/* Reset and Base Styles */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    --primary-bg: #1a1a2e;
    --secondary-bg: #16213e;
    --tertiary-bg: #0f3460;
    --accent-color: #e94560;
    --text-primary: #ffffff;
    --text-secondary: #a0a0a0;
    --border-color: #2a2a3e;
    --success-color: #4caf50;
    --warning-color: #ff9800;
    --max-width: 900px;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    background: var(--primary-bg);
    color: var(--text-primary);
    line-height: 1.6;
    overflow: hidden;
}

/* App Container */
#app {
    display: flex;
    flex-direction: column;
    height: 100vh;
    max-width: var(--max-width);
    margin: 0 auto;
}

/* Header */
.app-header {
    background: var(--secondary-bg);
    border-bottom: 2px solid var(--accent-color);
    padding: 1rem;
    text-align: center;
    flex-shrink: 0;
}

.app-title {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--accent-color);
    margin: 0;
}

.header-subtitle {
    font-size: 0.75rem;
    color: var(--text-secondary);
    margin-top: 0.25rem;
    text-transform: uppercase;
    letter-spacing: 1px;
}

/* Chat Container */
.chat-container {
    flex: 1;
    overflow-y: auto;
    padding: 1rem;
    display: flex;
    flex-direction: column;
    gap: 1rem;
}

/* Custom Scrollbar */
.chat-container::-webkit-scrollbar {
    width: 8px;
}

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

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

.chat-container::-webkit-scrollbar-thumb:hover {
    background: var(--accent-color);
}

/* Welcome Message */
.welcome-message {
    text-align: center;
    padding: 2rem 1rem;
    color: var(--text-secondary);
}

.welcome-message h2 {
    color: var(--accent-color);
    margin-bottom: 0.5rem;
}

.welcome-message p {
    margin: 0.5rem 0;
}

.help-text {
    font-size: 0.85rem;
    line-height: 1.8;
    margin-top: 1.5rem !important;
    padding: 1rem;
    background: var(--secondary-bg);
    border-radius: 8px;
    border-left: 3px solid var(--accent-color);
}

/* Chat Messages */
.message {
    display: flex;
    gap: 0.75rem;
    max-width: 85%;
    animation: fadeIn 0.3s ease-in;
}

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

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

.message.assistant {
    align-self: flex-start;
}

.message-avatar {
    width: 36px;
    height: 36px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.2rem;
    flex-shrink: 0;
}

.message.user .message-avatar {
    background: var(--accent-color);
}

.message.assistant .message-avatar {
    background: var(--tertiary-bg);
}

.message-content {
    background: var(--secondary-bg);
    padding: 0.75rem 1rem;
    border-radius: 12px;
    word-wrap: break-word;
    overflow-wrap: break-word;
}

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

.message.assistant .message-content {
    border-bottom-left-radius: 4px;
}

.message-text {
    white-space: pre-wrap;
}

.message-file-info {
    font-size: 0.85rem;
    color: var(--text-secondary);
    margin-top: 0.5rem;
    padding-top: 0.5rem;
    border-top: 1px solid rgba(255, 255, 255, 0.1);
}

.message-timestamp {
    font-size: 0.7rem;
    color: var(--text-secondary);
    margin-top: 0.25rem;
}

/* Input Area */
.input-area {
    background: var(--secondary-bg);
    border-top: 1px solid var(--border-color);
    padding: 1rem;
    flex-shrink: 0;
}

.file-preview {
    background: var(--tertiary-bg);
    padding: 0.5rem 1rem;
    border-radius: 8px;
    margin-bottom: 0.5rem;
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.file-preview.hidden {
    display: none;
}

.file-info {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    flex: 1;
}

.file-info span {
    font-size: 0.9rem;
    color: var(--text-primary);
}

.chat-form {
    display: flex;
    gap: 0.5rem;
    align-items: flex-end;
}

.btn-icon {
    background: var(--tertiary-bg);
    border: none;
    color: var(--text-primary);
    font-size: 1.25rem;
    width: 42px;
    height: 42px;
    border-radius: 8px;
    cursor: pointer;
    transition: all 0.2s ease;
    display: flex;
    align-items: center;
    justify-content: center;
}

.btn-icon:hover {
    background: var(--accent-color);
    transform: scale(1.05);
}

.btn-icon:active {
    transform: scale(0.95);
}

.message-input {
    flex: 1;
    background: var(--tertiary-bg);
    border: 1px solid var(--border-color);
    color: var(--text-primary);
    padding: 0.75rem 1rem;
    border-radius: 8px;
    font-size: 1rem;
    font-family: inherit;
    resize: none;
    max-height: 120px;
    overflow-y: auto;
    transition: border-color 0.2s ease;
}

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

.message-input::placeholder {
    color: var(--text-secondary);
}

.btn-send {
    background: var(--accent-color);
    border: none;
    color: var(--text-primary);
    width: 42px;
    height: 42px;
    border-radius: 8px;
    cursor: pointer;
    transition: all 0.2s ease;
    display: flex;
    align-items: center;
    justify-content: center;
}

.btn-send:hover {
    background: #ff5577;
    transform: scale(1.05);
}

.btn-send:active {
    transform: scale(0.95);
}

.btn-send:disabled {
    background: var(--tertiary-bg);
    cursor: not-allowed;
    transform: none;
}

.send-icon {
    font-size: 1.25rem;
}

/* Status Indicator */
.status-indicator {
    margin-top: 0.5rem;
    padding: 0.5rem 1rem;
    background: var(--tertiary-bg);
    border-radius: 8px;
    text-align: center;
    font-size: 0.85rem;
    color: var(--text-secondary);
}

.status-indicator.hidden {
    display: none;
}

.status-text::before {
    content: '';
    display: inline-block;
    width: 8px;
    height: 8px;
    background: var(--accent-color);
    border-radius: 50%;
    margin-right: 0.5rem;
    animation: pulse 1.5s ease-in-out infinite;
}

@keyframes pulse {
    0%, 100% {
        opacity: 1;
    }
    50% {
        opacity: 0.3;
    }
}

/* Error State */
.message.error .message-content {
    background: #5a1a1a;
    border-left: 3px solid var(--warning-color);
}

/* Loading Animation */
.loading-dots {
    display: inline-flex;
    gap: 4px;
}

.loading-dots span {
    width: 6px;
    height: 6px;
    background: var(--text-secondary);
    border-radius: 50%;
    animation: bounce 1.4s infinite ease-in-out;
}

.loading-dots span:nth-child(1) {
    animation-delay: -0.32s;
}

.loading-dots span:nth-child(2) {
    animation-delay: -0.16s;
}

@keyframes bounce {
    0%, 80%, 100% {
        transform: scale(0);
    }
    40% {
        transform: scale(1);
    }
}

/* Responsive Design */
@media (max-width: 600px) {
    .app-header {
        padding: 0.75rem;
    }

    .app-title {
        font-size: 1.25rem;
    }

    .header-subtitle {
        font-size: 0.65rem;
    }

    .chat-container {
        padding: 0.75rem;
    }

    .message {
        max-width: 90%;
    }

    .input-area {
        padding: 0.75rem;
    }

    .welcome-message {
        padding: 1.5rem 0.5rem;
    }

    .help-text {
        font-size: 0.8rem;
    }
}

/* PWA Install Prompt */
.install-prompt {
    position: fixed;
    bottom: 80px;
    left: 50%;
    transform: translateX(-50%);
    background: var(--secondary-bg);
    padding: 1rem 1.5rem;
    border-radius: 12px;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.3);
    border: 1px solid var(--accent-color);
    display: flex;
    gap: 1rem;
    align-items: center;
    max-width: 90%;
    z-index: 1000;
    animation: slideUp 0.3s ease;
}

@keyframes slideUp {
    from {
        transform: translateX(-50%) translateY(20px);
        opacity: 0;
    }
    to {
        transform: translateX(-50%) translateY(0);
        opacity: 1;
    }
}

.install-prompt button {
    background: var(--accent-color);
    border: none;
    color: var(--text-primary);
    padding: 0.5rem 1rem;
    border-radius: 6px;
    cursor: pointer;
    font-size: 0.9rem;
    font-weight: 600;
}

.install-prompt button:hover {
    background: #ff5577;
}