/* ================================
   DEEP ANSWERING - PROFESSIONAL THEME
   Dark/Light Mode + Advanced 3D Effects
   ================================ */

/* === DARK THEME (Default) === */
:root {
    /* Dark Theme Colors */
    --yt-black: #0f0f0f;
    --yt-dark-gray: #212121;
    --yt-med-gray: #3f3f3f;
    --yt-light-gray: #717171;
    --yt-border: #3d3d3d;
    --yt-white: #f1f1f1;
    --yt-pure-white: #ffffff;
    
    /* Brand Accent */
    --accent: #00d9a3;
    --accent-hover: #00b88a;
    --accent-light: rgba(0, 217, 163, 0.1);
    
    /* Dynamic Colors (change with theme) */
    --bg-primary: var(--yt-black);
    --bg-secondary: var(--yt-dark-gray);
    --bg-hover: var(--yt-med-gray);
    --bg-elevated: #272727;
    
    --text-primary: var(--yt-white);
    --text-secondary: #aaaaaa;
    --text-tertiary: var(--yt-light-gray);
    
    --border-color: var(--yt-border);
    
    /* Spacing */
    --space-xs: 4px;
    --space-sm: 8px;
    --space-md: 12px;
    --space-lg: 16px;
    --space-xl: 24px;
    --space-2xl: 32px;
    --space-3xl: 48px;
    
    /* Border Radius */
    --radius-sm: 4px;
    --radius-md: 8px;
    --radius-lg: 12px;
    --radius-xl: 16px;
    --radius-full: 50%;
    
    /* Shadows for Dark Mode */
    --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.3);
    --shadow-md: 0 2px 4px rgba(0, 0, 0, 0.3);
    --shadow-lg: 0 4px 8px rgba(0, 0, 0, 0.3);
    
    /* 3D Gel/Resin Effect Shadows */
    --gel-shadow-outer: 0 8px 16px rgba(0, 0, 0, 0.4),
                         0 4px 8px rgba(0, 0, 0, 0.3);
    --gel-shadow-inner: inset 0 -4px 8px rgba(0, 0, 0, 0.3),
                         inset 0 2px 4px rgba(255, 255, 255, 0.1);
    --gel-highlight: linear-gradient(135deg, 
                                      rgba(255, 255, 255, 0.3) 0%,
                                      rgba(255, 255, 255, 0.1) 40%,
                                      transparent 70%);
}

/* === LIGHT THEME === */
[data-theme="light"] {
    --yt-black: #ffffff;
    --yt-dark-gray: #f9f9f9;
    --yt-med-gray: #e5e5e5;
    --yt-light-gray: #606060;
    --yt-border: #e0e0e0;
    --yt-white: #0f0f0f;
    --yt-pure-white: #000000;
    
    --bg-primary: #ffffff;
    --bg-secondary: #f9f9f9;
    --bg-hover: #e5e5e5;
    --bg-elevated: #ffffff;
    
    --text-primary: #0f0f0f;
    --text-secondary: #606060;
    --text-tertiary: #909090;
    
    --border-color: #e0e0e0;
    
    /* Shadows for Light Mode */
    --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.08);
    --shadow-md: 0 2px 4px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 4px 8px rgba(0, 0, 0, 0.12);
    
    /* 3D Gel/Resin for Light Mode */
    --gel-shadow-outer: 0 8px 16px rgba(0, 0, 0, 0.15),
                         0 4px 8px rgba(0, 0, 0, 0.1);
    --gel-shadow-inner: inset 0 -4px 8px rgba(0, 0, 0, 0.05),
                         inset 0 2px 4px rgba(255, 255, 255, 0.8);
    --gel-highlight: linear-gradient(135deg, 
                                      rgba(255, 255, 255, 0.9) 0%,
                                      rgba(255, 255, 255, 0.5) 40%,
                                      transparent 70%);
}

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

html {
    scroll-behavior: smooth;
}

body {
    font-family: "Roboto", "Arial", sans-serif;
    line-height: 1.6;
    color: var(--text-primary);
    background-color: var(--bg-primary);
    -webkit-font-smoothing: antialiased;
    transition: background-color 0.3s ease, color 0.3s ease;
}

/* === TYPOGRAPHY === */
h1, h2, h3, h4, h5, h6 {
    font-weight: 500;
    line-height: 1.3;
    color: var(--text-primary);
}

h1 { font-size: 36px; }
h2 { font-size: 24px; }
h3 { font-size: 20px; }
h4 { font-size: 18px; }

p {
    color: var(--text-secondary);
    line-height: 1.8;
}

a {
    color: var(--text-primary);
    text-decoration: none;
    transition: color 0.2s;
}

a:hover {
    color: var(--accent);
}

/* === HEADER === */
.header {
    background-color: var(--bg-primary);
    border-bottom: 1px solid var(--border-color);
    padding: var(--space-lg) 0;
    position: sticky;
    top: 0;
    z-index: 100;
    transition: background-color 0.3s ease, border-color 0.3s ease;
}

.header-container {
    max-width: 1280px;
    margin: 0 auto;
    padding: 0 var(--space-xl);
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: var(--space-md);
}

.logo {
    display: flex;
    align-items: center;
    gap: var(--space-md);
}

.logo-info {
    display: flex;
    flex-direction: column;
    gap: 2px;
}

.logo-img {
    width: 40px;
    height: 40px;
    border-radius: var(--radius-md);
}

/* Apply gel3d to logo */
.logo-img.gel3d {
    box-shadow: var(--gel-shadow-outer), var(--gel-shadow-inner);
}

.logo-text {
    font-size: 22px;
    font-weight: 500;
    color: var(--text-primary);
}

.logo-dates {
    font-size: 11px;
    color: var(--text-tertiary);
    font-weight: 400;
}

/* === HEADER ACTIONS (Responsive like original) === */
.header-actions {
    display: flex;
    align-items: center;
    gap: var(--space-sm);
}

/* Theme Toggle Button */
.theme-toggle {
    width: 40px;
    height: 40px;
    border-radius: var(--radius-full);
    background-color: var(--bg-secondary);
    border: 1px solid var(--border-color);
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all 0.2s;
    font-size: 20px;
}

.theme-toggle:hover {
    background-color: var(--bg-hover);
}

/* Apply gel3d to theme toggle */
.theme-toggle.gel3d {
    box-shadow: var(--gel-shadow-outer), var(--gel-shadow-inner);
}

/* Desktop buttons - hidden on mobile */
.header-buttons {
    display: none;
    gap: var(--space-sm);
}

/* Show on medium+ screens */
@media (min-width: 768px) {
    .header-buttons {
        display: flex;
    }
}

/* Profile icon - visible on all screens */
.profile-icon {
    width: 40px;
    height: 40px;
    border-radius: var(--radius-full);
    background: linear-gradient(135deg, var(--accent) 0%, var(--accent-hover) 100%);
    border: none;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 18px;
    color: white;
    transition: all 0.3s;
}

/* === BUTTONS === */
.btn {
    padding: var(--space-sm) var(--space-lg);
    border-radius: var(--radius-md);
    border: none;
    font-size: 14px;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.2s;
    display: inline-flex;
    align-items: center;
    gap: var(--space-sm);
}

.btn-primary {
    background-color: var(--accent);
    color: var(--yt-black);
}

.btn-primary:hover {
    background-color: var(--accent-hover);
}

.btn-secondary {
    background-color: transparent;
    color: var(--accent);
    border: 1px solid var(--yt-border);
}

.btn-secondary:hover {
    background-color: var(--bg-hover);
}

/* === CONTAINER === */
.container {
    max-width: 1280px;
    margin: 0 auto;
    padding: 0 var(--space-xl);
}

.left-border {
    border-left: 2px solid #717171;
    border-bottom: 2px solid #717171;
    padding-left: 2%;
    padding-bottom: 2%;
}

.section {
    padding: var(--space-3xl) 0;
}

/* === HERO === */
.hero {
    padding: var(--space-3xl) 0 var(--space-2xl);
}

.hero-container {
    max-width: 900px;
}

.hero h1 {
    font-size: 40px;
    font-weight: 400;
    margin-bottom: var(--space-lg);
    line-height: 1.2;
    text-align: left;
}

.hero p {
    font-size: 16px;
    color: var(--text-secondary);
    margin-bottom: var(--space-md);
    text-align: left;
    line-height: 1.8;
}

/* === CARDS === */
.card {
    background-color: var(--bg-secondary);
    border-radius: var(--radius-lg);
    padding: var(--space-lg);
    transition: all 0.3s;
    border: 1px solid transparent;
}

.card:hover {
    background-color: var(--bg-hover);
    border-color: var(--border-color);
}

/* === TOPIC SECTION === */
.topic-section {
    margin-bottom: var(--space-3xl);
}

.topic-header {
    margin-bottom: var(--space-xl);
}

.topic-header h2 {
    font-weight: 500;
    margin-bottom: var(--space-sm);
}

.topic-header p {
    color: var(--text-secondary);
}

.topic-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: var(--space-lg);
}

.topic-card {
    background-color: var(--bg-secondary);
    border-radius: var(--radius-lg);
    padding: var(--space-lg);
    transition: all 0.3s;
    cursor: pointer;
    border: 1px solid transparent;
}

/* Apply gel3d to topic cards on hover */
.topic-card:hover {
    background-color: var(--bg-hover);
    border-color: var(--border-color);
    transform: translateY(-4px);
    box-shadow: var(--gel-shadow-outer);
}

.topic-card h3 {
    font-size: 18px;
    font-weight: 500;
    margin-bottom: var(--space-md);
    color: var(--text-primary);
}

.topic-card p {
    font-size: 14px;
    color: var(--text-secondary);
    margin-bottom: var(--space-xs);
    line-height: 1.6;
}

.topic-badge {
    display: inline-block;
    padding: var(--space-xs) var(--space-sm);
    background-color: var(--bg-hover);
    border-radius: var(--radius-sm);
    font-size: 12px;
    color: var(--text-tertiary);
    margin-bottom: var(--space-md);
}

/* === FOLDER SYSTEM UI === */
.folder-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
    gap: var(--space-xl);
}

.folder-item {
    text-align: center;
    cursor: pointer;
    transition: all 0.3s;
    padding: var(--space-lg);
    border-radius: var(--radius-lg);
}

.folder-item:hover {
    background-color: var(--bg-secondary);
}

.folder-icon {
    width: 80px;
    height: 80px;
    margin: 0 auto var(--space-md);
    position: relative;
    transition: all 0.3s;
}

/* Folder visual */
.folder-visual {
    width: 100%;
    height: 100%;
    background: linear-gradient(135deg, var(--accent) 0%, var(--accent-hover) 100%);
    border-radius: var(--radius-md) var(--radius-md) var(--radius-sm) var(--radius-sm);
    position: relative;
    box-shadow: var(--gel-shadow-outer), var(--gel-shadow-inner);
}

/* Folder tab */
.folder-visual::before {
    content: '';
    position: absolute;
    top: -8px;
    left: 0;
    width: 50%;
    height: 12px;
    background: linear-gradient(135deg, var(--accent) 0%, var(--accent-hover) 100%);
    border-radius: var(--radius-sm) var(--radius-sm) 0 0;
}

/* Folder highlight */
.folder-visual::after {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    border-radius: inherit;
    background: var(--gel-highlight);
    pointer-events: none;
}

.folder-item:hover .folder-icon {
    transform: translateY(-4px) scale(1.05);
}

.folder-label {
    font-size: 14px;
    font-weight: 500;
    color: var(--text-primary);
}

.folder-count {
    font-size: 12px;
    color: var(--text-tertiary);
    margin-top: var(--space-xs);
}

/* === FORMS === */
.form-section {
    background-color: var(--bg-secondary);
    border-radius: var(--radius-lg);
    padding: var(--space-2xl);
    max-width: 700px;
    margin: 0 auto;
    border: 1px solid var(--border-color);
}

.form-group {
    margin-bottom: var(--space-lg);
}

.form-label {
    display: block;
    font-size: 14px;
    color: var(--text-secondary);
    margin-bottom: var(--space-sm);
}

.form-input,
.form-textarea {
    width: 100%;
    padding: var(--space-md);
    background-color: var(--bg-primary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-sm);
    color: var(--text-primary);
    font-size: 14px;
    font-family: inherit;
    transition: all 0.2s;
}

.form-input:focus,
.form-textarea:focus {
    outline: none;
    border-color: var(--accent);
    box-shadow: 0 0 0 3px var(--accent-light);
}

.form-textarea {
    resize: vertical;
    min-height: 100px;
}

/* === FOOTER === */
.footer {
    background-color: var(--bg-secondary);
    border-top: 1px solid var(--border-color);
    padding: var(--space-2xl) 0;
    margin-top: var(--space-3xl);
}

.footer-content {
    text-align: center;
    color: var(--text-tertiary);
    font-size: 14px;
}

/* === UTILITY CLASSES === */
.text-center {
    text-align: center;
}

.mb-sm { margin-bottom: var(--space-sm); }
.mb-md { margin-bottom: var(--space-md); }
.mb-lg { margin-bottom: var(--space-lg); }
.mb-xl { margin-bottom: var(--space-xl); }
.mb-2xl { margin-bottom: var(--space-2xl); }

.mt-sm { margin-top: var(--space-sm); }
.mt-md { margin-top: var(--space-md); }
.mt-lg { margin-top: var(--space-lg); }
.mt-xl { margin-top: var(--space-xl); }

/* === RESPONSIVE === */
@media (max-width: 768px) {
    .topic-grid {
        grid-template-columns: 1fr;
    }
    
    .folder-grid {
        grid-template-columns: repeat(auto-fill, minmax(150px, 1fr));
    }
    
    .hero h1 {
        font-size: 32px;
    }
    
    .header-container {
        padding: 0 var(--space-lg);
    }
    
    .container {
        padding: 0 var(--space-lg);
    }
}

/* === SMOOTH TRANSITIONS === */
* {
    transition-property: background-color, border-color, color, fill, stroke;
    transition-duration: 0.3s;
    transition-timing-function: ease;
}

button, a, .topic-card, .folder-item {
    transition-property: all;
}