/* ========================================
   PhaaS - Philosophy as a Service
   Modern AI Chat Interface with Thinking Tree
   ======================================== */

:root {
    /* Dark Theme Colors */
    --bg-primary: #0f0f1e;
    --bg-secondary: #1a1a2e;
    --bg-tertiary: #252541;
    --bg-hover: #2d2d4a;
    --text-primary: #e4e4e7;
    --text-secondary: #a1a1aa;
    --text-tertiary: #71717a;
    --accent-primary: #818cf8;
    --accent-secondary: #6366f1;
    --accent-gradient: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    --border-color: #27273f;
    --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.3);
    --shadow-md: 0 4px 6px rgba(0, 0, 0, 0.4);
    --shadow-lg: 0 10px 15px rgba(0, 0, 0, 0.5);
    
    /* Thinking Tree Colors */
    --thinking-bg: rgba(129, 140, 248, 0.1);
    --thinking-border: rgba(129, 140, 248, 0.3);
    --thinking-text: #c7d2fe;
    
    /* Spacing */
    --spacing-xs: 0.25rem;
    --spacing-sm: 0.5rem;
    --spacing-md: 1rem;
    --spacing-lg: 1.5rem;
    --spacing-xl: 2rem;
    
    /* Typography */
    --font-primary: 'Inter', 'Noto Sans KR', -apple-system, BlinkMacSystemFont, sans-serif;
    --font-mono: 'Fira Code', 'Courier New', monospace;
}

/* ========================================
   Global Styles
   ======================================== */

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: var(--font-primary);
    background: var(--bg-primary);
    color: var(--text-primary);
    line-height: 1.6;
    overflow-x: hidden;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

/* ========================================
   App Container
   ======================================== */

.app-container {
    display: flex;
    flex-direction: column;
    height: 100vh;
    width: 100vw;
    overflow: hidden;
}

/* ========================================
   Header
   ======================================== */

.app-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: var(--spacing-md) var(--spacing-lg);
    background: var(--bg-secondary);
    border-bottom: 1px solid var(--border-color);
    box-shadow: var(--shadow-sm);
    z-index: 100;
}

.header-left,
.header-right {
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
}

.app-title {
    font-size: 1.5rem;
    font-weight: 700;
    background: var(--accent-gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.icon-btn {
    width: 2.5rem;
    height: 2.5rem;
    border: none;
    background: transparent;
    color: var(--text-secondary);
    border-radius: 0.5rem;
    cursor: pointer;
    transition: all 0.2s ease;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.1rem;
}

.icon-btn:hover {
    background: var(--bg-tertiary);
    color: var(--text-primary);
}

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

/* ========================================
   Sidebar
   ======================================== */

.sidebar {
    position: fixed;
    left: -300px;
    top: 4rem;
    width: 300px;
    height: calc(100vh - 4rem);
    background: var(--bg-secondary);
    border-right: 1px solid var(--border-color);
    transition: left 0.3s ease;
    z-index: 90;
    overflow-y: auto;
    display: flex;
    flex-direction: column;
}

.sidebar.active {
    left: 0;
}

.sidebar-menu {
    padding: var(--spacing-lg);
    padding-bottom: 0;
    display: flex;
    flex-direction: column;
    gap: var(--spacing-sm);
}

.menu-btn {
    width: 100%;
    padding: var(--spacing-md);
    background: var(--bg-tertiary);
    color: var(--text-primary);
    border: 1px solid var(--border-color);
    border-radius: 0.5rem;
    cursor: pointer;
    font-weight: 500;
    font-size: 0.9rem;
    transition: all 0.2s ease;
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
}

.menu-btn:hover {
    background: var(--bg-hover);
    border-color: var(--accent-primary);
    transform: translateX(4px);
}

.menu-btn i {
    color: var(--accent-primary);
}

.sidebar-header {
    padding: var(--spacing-lg);
    border-bottom: 1px solid var(--border-color);
}

.sidebar-header h2 {
    font-size: 1.1rem;
    font-weight: 600;
    margin-bottom: var(--spacing-md);
    color: var(--text-primary);
}

.btn-new-chat {
    width: 100%;
    padding: var(--spacing-md);
    background: var(--accent-gradient);
    color: white;
    border: none;
    border-radius: 0.5rem;
    cursor: pointer;
    font-weight: 500;
    transition: all 0.2s ease;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-sm);
}

.btn-new-chat:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
}

.chat-history {
    flex: 1;
    padding: var(--spacing-md);
}

.chat-history-item {
    padding: var(--spacing-md);
    margin-bottom: var(--spacing-sm);
    background: var(--bg-tertiary);
    border-radius: 0.5rem;
    cursor: pointer;
    transition: all 0.2s ease;
    border: 1px solid transparent;
}

.chat-history-item:hover {
    background: var(--bg-hover);
    border-color: var(--accent-primary);
}

.chat-history-item.active {
    background: var(--bg-hover);
    border-color: var(--accent-primary);
}

.chat-history-item h4 {
    font-size: 0.9rem;
    font-weight: 500;
    margin-bottom: var(--spacing-xs);
    color: var(--text-primary);
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
}

.chat-history-item p {
    font-size: 0.8rem;
    color: var(--text-tertiary);
}

/* ========================================
   Main Content
   ======================================== */

.main-content {
    flex: 1;
    display: flex;
    flex-direction: column;
    position: relative;
    overflow: auto;
    padding-bottom: 180px;
}

/* ========================================
   Welcome Screen
   ======================================== */

.welcome-screen {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: flex-start;
    padding: var(--spacing-xl);
    padding-top: calc(var(--spacing-xl) * 2);
    padding-bottom: var(--spacing-lg);
    max-width: 900px;
    margin: 0 auto;
    text-align: center;
    overflow-y: auto;
}

.welcome-logo {
    margin-bottom: var(--spacing-md);
    animation: float 3s ease-in-out infinite;
}

.welcome-logo-img {
    width: 150px;
    height: 150px;
    object-fit: contain;
    filter: drop-shadow(0 4px 12px rgba(129, 140, 248, 0.3));
}

.welcome-logo i {
    background: var(--accent-gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

@keyframes float {
    0%, 100% { transform: translateY(0); }
    50% { transform: translateY(-10px); }
}

.welcome-title {
    font-size: 2rem;
    font-weight: 700;
    margin-bottom: var(--spacing-sm);
    color: var(--text-primary);
}

.welcome-subtitle {
    font-size: 1.1rem;
    color: var(--text-secondary);
    margin-bottom: var(--spacing-lg);
}

.welcome-examples {
    width: 100%;
}

.welcome-examples h3 {
    font-size: 1.2rem;
    font-weight: 600;
    margin-bottom: var(--spacing-lg);
    color: var(--text-primary);
}

.example-cards {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: var(--spacing-md);
}

.example-card {
    padding: var(--spacing-lg);
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: 0.75rem;
    cursor: pointer;
    transition: all 0.3s ease;
    text-align: left;
}

.example-card:hover {
    background: var(--bg-tertiary);
    border-color: var(--accent-primary);
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
}

.example-card i {
    font-size: 1.5rem;
    color: var(--accent-primary);
    margin-bottom: var(--spacing-md);
    display: block;
}

.example-card p {
    font-size: 0.9rem;
    color: var(--text-secondary);
    line-height: 1.5;
}

/* ========================================
   Chat Container
   ======================================== */

.chat-container {
    flex: 1;
    display: flex;
    flex-direction: column;
    overflow: hidden;
}

.messages-wrapper {
    flex: 1;
    overflow-y: auto;
    padding: var(--spacing-xl);
    scroll-behavior: smooth;
}

.message {
    margin-bottom: var(--spacing-lg);
    animation: fadeIn 0.3s ease;
}

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

.message-user {
    display: flex;
    justify-content: flex-end;
}

.message-assistant {
    display: flex;
    justify-content: flex-start;
}

.message-content {
    max-width: 70%;
    padding: var(--spacing-lg);
    border-radius: 1rem;
    line-height: 1.7;
}

.message-user .message-content {
    background: var(--accent-gradient);
    color: white;
    border-bottom-right-radius: 0.25rem;
}

.message-assistant .message-content {
    background: var(--bg-secondary);
    color: var(--text-primary);
    border-bottom-left-radius: 0.25rem;
    border: 1px solid var(--border-color);
}

/* AI 응답 메시지 내부 포맷팅 */
.message-assistant .message-content h3 {
    color: var(--accent-primary);
    font-size: 1.1rem;
    font-weight: 600;
    margin-top: calc(var(--spacing-xl) * 1.5);
    margin-bottom: var(--spacing-md);
    line-height: 1.4;
}

.message-assistant .message-content h3:first-child {
    margin-top: 0;
}

.message-assistant .message-content h4 {
    color: var(--text-primary);
    font-size: 1rem;
    font-weight: 600;
    margin-top: var(--spacing-lg);
    margin-bottom: var(--spacing-sm);
    line-height: 1.4;
}

.message-assistant .message-content p {
    margin-bottom: var(--spacing-sm);
    line-height: 1.6;
}

.message-assistant .message-content p + p {
    margin-top: var(--spacing-sm);
}

.message-assistant .message-content p:last-child {
    margin-bottom: 0;
}

.message-assistant .message-content h3 + p,
.message-assistant .message-content h4 + p {
    margin-top: 0;
}

.message-assistant .message-content ul,
.message-assistant .message-content ol {
    margin: var(--spacing-md) 0;
    padding-left: var(--spacing-xl);
    line-height: 1.6;
}

.message-assistant .message-content li {
    margin-bottom: var(--spacing-xs);
}

.message-assistant .message-content li:last-child {
    margin-bottom: 0;
}

.message-assistant .message-content blockquote {
    border-left: 4px solid var(--accent-primary);
    margin: var(--spacing-xl) 0;
    font-style: italic;
    color: var(--text-secondary);
    background: var(--bg-tertiary);
    padding: var(--spacing-md) var(--spacing-lg);
    border-radius: 0.5rem;
    line-height: 1.6;
}

.message-assistant .message-content blockquote strong {
    color: var(--accent-primary);
    font-style: normal;
}

.message-assistant .message-content blockquote p {
    margin-bottom: var(--spacing-xs);
}

.message-assistant .message-content strong {
    color: var(--accent-primary);
    font-weight: 600;
}

.message-assistant .message-content em {
    color: var(--text-tertiary);
}

.message-assistant .message-content hr {
    border: none;
    border-top: 1px solid var(--border-color);
    margin: calc(var(--spacing-xl) * 1.5) 0;
}

/* ========================================
   Thinking Tree
   ======================================== */

.thinking-tree {
    background: var(--thinking-bg);
    border: 1px solid var(--thinking-border);
    border-radius: 0.75rem;
    padding: var(--spacing-lg);
    margin-bottom: var(--spacing-md);
    max-width: 70%;
}

.thinking-header {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    margin-bottom: var(--spacing-md);
    color: var(--accent-primary);
    font-weight: 600;
}

.thinking-header i {
    animation: pulse 2s ease-in-out infinite;
}

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

.thinking-content {
    font-size: 0.9rem;
    color: var(--thinking-text);
}

.thinking-step {
    padding: var(--spacing-sm) 0;
    padding-left: var(--spacing-lg);
    border-left: 2px solid var(--thinking-border);
    margin-bottom: var(--spacing-sm);
    position: relative;
}

.thinking-step::before {
    content: '';
    position: absolute;
    left: -5px;
    top: 50%;
    transform: translateY(-50%);
    width: 8px;
    height: 8px;
    background: var(--accent-primary);
    border-radius: 50%;
}

.thinking-step-title {
    font-weight: 600;
    color: var(--accent-primary);
    margin-bottom: var(--spacing-xs);
}

.thinking-step-content {
    color: var(--thinking-text);
    line-height: 1.6;
}

/* ========================================
   Input Area
   ======================================== */

.input-area {
    position: fixed;
    bottom: 0;
    left: 0;
    right: 0;
    padding: var(--spacing-lg);
    background: var(--bg-secondary);
    border-top: 1px solid var(--border-color);
    z-index: 100;
}

.input-wrapper {
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
    background: var(--bg-tertiary);
    border-radius: 1.5rem;
    padding: var(--spacing-sm) var(--spacing-md);
    border: 2px solid var(--border-color);
    transition: border-color 0.2s ease;
    min-height: 3rem;
}

.input-wrapper:focus-within {
    border-color: var(--accent-primary);
}

.message-input {
    flex: 1;
    background: transparent;
    border: none;
    outline: none;
    color: var(--text-primary);
    font-family: var(--font-primary);
    font-size: 1rem;
    resize: none;
    max-height: 150px;
    padding: var(--spacing-sm);
    overflow-y: hidden;
    line-height: 1.5;
    vertical-align: middle;
}

.message-input:focus {
    overflow-y: auto;
}

/* 스크롤바 스타일링 */
.message-input::-webkit-scrollbar {
    width: 6px;
}

.message-input::-webkit-scrollbar-track {
    background: transparent;
}

.message-input::-webkit-scrollbar-thumb {
    background: var(--border-color);
    border-radius: 3px;
}

.message-input::-webkit-scrollbar-thumb:hover {
    background: var(--text-tertiary);
}

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

.send-button {
    width: 2.5rem;
    height: 2.5rem;
    border: none;
    background: var(--accent-gradient);
    color: white;
    border-radius: 50%;
    cursor: pointer;
    transition: all 0.2s ease;
    display: flex;
    align-items: center;
    justify-content: center;
    flex-shrink: 0;
}

.send-button:hover {
    transform: scale(1.1);
    box-shadow: var(--shadow-md);
}

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

.send-button:disabled {
    opacity: 0.5;
    cursor: not-allowed;
}

.input-hint {
    margin-top: var(--spacing-sm);
    font-size: 0.75rem;
    color: var(--text-tertiary);
    text-align: center;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-xs);
    flex-wrap: wrap;
}

.version-tag {
    margin-left: var(--spacing-xs);
    font-size: 0.65rem;
    opacity: 0.5;
    font-weight: 500;
}

/* ========================================
   Modal
   ======================================== */

.modal {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.8);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 1000;
    backdrop-filter: blur(5px);
}

.modal-content {
    background: var(--bg-secondary);
    border-radius: 1rem;
    width: 90%;
    max-width: 500px;
    border: 1px solid var(--border-color);
    box-shadow: var(--shadow-lg);
    animation: slideUp 0.3s ease;
}

.modal-large {
    max-width: 800px;
    max-height: 85vh;
    overflow-y: auto;
}

.philosophy-content {
    line-height: 1.8;
}

.philosophy-content h3 {
    color: var(--accent-primary);
    margin-bottom: var(--spacing-lg);
    text-align: center;
}

.philosophy-content h3 small {
    display: block;
    font-size: 0.8rem;
    margin-top: var(--spacing-xs);
    color: var(--text-secondary);
}

.philosophy-content h4 {
    color: var(--accent-primary);
    margin-top: var(--spacing-xl);
    margin-bottom: var(--spacing-md);
    font-size: 1.1rem;
}

.philosophy-content blockquote {
    border-left: 4px solid var(--accent-primary);
    padding-left: var(--spacing-lg);
    margin: var(--spacing-lg) 0;
    font-style: italic;
    color: var(--text-secondary);
}

.philosophy-content ul,
.philosophy-content ol {
    padding-left: var(--spacing-xl);
    margin: var(--spacing-md) 0;
}

.philosophy-content li {
    margin-bottom: var(--spacing-sm);
}

.philosophy-content ul ul {
    margin-top: var(--spacing-xs);
    font-size: 0.95rem;
}

.philosophy-content strong {
    color: var(--accent-primary);
}

.philosophy-content em {
    color: var(--text-tertiary);
}

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

.modal-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: var(--spacing-lg);
    border-bottom: 1px solid var(--border-color);
}

.modal-header h2 {
    font-size: 1.3rem;
    font-weight: 600;
    color: var(--text-primary);
}

.modal-close {
    width: 2rem;
    height: 2rem;
    border: none;
    background: transparent;
    color: var(--text-secondary);
    cursor: pointer;
    border-radius: 0.25rem;
    transition: all 0.2s ease;
}

.modal-close:hover {
    background: var(--bg-tertiary);
    color: var(--text-primary);
}

.modal-body {
    padding: var(--spacing-lg);
}

.setting-item {
    margin-bottom: var(--spacing-lg);
}

.setting-item label {
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
    cursor: pointer;
    color: var(--text-primary);
}

.setting-item input[type="checkbox"] {
    width: 1.2rem;
    height: 1.2rem;
    cursor: pointer;
}

.setting-item select {
    flex: 1;
    padding: var(--spacing-sm);
    background: var(--bg-tertiary);
    border: 1px solid var(--border-color);
    border-radius: 0.5rem;
    color: var(--text-primary);
    cursor: pointer;
}

.btn-danger {
    width: 100%;
    padding: var(--spacing-md);
    background: #dc2626;
    color: white;
    border: none;
    border-radius: 0.5rem;
    font-size: 0.95rem;
    font-weight: 500;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-sm);
    transition: background 0.2s ease;
}

.btn-danger:hover {
    background: #b91c1c;
}

.btn-danger:active {
    transform: scale(0.98);
}

/* ========================================
   Install Prompt
   ======================================== */

.install-prompt {
    position: fixed;
    bottom: var(--spacing-lg);
    left: 50%;
    transform: translateX(-50%);
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: 1rem;
    padding: var(--spacing-lg);
    box-shadow: var(--shadow-lg);
    z-index: 1000;
    max-width: 90%;
    animation: slideUp 0.3s ease;
}

.install-content {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: var(--spacing-md);
    text-align: center;
}

.install-content i {
    font-size: 2rem;
    color: var(--accent-primary);
}

.install-actions {
    display: flex;
    gap: var(--spacing-md);
}

.btn-install,
.btn-dismiss {
    padding: var(--spacing-sm) var(--spacing-lg);
    border: none;
    border-radius: 0.5rem;
    cursor: pointer;
    font-weight: 500;
    transition: all 0.2s ease;
}

.btn-install {
    background: var(--accent-gradient);
    color: white;
}

.btn-install:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
}

.btn-dismiss {
    background: var(--bg-tertiary);
    color: var(--text-secondary);
}

.btn-dismiss:hover {
    background: var(--bg-hover);
    color: var(--text-primary);
}

/* ========================================
   Utility Classes
   ======================================== */

.hidden {
    display: none !important;
}

.loading {
    opacity: 0.6;
    pointer-events: none;
}

/* ========================================
   Scrollbar Styling
   ======================================== */

::-webkit-scrollbar {
    width: 8px;
    height: 8px;
}

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

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

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

/* ========================================
   Responsive Design
   ======================================== */

@media (min-width: 769px) {
    .sidebar {
        left: 0;
    }
    
    .main-content {
        margin-left: 300px;
    }
    
    .input-area {
        left: 300px;
    }
}

@media (max-width: 768px) {
    .app-title {
        font-size: 1.2rem;
    }
    
    .sidebar {
        width: 100%;
        left: -100%;
    }
    
    .message-content {
        max-width: 90%;
    }
    
    .thinking-tree {
        max-width: 90%;
    }
    
    .example-cards {
        grid-template-columns: 1fr;
    }
    
    .welcome-title {
        font-size: 1.5rem;
    }
    
    .welcome-subtitle {
        font-size: 1rem;
    }
}

@media (max-width: 480px) {
    .app-header {
        padding: var(--spacing-sm) var(--spacing-md);
    }
    
    .messages-wrapper {
        padding: var(--spacing-md);
    }
    
    .input-area {
        padding: var(--spacing-md);
    }
    
    .welcome-screen {
        padding: var(--spacing-lg);
        padding-top: var(--spacing-xl);
        padding-bottom: var(--spacing-sm);
        justify-content: flex-start;
    }
    
    .welcome-logo {
        font-size: 3rem;
    }
    
    .welcome-logo-img {
        width: 100px;
        height: 100px;
    }
    
    .example-cards {
        gap: var(--spacing-sm);
    }
}

/* ========================================
   Dark Mode Toggle Support
   ======================================== */

body.light-mode {
    --bg-primary: #ffffff;
    --bg-secondary: #f7f7f8;
    --bg-tertiary: #e7e7e9;
    --bg-hover: #d4d4d8;
    --text-primary: #18181b;
    --text-secondary: #52525b;
    --text-tertiary: #a1a1aa;
    --border-color: #e4e4e7;
    --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.1);
    --shadow-md: 0 4px 6px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 10px 15px rgba(0, 0, 0, 0.1);
}