/* RESET & BASE */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    --bg-primary: #0f0f1e;
    --bg-secondary: #1a1a2e;
    --bg-tertiary: #252541;
    --bg-elevated: #2d2d4a;
    
    --accent: #7c3aed;
    --accent-light: #a78bfa;
    --accent-glow: rgba(124, 58, 237, 0.3);
    
    --text-primary: #f3f4f6;
    --text-secondary: #d1d5db;
    --text-tertiary: #9ca3af;
    
    --border: #374151;
    --success: #10b981;
    --error: #ef4444;
    
    --shadow: 0 4px 16px rgba(0, 0, 0, 0.4);
    --transition: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

body {
    font-family: 'Segoe UI', system-ui, sans-serif;
    background: var(--bg-primary);
    color: var(--text-primary);
    line-height: 1.6;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

#app {
    flex: 1;
    position: relative;
}

/* SCREEN TRANSITIONS */
.screen {
    display: none;
    opacity: 0;
    transform: translateY(20px);
    transition: opacity var(--transition), transform var(--transition);
}

.screen.active {
    display: block;
    animation: fadeInUp 0.4s forwards;
}

@keyframes fadeInUp {
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* LANDING PAGE */
.landing-container {
    max-width: 800px;
    margin: 0 auto;
    padding: 60px 20px;
    text-align: center;
}

.landing-logo {
    color: var(--accent);
    margin-bottom: 20px;
    animation: pulse 2s infinite;
}

@keyframes pulse {
    0%, 100% { opacity: 1; }
    50% { opacity: 0.7; }
}

.landing-title {
    font-size: 3rem;
    font-weight: 700;
    background: linear-gradient(135deg, var(--accent), var(--accent-light));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    margin-bottom: 10px;
}

.landing-subtitle {
    font-size: 1.2rem;
    color: var(--text-secondary);
    margin-bottom: 40px;
}

.landing-content {
    margin: 40px 0;
}

.info-section {
    background: var(--bg-secondary);
    border: 1px solid var(--border);
    border-radius: 12px;
    padding: 24px;
    margin-bottom: 20px;
    text-align: left;
}

.info-section h3 {
    color: var(--accent-light);
    margin-bottom: 10px;
}

.info-section p {
    color: var(--text-secondary);
}

.more-options {
    margin: 30px 0;
    background: var(--bg-tertiary);
    border-radius: 12px;
    overflow: hidden;
}

.more-options summary {
    padding: 16px 24px;
    cursor: pointer;
    font-weight: 600;
    color: var(--accent-light);
    list-style: none;
    transition: background var(--transition);
}

.more-options summary:hover {
    background: var(--bg-elevated);
}

.more-content {
    padding: 0 24px 24px;
    text-align: left;
}

.more-content h4 {
    color: var(--accent);
    margin: 16px 0 8px;
}

.more-content p {
    color: var(--text-secondary);
    margin-bottom: 12px;
}

/* BUTTONS */
.btn-primary {
    background: var(--accent);
    color: white;
    border: none;
    padding: 14px 32px;
    border-radius: 12px;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all var(--transition);
    box-shadow: 0 4px 12px var(--accent-glow);
    position: relative;
    overflow: hidden;
}

.btn-primary::before {
    content: '';
    position: absolute;
    top: 50%;
    left: 50%;
    width: 0;
    height: 0;
    border-radius: 50%;
    background: rgba(255, 255, 255, 0.2);
    transform: translate(-50%, -50%);
    transition: width 0.6s, height 0.6s;
}

.btn-primary:hover::before {
    width: 300px;
    height: 300px;
}

.btn-primary:hover {
    background: var(--accent-light);
    transform: translateY(-2px);
    box-shadow: 0 6px 20px var(--accent-glow);
}

.btn-primary:active {
    transform: translateY(0);
}

.btn-primary:disabled {
    opacity: 0.5;
    cursor: not-allowed;
    transform: none;
}

/* ACCESS SELECTION */
.access-container {
    max-width: 900px;
    margin: 60px auto;
    padding: 20px;
}

.screen-title {
    font-size: 2rem;
    text-align: center;
    margin-bottom: 40px;
    color: var(--accent-light);
}

.screen-subtitle {
    text-align: center;
    color: var(--text-secondary);
    margin-top: -30px;
    margin-bottom: 40px;
}

.access-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 30px;
}

.access-card {
    background: var(--bg-secondary);
    border: 2px solid var(--border);
    border-radius: 16px;
    padding: 30px;
    transition: all var(--transition);
}

.access-card:hover {
    border-color: var(--accent);
    box-shadow: var(--shadow);
}

.access-icon {
    font-size: 3rem;
    margin-bottom: 16px;
}

.access-card h3 {
    margin-bottom: 12px;
    color: var(--text-primary);
}

.access-card p {
    color: var(--text-secondary);
    margin-bottom: 20px;
}

.access-form input {
    width: 100%;
    padding: 12px;
    background: var(--bg-primary);
    border: 1px solid var(--border);
    border-radius: 8px;
    color: var(--text-primary);
    font-size: 1rem;
    margin-bottom: 12px;
}

.access-form input:focus {
    outline: none;
    border-color: var(--accent);
}

.help-text {
    font-size: 0.85rem;
    color: var(--text-tertiary);
    margin-bottom: 12px;
}

.help-text a {
    color: var(--accent-light);
    text-decoration: none;
}

.error-text {
    color: var(--error);
    font-size: 0.9rem;
    min-height: 20px;
    margin-bottom: 12px;
}

/* MODEL SELECTION */
.models-container {
    max-width: 1200px;
    margin: 60px auto;
    padding: 20px;
}

.models-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
    gap: 20px;
}

.model-card {
    background: var(--bg-secondary);
    border: 2px solid var(--border);
    border-radius: 16px;
    padding: 24px;
    cursor: pointer;
    transition: all var(--transition);
    position: relative;
    overflow: hidden;
}

.model-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: linear-gradient(90deg, transparent, rgba(124, 58, 237, 0.1), transparent);
    transition: left 0.5s;
}

.model-card:hover::before {
    left: 100%;
}

.model-card:hover {
    border-color: var(--accent);
    transform: translateY(-6px);
    box-shadow: 0 12px 24px rgba(0, 0, 0, 0.3);
}

.model-card.recommended {
    border-color: var(--accent);
    box-shadow: 0 0 20px var(--accent-glow);
}

.model-badge {
    position: absolute;
    top: 12px;
    right: 12px;
    background: var(--accent);
    color: white;
    padding: 4px 12px;
    border-radius: 12px;
    font-size: 0.75rem;
    font-weight: 600;
}

.model-icon {
    font-size: 2.5rem;
    margin-bottom: 12px;
}

.model-card h3 {
    margin-bottom: 8px;
}

.model-card p {
    color: var(--text-secondary);
    font-size: 0.9rem;
    margin-bottom: 16px;
}

.model-specs {
    display: flex;
    flex-direction: column;
    gap: 4px;
    font-size: 0.85rem;
    color: var(--text-tertiary);
    font-family: monospace;
}

/* CHARACTER SELECTION */
.characters-container {
    max-width: 1200px;
    margin: 60px auto;
    padding: 20px;
}

.characters-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 40px;
}

.settings-btn {
    background: var(--bg-secondary);
    border: 1px solid var(--border);
    color: var(--accent-light);
    padding: 12px;
    border-radius: 8px;
    cursor: pointer;
    transition: all var(--transition);
}

.settings-btn:hover {
    background: var(--bg-tertiary);
    transform: scale(1.05);
}

.settings-menu {
    display: none;
    background: var(--bg-secondary);
    border: 1px solid var(--border);
    border-radius: 12px;
    padding: 12px;
    margin-bottom: 30px;
}

.settings-menu.active {
    display: flex;
    gap: 12px;
    flex-wrap: wrap;
}

.settings-menu button {
    display: flex;
    align-items: center;
    gap: 8px;
    background: var(--bg-tertiary);
    border: 1px solid var(--border);
    color: var(--text-primary);
    padding: 10px 16px;
    border-radius: 8px;
    cursor: pointer;
    transition: all var(--transition);
}

.settings-menu button:hover {
    background: var(--bg-elevated);
    border-color: var(--accent);
}

.characters-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 24px;
}

.character-card {
    background: var(--bg-secondary);
    border: 2px solid var(--border);
    border-radius: 16px;
    padding: 24px;
    cursor: pointer;
    transition: all var(--transition);
    text-align: center;
    position: relative;
    overflow: hidden;
}

.character-card::after {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: radial-gradient(circle at center, var(--accent-glow), transparent);
    opacity: 0;
    transition: opacity var(--transition);
}

.character-card:hover::after {
    opacity: 1;
}

.character-card:hover {
    border-color: var(--accent);
    transform: translateY(-6px) scale(1.02);
    box-shadow: 0 12px 32px rgba(0, 0, 0, 0.4);
}

.character-img {
    width: 120px;
    height: 120px;
    border-radius: 50%;
    object-fit: cover;
    margin-bottom: 16px;
    border: 3px solid var(--accent);
    transition: all var(--transition);
    position: relative;
    z-index: 1;
}

.character-card:hover .character-img {
    transform: scale(1.1);
    box-shadow: 0 8px 24px var(--accent-glow);
}

.character-role {
    color: var(--accent-light);
    font-size: 0.9rem;
    margin: 8px 0;
}

.character-desc {
    color: var(--text-secondary);
    font-size: 0.9rem;
}

/* CHAT INTERFACE */
.chat-layout {
    height: 100vh;
    display: flex;
    flex-direction: column;
    background: var(--bg-primary);
}

/* Fixed Chat Header */
.chat-header {
    position: sticky;
    top: 0;
    background: var(--bg-secondary);
    border-bottom: 1px solid var(--border);
    padding: 16px 24px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    z-index: 100;
    backdrop-filter: blur(10px);
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
}

.chat-header-left {
    display: flex;
    align-items: center;
    gap: 12px;
}

.chat-avatar {
    width: 48px;
    height: 48px;
    border-radius: 50%;
    border: 2px solid var(--accent);
    object-fit: cover;
}

.chat-header-info h3 {
    margin: 0;
    font-size: 1.1rem;
    color: var(--text-primary);
}

.chat-status {
    display: flex;
    align-items: center;
    gap: 6px;
    color: var(--success);
    font-size: 0.85rem;
}

.status-dot {
    width: 8px;
    height: 8px;
    background: var(--success);
    border-radius: 50%;
    animation: pulse-dot 2s infinite;
}

@keyframes pulse-dot {
    0%, 100% { opacity: 1; }
    50% { opacity: 0.5; }
}

.chat-header-actions {
    display: flex;
    gap: 8px;
}

.icon-btn {
    background: var(--bg-tertiary);
    border: 1px solid var(--border);
    color: var(--text-secondary);
    width: 40px;
    height: 40px;
    border-radius: 8px;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all var(--transition);
}

.icon-btn:hover {
    background: var(--bg-elevated);
    color: var(--accent-light);
    border-color: var(--accent);
    transform: translateY(-2px);
}

/* Messages Container */
.chat-messages-container {
    flex: 1;
    overflow-y: auto;
    overflow-x: hidden;
    background: var(--bg-primary);
}

.chat-messages {
    max-width: 900px;
    margin: 0 auto;
    padding: 24px;
    min-height: 100%;
}

.message {
    display: flex;
    gap: 12px;
    margin-bottom: 24px;
    align-items: flex-start;
    opacity: 0;
    animation: slideIn 0.3s forwards;
}

@keyframes slideIn {
    from {
        opacity: 0;
        transform: translateY(10px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.message.user-message {
    flex-direction: row-reverse;
}

.message-avatar {
    width: 40px;
    height: 40px;
    border-radius: 50%;
    border: 2px solid var(--accent);
    flex-shrink: 0;
    object-fit: cover;
}

.message-bubble {
    max-width: 70%;
    display: flex;
    flex-direction: column;
}

.message-content {
    background: var(--bg-secondary);
    padding: 12px 16px;
    border-radius: 16px;
    color: var(--text-primary);
    line-height: 1.5;
    word-wrap: break-word;
}

.user-message .message-content {
    background: var(--accent);
    color: white;
    border-radius: 16px 16px 4px 16px;
}

.character-message .message-content {
    border-radius: 16px 16px 16px 4px;
}

.message-content em {
    font-style: italic;
    opacity: 0.9;
}

.message-content strong {
    font-weight: 600;
}

.message-time {
    font-size: 0.75rem;
    color: var(--text-tertiary);
    margin-top: 4px;
    padding: 0 8px;
}

.user-message .message-time {
    text-align: right;
}

/* Fixed Input Area */
.chat-input-container {
    position: sticky;
    bottom: 0;
    background: var(--bg-secondary);
    border-top: 1px solid var(--border);
    padding: 16px 24px;
    backdrop-filter: blur(10px);
    box-shadow: 0 -2px 8px rgba(0, 0, 0, 0.1);
}

.typing-indicator {
    display: none;
    align-items: center;
    gap: 8px;
    padding: 8px 0 12px;
    margin: 0 auto;
    max-width: 900px;
}

.typing-indicator.active {
    display: flex;
}

.typing-dots {
    display: flex;
    gap: 4px;
}

.typing-dots span {
    width: 8px;
    height: 8px;
    background: var(--accent);
    border-radius: 50%;
    animation: typing 1.4s infinite;
}

.typing-dots span:nth-child(2) {
    animation-delay: 0.2s;
}

.typing-dots span:nth-child(3) {
    animation-delay: 0.4s;
}

@keyframes typing {
    0%, 60%, 100% { 
        transform: translateY(0);
        opacity: 0.4;
    }
    30% { 
        transform: translateY(-10px);
        opacity: 1;
    }
}

.typing-text {
    color: var(--text-tertiary);
    font-size: 0.85rem;
}

.chat-input-wrapper {
    display: flex;
    gap: 12px;
    align-items: flex-end;
    max-width: 900px;
    margin: 0 auto;
}

#chat-input {
    flex: 1;
    background: var(--bg-tertiary);
    border: 2px solid var(--border);
    border-radius: 12px;
    padding: 12px 16px;
    color: var(--text-primary);
    font-size: 1rem;
    font-family: inherit;
    resize: none;
    max-height: 120px;
    transition: border-color var(--transition);
}

#chat-input:focus {
    outline: none;
    border-color: var(--accent);
    box-shadow: 0 0 0 3px var(--accent-glow);
}

#chat-input:disabled {
    opacity: 0.6;
    cursor: not-allowed;
}

.send-btn {
    background: var(--accent);
    border: none;
    color: white;
    width: 48px;
    height: 48px;
    border-radius: 12px;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all var(--transition);
    flex-shrink: 0;
}

.send-btn:hover:not(:disabled) {
    background: var(--accent-light);
    transform: translateY(-2px);
    box-shadow: 0 4px 12px var(--accent-glow);
}

.send-btn:disabled {
    opacity: 0.4;
    cursor: not-allowed;
    transform: none;
}

.send-btn svg {
    transition: transform var(--transition);
}

.send-btn:hover:not(:disabled) svg {
    transform: rotate(-15deg);
}

/* LOADING OVERLAY */
.loading-overlay {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(15, 15, 30, 0.95);
    backdrop-filter: blur(8px);
    z-index: 9999;
    justify-content: center;
    align-items: center;
    flex-direction: column;
    gap: 20px;
}

.loading-overlay.active {
    display: flex;
}

.spinner {
    width: 50px;
    height: 50px;
    border: 4px solid var(--border);
    border-top-color: var(--accent);
    border-radius: 50%;
    animation: spin 1s linear infinite;
}

@keyframes spin {
    to { transform: rotate(360deg); }
}

#loading-text {
    color: var(--text-secondary);
    font-size: 1.1rem;
}

/* FOOTER */
.app-footer {
    background: var(--bg-secondary);
    border-top: 1px solid var(--border);
    padding: 16px 20px;
    text-align: center;
    position: relative;
    z-index: 10;
}

/* Hide footer on chat screen */
#screen-chat.active ~ .app-footer {
    display: none;
}

.footer-content {
    max-width: 1200px;
    margin: 0 auto;
}

.footer-text {
    color: var(--text-tertiary);
    font-size: 0.9rem;
}

.footer-link {
    color: var(--accent-light);
    text-decoration: none;
    transition: color var(--transition);
    font-weight: 500;
}

.footer-link:hover {
    color: var(--accent);
    text-decoration: underline;
}

/* SCROLLBAR */
::-webkit-scrollbar {
    width: 8px;
}

::-webkit-scrollbar-track {
    background: var(--bg-primary);
}

::-webkit-scrollbar-thumb {
    background: var(--bg-tertiary);
    border-radius: 4px;
}

::-webkit-scrollbar-thumb:hover {
    background: var(--border);
}

/* RESPONSIVE */
@media (max-width: 768px) {
    .landing-title {
        font-size: 2rem;
    }
    
    .access-grid,
    .models-grid,
    .characters-grid {
        grid-template-columns: 1fr;
    }
    
    .chat-header {
        padding: 12px 16px;
    }
    
    .chat-avatar {
        width: 40px;
        height: 40px;
    }
    
    .chat-header-info h3 {
        font-size: 1rem;
    }
    
    .chat-messages {
        padding: 16px;
    }
    
    .message-bubble {
        max-width: 85%;
    }
    
    .message-avatar {
        width: 32px;
        height: 32px;
    }
    
    .chat-input-container {
        padding: 12px 16px;
    }
    
    #chat-input {
        font-size: 0.95rem;
    }
    
    .send-btn {
        width: 44px;
        height: 44px;
    }
    
    .icon-btn {
        width: 36px;
        height: 36px;
    }
    
    .scroll-to-bottom {
        bottom: 90px;
        right: 16px;
    }
}

/* ==========================================
   OFFLINE INDICATOR
   ========================================== */

.offline-indicator {
    position: fixed;
    top: -60px;
    left: 50%;
    transform: translateX(-50%);
    background: var(--error);
    color: white;
    padding: 12px 24px;
    border-radius: 0 0 12px 12px;
    display: flex;
    align-items: center;
    gap: 8px;
    z-index: 9999;
    transition: top var(--transition);
    box-shadow: var(--shadow);
}

.offline-indicator.visible {
    top: 0;
}

/* ==========================================
   SCROLL TO BOTTOM BUTTON
   ========================================== */

.scroll-to-bottom {
    position: fixed;
    bottom: 120px;
    right: 24px;
    width: 48px;
    height: 48px;
    background: var(--accent);
    border: none;
    border-radius: 50%;
    color: white;
    cursor: pointer;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.3);
    display: flex;
    align-items: center;
    justify-content: center;
    opacity: 0;
    visibility: hidden;
    transform: translateY(20px);
    transition: all var(--transition);
    z-index: 50;
}

.scroll-to-bottom.visible {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
}

.scroll-to-bottom:hover {
    background: var(--accent-light);
    transform: translateY(-2px);
}

/* ==========================================
   COPY BUTTON IN MESSAGES
   ========================================== */

.message-footer {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-top: 4px;
    gap: 8px;
}

.copy-btn {
    background: transparent;
    border: 1px solid transparent;
    color: var(--text-tertiary);
    padding: 4px;
    border-radius: 4px;
    cursor: pointer;
    opacity: 0;
    transition: all var(--transition);
    display: flex;
    align-items: center;
    justify-content: center;
}

.message-bubble:hover .copy-btn {
    opacity: 1;
}

.copy-btn:hover {
    background: var(--bg-tertiary);
    border-color: var(--border);
    color: var(--accent-light);
}

.copy-btn svg {
    width: 16px;
    height: 16px;
}

/* ==========================================
   ERROR TOAST
   ========================================== */

.error-toast {
    position: fixed;
    bottom: 24px;
    left: 50%;
    transform: translateX(-50%) translateY(100px);
    background: var(--bg-elevated);
    border: 1px solid var(--border);
    color: var(--text-primary);
    padding: 16px 24px;
    border-radius: 12px;
    box-shadow: var(--shadow);
    z-index: 10000;
    max-width: 90%;
    opacity: 0;
    transition: all var(--transition);
}

.error-toast.visible {
    opacity: 1;
    transform: translateX(-50%) translateY(0);
}

/* ==========================================
   LIGHT THEME
   ========================================== */

[data-theme="light"] {
    --bg-primary: #f5f7fa;
    --bg-secondary: #ffffff;
    --bg-tertiary: #e8edf5;
    --bg-elevated: #f0f4f8;
    
    --text-primary: #1a1a2e;
    --text-secondary: #3d3d5c;
    --text-tertiary: #6b6b8a;
    
    --border: #d1d5e0;
}

[data-theme="light"] .message-content {
    background: var(--bg-tertiary);
    color: var(--text-primary);
}

[data-theme="light"] .user-message .message-content {
    background: var(--accent);
    color: white;
}

[data-theme="light"] .loading-overlay {
    background: rgba(245, 247, 250, 0.95);
}

[data-theme="light"] .offline-indicator {
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.15);
}