bg-main: #f4f4f5;
    --bg-secondary: #ffffff;
    --border-color: #e4e4e7;
    --text-primary: #18181b;
    --text-secondary: #71717a;
    --bubble-other-bg: #e5e5ea;
    --bubble-other-text: #1d2129; 
    --shadow-color: rgba(0,0,0,0.1);

    --text-accent: #007aff;
    --bubble-me: #007aff;
    --bubble-me-text: #ffffff;
    --new-message-highlight: #fffbe6; 
    --message-highlight-glow: #fdba74;
    --success-color: #22c55e;
    --danger-color: #ef4444;
    --gallery-item-size: 90px;
    --font-main: 'Inter', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
}

* { box-sizing: border-box; margin: 0; padding: 0; }
html { font-family: var(--font-main); }
body { -webkit-font-smoothing: antialiased; -moz-osx-font-smoothing: grayscale; overflow: hidden; background-color: #d1d5db; }

#loading-overlay {
    position: fixed;
    inset: 0;
    z-index: 9999;
    background-color: rgba(0, 0, 0, 0.5);
    backdrop-filter: blur(4px);
    display: flex;
    justify-content: center;
    align-items: center;
    transition: opacity 0.3s ease-in-out;
}
.loading-visible {
    opacity: 1;
    pointer-events: auto;
}
.loading-hidden {
    opacity: 0;
    pointer-events: none;
}
#loading-overlay .spinner {
    width: 48px;
    height: 48px;
    border-width: 5px;
    border-left-color: #ffffff;
}

/* --- HLAVNÍ STRUKTURA --- */
#chat-app-container {
    position: fixed;
    top: 0; left: 0;
    width: 100%; height: 100dvh;
    z-index: 1000;
    display: flex;
    flex-direction: column;
    background-color: var(--bg-secondary);
}
.app-hidden { display: none !important; }

.page-container {
    display: flex;
    height: 100%;
    width: 100%;
    margin: 0 auto;
}
.chat-panel {
    display: flex;
    flex-direction: column;
    width: 100%;
    height: 100%;
    background-color: var(--bg-secondary);
    flex-grow: 1;
}
.gallery-panel-desktop { display: none; }

@media (min-width: 900px) {
    #chat-app-container { position: static; height: 100vh; flex-direction: row; }
    .page-container { display: grid; grid-template-columns: 1fr 1fr; }
    .chat-panel { border-right: 1px solid var(--border-color); }
    .gallery-panel-desktop { 
        display: grid;
        grid-template-rows: auto 1fr;
        background-color: var(--bg-main);
        min-height: 0;
    }
    #gallery-toggle-btn { display: none; }
}

/* --- HLAVIČKA --- */
#app-header { background-color: var(--bg-secondary); padding: 0.75rem 1rem; border-bottom: 1px solid var(--border-color); z-index: 10; flex-shrink: 0; display: flex; justify-content: space-between; align-items: center; }
.header-content { text-align: left; }
#app-header h1 { font-size: 1rem; font-weight: 600; color: var(--text-primary); }
.user-id-wrapper { font-size: 0.75rem; color: var(--text-secondary); }
#user-display-name { font-weight: 600; color: var(--text-primary); }
.header-buttons { display: flex; align-items: center; gap: 0.25rem; }
#gallery-toggle-btn, #info-toggle-btn, #notifications-toggle-btn { background: none; border: none; cursor: pointer; color: var(--text-secondary); padding: 0.5rem; display: flex; align-items: center; }

#notifications-toggle-btn.notifications-granted {
    color: var(--success-color);
}
#notifications-toggle-btn.notifications-denied {
    color: var(--danger-color);
}
.hidden { display: none !important; }

/* --- CHAT --- */
#chat-container-wrapper { position: relative; flex-grow: 1; overflow: hidden; }
#chat-container { position: absolute; inset: 0; overflow-y: auto; padding: 1rem; display: flex; flex-direction: column; gap: 0.75rem; background-color: var(--bg-main); }
@keyframes fadeIn { from { opacity: 0; transform: translateY(10px); } to { opacity: 1; transform: translateY(0); } }
.message-wrapper { display: flex; max-width: 80%; animation: fadeIn 0.3s ease-out; position: relative; }
.message-wrapper:hover .message-actions { opacity: 1; }
.message-wrapper.current-user { align-self: flex-end; }
.message-wrapper.other-user { align-self: flex-start; }
.message-bubble { padding: 0.6rem 1rem; border-radius: 1.25rem; max-width: 100%; word-wrap: break-word; position: relative; transition: background-color 0.5s ease, box-shadow 0.3s ease; }
.current-user .message-bubble { background-color: var(--bubble-me); color: var(--bubble-me-text); border-bottom-right-radius: 0.5rem; }
.other-user .message-bubble { background-color: var(--bubble-other-bg); color: var(--bubble-other-text); border-bottom-left-radius: 0.5rem; }
.message-sender { font-size: 0.8rem; font-weight: 600; margin-bottom: 0.25rem; }
.message-sender.clickable { cursor: pointer; text-decoration: underline; }
.current-user .message-sender { color: var(--bubble-me-text); }
.message-text { white-space: pre-wrap; line-height: 1.5; color: inherit; }
.message-image { display: block; max-width: 300px; width: 100%; border-radius: 0.8rem; margin-top: 0.5rem; cursor: pointer; }
@media (max-width: 600px) { .message-image { max-width: 200px; } }
.message-time { font-size: 0.7rem; text-align: right; opacity: 0.7; }
.other-user .message-time { opacity: 0.5; }

.message-bubble.new-message-marker.other-user {
    background-color: var(--new-message-highlight);
}
.new-messages-separator {
    width: 100%;
    text-align: center;
    border-bottom: 1px solid var(--text-accent);
    line-height: 0.1em;
    margin: 1rem 0;
}
.new-messages-separator span {
    background: var(--bg-main);
    padding: 0 10px;
    font-size: 0.8rem;
    color: var(--text-accent);
    font-weight: 500;
}

#loading-indicator, .empty-chat-msg, .error-msg, .empty-gallery-msg { text-align: center; margin: auto; color: var(--text-secondary); padding: 1rem; }
.error-msg { background-color: #fee2e2; color: #b91c1c; border-radius: 0.5rem; border: 1px solid #fecaca; }
.spinner { margin: 0 auto 0.5rem; width: 24px; height: 24px; border: 3px solid rgba(0,0,0,0.1); border-left-color: var(--text-accent); border-radius: 50%; animation: spin 1s linear infinite; }
@keyframes spin { to { transform: rotate(360deg); } }

#load-more-container {
    display: flex;
    justify-content: center;
    padding: 1rem 0;
}
#load-more-container.hidden {
    display: none;
}
#load-more-btn {
    background-color: var(--bg-secondary);
    border: 1px solid var(--border-color);
    color: var(--text-primary);
    padding: 0.5rem 1rem;
    border-radius: 1.5rem;
    cursor: pointer;
    font-weight: 500;
}
.spinner-small {
    width: 20px;
    height: 20px;
    border-width: 2px;
}
.spinner-small.hidden {
    display: none;
}


#scroll-to-bottom-btn {
    position: absolute; bottom: 1rem; right: 1rem; z-index: 5;
    width: 44px; height: 44px; background-color: var(--bg-secondary); color: var(--text-primary);
    border-radius: 50%; border: 1px solid var(--border-color); box-shadow: 0 4px 12px var(--shadow-color);
    cursor: pointer; display: flex; justify-content: center; align-items: center; transition: transform 0.2s, opacity 0.2s;
}
.scroll-btn-hidden { opacity: 0; transform: translateY(20px); pointer-events: none; }
.scroll-btn-visible { opacity: 1; transform: translateY(0); }
#new-message-count {
    position: absolute; top: -5px; right: -5px; background-color: var(--text-accent); color: white;
    min-width: 22px; height: 22px; padding: 2px; border-radius: 50%; font-size: 12px; font-weight: 600;
    display: none;
    justify-content: center; align-items: center; border: 2px solid var(--bg-secondary);
}

/* --- PATIČKA --- */
.footer-area { display: flex; flex-direction: column; background-color: var(--bg-secondary); border-top: 1px solid var(--border-color); flex-shrink: 0; position: relative; }
#typing-indicator { transition: opacity 0.3s; padding: 0.5rem 1rem; color: var(--text-secondary); font-style: italic; font-size: 0.85rem;}
.typing-indicator-hidden { opacity: 0; height: 0; padding: 0 1rem !important; }
.typing-indicator-visible { opacity: 1; display: flex; align-items: center; gap: 0.4rem; }
.typing-text { flex-shrink: 1; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
#image-preview-container { display: none; align-items: center; gap: 0.75rem; padding: 0.5rem 1rem; background-color: #f0f3f7; }
#image-preview { max-height: 3rem; border-radius: 4px; }
.preview-info { flex-grow: 1; overflow: hidden; font-size: 0.8rem; color: var(--text-secondary); }
#remove-image-btn { background:none; border:none; font-size: 1.5rem; color: #999; cursor:pointer; }
.typing-dot { width: 8px; height: 8px; border-radius: 50%; background-color: #d4d4d8; animation: typing-bounce 1.2s infinite ease-in-out; }
.typing-dot:nth-child(2) { animation-delay: -0.2s; }
.typing-dot:nth-child(3) { animation-delay: -0.4s; }
@keyframes typing-bounce { 0%, 80%, 100% { transform: scale(0); } 40% { transform: scale(1.0); } }
#app-footer { padding: 0.75rem 1rem; }
#chat-form { display: flex; align-items: flex-end; gap: 0.5rem; }
#message-input { 
    flex-grow: 1; 
    background-color: var(--bg-main); 
    border: 1px solid var(--border-color); 
    border-radius: 18px; 
    padding: 0.5rem 1rem; 
    color: var(--text-primary); 
    font-size: 1rem; 
    transition: border-color 0.2s, box-shadow 0.2s;
    resize: none;
    overflow-y: hidden;
    line-height: 1.5;
    max-height: 5em; /* Limit výšky */
}
#message-input:focus { outline: none; border-color: var(--text-accent); box-shadow: 0 0 0 3px rgba(0, 122, 255, 0.2); }
#send-button, .file-label, #emoji-picker-btn { flex-shrink: 0; display: flex; align-items: center; justify-content: center; width: 2.5rem; height: 2.5rem; border-radius: 50%; cursor: pointer; color: var(--text-secondary); transition: background-color 0.2s; background: none; border: none; font-size: 1.2rem; }
.file-label:hover, #emoji-picker-btn:hover { background-color: var(--border-color); }
#send-button { background-color: var(--text-accent); color: white; font-size: 1rem;}
#image-input { display: none; }

#emoji-picker {
    position: absolute;
    bottom: 100%;
    right: 1rem;
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: 12px;
    box-shadow: 0 4px 12px var(--shadow-color);
    padding: 0.5rem;
    display: grid;
    grid-template-columns: repeat(5, 1fr);
    gap: 0.25rem;
    width: 240px;
}
#emoji-picker button {
    background: none;
    border: none;
    font-size: 1.5rem;
    padding: 0.4rem;
    border-radius: 8px;
    cursor: pointer;
    transition: background-color .2s;
}
#emoji-picker button:hover {
    background-color: var(--bg-main);
}


/* --- MODÁLNÍ OKNA --- */
.modal-hidden, .modal-visible { position: fixed; left: 0; top: 0; width: 100%; height: 100dvh; display: flex; justify-content: center; align-items: center; transition: opacity 0.3s ease, visibility 0.3s; padding: 1rem; }
.modal-hidden { opacity: 0; visibility: hidden; }
.modal-visible { opacity: 1; visibility: visible; }
#welcome-modal, #image-modal, #gallery-modal, #info-modal, #user-profile-modal { background-color: rgba(0,0,0,0.6); backdrop-filter: blur(5px); }
#welcome-modal { z-index: 5000; }
#image-modal { z-index: 3000; flex-direction: column; justify-content: center; }
#gallery-modal { z-index: 2000; }
#info-modal { z-index: 6000; }
#user-profile-modal { z-index: 4000; }
.modal-content { max-width: 90vw; max-height: 80vh; animation: zoomIn 0.3s ease; }
.modal-close-btn { position: absolute; top: 15px; right: 35px; color: #f1f1f1; font-size: 40px; font-weight: bold; cursor: pointer; }
.welcome-modal-content, .info-modal-content { background: var(--bg-secondary); width: 90%; max-width: 500px; border-radius: 12px; display: flex; flex-direction: column; animation: zoomIn 0.3s ease; }
.gallery-modal-content, .user-profile-content {
    background: var(--bg-secondary);
    width: 95%;
    max-width: 600px;
    height: 95dvh;
    max-height: 800px;
    border-radius: 12px;
    display: grid;
    grid-template-rows: auto 1fr;
    animation: zoomIn 0.3s ease;
    overflow: hidden;
}
.gallery-header, .info-header, .user-profile-header { display: flex; justify-content: space-between; align-items: center; padding: 0.75rem 1.5rem; border-bottom: 1px solid var(--border-color); }
.gallery-header h2, .info-header h2, .user-profile-header h2 { font-size: 1rem; font-weight: 600; color: var(--text-primary); }
#gallery-close-btn, #info-close-btn, #user-profile-close-btn { background: none; border: none; font-size: 1.5rem; color: var(--text-secondary); cursor: pointer; }
.gallery-item { display: block; aspect-ratio: 1 / 1; background-color: var(--border-color); border-radius: 8px; overflow: hidden; transition: transform 0.2s; }
.gallery-item:hover { transform: scale(1.05); z-index: 5; }
.gallery-item img { width: 100%; height: 100%; object-fit: cover; }
@keyframes zoomIn { from { transform: scale(0.9); opacity: 0; } to { transform: scale(1); opacity: 1; } }
.welcome-modal-content { padding: 1.5rem; text-align: center; gap: 1rem; }
.welcome-modal-content h2 { font-size: 1.25rem; font-weight: 600; color: var(--text-primary); }
.welcome-modal-content p { color: var(--text-secondary); line-height: 1.5; }
#welcome-form { display: flex; flex-direction: column; gap: 1rem; }
#nickname-input { border: 1px solid var(--border-color); padding: 0.75rem; border-radius: 8px; font-size: 1rem; text-align: center; color: var(--text-primary); background-color: var(--bg-main); }
#nickname-input:focus { outline: none; border-color: var(--text-accent); box-shadow: 0 0 0 3px rgba(0, 122, 255, 0.2); }
#welcome-form button { background-color: var(--text-accent); color: white; border: none; padding: 0.75rem; border-radius: 8px; font-size: 1rem; font-weight: 500; cursor: pointer; }
.info-body { padding: 1.5rem; line-height: 1.6; color: var(--text-secondary); }
.info-body p:last-of-type { margin-top: 1rem; font-weight: 600; color: var(--text-primary); }

#modal-caption {
    color: white;
    text-align: center;
    padding: 10px 20px;
    max-width: 80vw;
    margin-top: 15px;
}
#modal-caption.hidden {
    display: none;
}
#modal-text {
    line-height: 1.5;
    margin-bottom: 10px;
}
#modal-text.hidden {
    display: none;
}
.modal-chat-link {
    display: inline-block;
    background-color: rgba(255, 255, 255, 0.2);
    color: white;
    padding: 8px 16px;
    border-radius: 20px;
    text-decoration: none;
    font-weight: 500;
    transition: background-color 0.2s;
}
.modal-chat-link:hover {
    background-color: rgba(255, 255, 255, 0.4);
}

/* --- ODPOVĚDI A REAKCE --- */
.message-info-wrapper { display: flex; justify-content: flex-end; align-items: flex-end; margin-top: 0.25rem; }
.message-actions { display: flex; gap: 0.25rem; margin-left: 0.5rem; opacity: 0; transition: opacity .2s; }
.message-bubble:hover .message-actions { opacity: 1; }
.reply-quote { 
    background-color: rgba(0,0,0,0.05); padding: 0.5rem; margin-bottom: 0.5rem; 
    border-left: 3px solid rgba(0,0,0,0.2); border-radius: 4px; font-size: 0.85rem; 
    opacity: 0.8; cursor: pointer; text-decoration: none; color: inherit;
    display: block; transition: background-color 0.2s ease;
}
.reply-quote:hover { background-color: rgba(0,0,0,0.1); }
.current-user .reply-quote { background-color: rgba(255,255,255,0.15); border-left-color: rgba(255,255,255,0.4); }
.current-user .reply-quote:hover { background-color: rgba(255,255,255,0.25); }
@keyframes highlight-blink {
  50% {
    box-shadow: 0 0 10px 4px var(--message-highlight-glow);
  }
}
.message-bubble.message-highlight {
    animation: highlight-blink 0.5s 10;
}

.reply-quote strong { font-weight: 600; }
.reply-quote p { white-space: normal; overflow: visible; text-overflow: unset; }
#reply-preview { display: none; justify-content: space-between; align-items: center; padding: 0.5rem 1rem; background-color: #eef2ff; border-top: 1px solid var(--border-color); font-size: 0.8rem; color: #4338ca; }
#reply-preview.visible { display: flex; }
#cancel-reply-btn { background: none; border: none; font-size: 1.5rem; cursor: pointer; }

.reaction-btn, .reply-btn { background: rgba(0,0,0,0.05); border: none; border-radius: 50%; width: 28px; height: 28px; cursor: pointer; display: flex; justify-content: center; align-items: center; color: inherit; transition: background-color .2s; font-size: 14px; }
.reaction-btn:hover, .reply-btn:hover { background: rgba(0,0,0,0.1); }
#reaction-popover { position: fixed; background: var(--bg-secondary); border-radius: 2rem; box-shadow: 0 4px 12px var(--shadow-color); padding: 0.25rem; display: flex; gap: 0.25rem; opacity: 0; pointer-events: none; transition: opacity 0.2s, transform 0.2s; z-index: 10; transform: translateY(10px); }
#reaction-popover.visible { opacity: 1; transform: translateY(0); pointer-events: auto; }
.reaction-popover-emoji { font-size: 1.5rem; padding: 0.25rem; border-radius: 50%; cursor: pointer; transition: transform 0.1s; }
.reaction-popover-emoji:hover { transform: scale(1.2); }

.message-footer-container { display: flex; flex-wrap: wrap; gap: 0.5rem; margin-top: 0.5rem; clear: both; align-items: center; }
.reactions-display { display: flex; flex-wrap: wrap; gap: 0.25rem; }
.reaction-chip { background: rgba(0,0,0,0.08); border: 1px solid transparent; border-radius: 1rem; padding: 0.25rem 0.6rem; font-size: 0.8rem; cursor: pointer; display: flex; align-items: center; }
.reaction-chip.reacted { background: #cfe5ff; color: var(--text-accent); border-color: var(--text-accent); }
.reaction-chip .count { font-weight: 600; margin-left: 0.25rem; font-size: 0.75rem; }

.reply-links-container { display: flex; align-items: center; gap: 0.5rem; font-size: 0.8rem; }
.reply-jumplink {
    background-color: #eef2ff;
    color: #4338ca;
    text-decoration: none;
    border-radius: 4px;
    padding: 0.1rem 0.4rem;
    font-weight: 500;
    transition: background-color .2s;
    cursor: pointer;
}
.reply-jumplink:hover {
    background-color: #dbeafe;
}


/* === GALERIE === */
.gallery-zoom-slider {
    width: 100px;
    margin: 0 1rem;
}
#gallery-grid-desktop, #gallery-grid-mobile {
    padding: 1rem;
    display: grid;
    grid-template-columns: repeat(auto-fill, var(--gallery-item-size, 90px));
    gap: 1rem;
    overflow-y: auto;
    flex-grow: 1;
    min-height: 0;
    align-content: start;
    justify-content: center;
}

#user-profile-messages {
    overflow-y: auto;
    padding: 1rem;
    display: flex;
    flex-direction: column;
    gap: 0.75rem;
    background-color: var(--bg-main);
    min-height: 0;
}

#gallery-grid-desktop .spinner, #gallery-grid-mobile .spinner,
#gallery-grid-desktop .empty-gallery-msg, #gallery-grid-mobile .empty-gallery-msg,
#user-profile-messages .spinner, #user-profile-messages .empty-chat-msg {
    grid-column: 1 / -1;
    align-self: center;
    justify-self: center;
    margin-top: 2rem;
}