/* --- CSS Variables & Design Tokens --- */
:root {
    /* Dark theme (default) */
    --bg: #0f172a;
    --page-bg: radial-gradient(circle at 10% 20%, rgba(139, 92, 246, 0.12) 0%, transparent 40%),
               radial-gradient(circle at 90% 80%, rgba(59, 130, 246, 0.12) 0%, transparent 45%),
               #0b0f19;
    --panel-bg: rgba(30, 41, 59, 0.45);
    --surface: #1e293b;
    --overlay-bg: rgba(15, 23, 42, 0.7);
    
    --card-bg: rgba(255, 255, 255, 0.03);
    --card-bg-hover: rgba(255, 255, 255, 0.06);
    --subtle-bg: rgba(255, 255, 255, 0.05);
    --subtle-bg-hover: rgba(255, 255, 255, 0.1);
    --chip-bg: rgba(255, 255, 255, 0.04);
    --input-bg: rgba(15, 23, 42, 0.6);
    --inset-bg: rgba(15, 23, 42, 0.4);
    --inset-bg-soft: rgba(15, 23, 42, 0.2);
    
    --border-color: rgba(255, 255, 255, 0.08);
    --border-highlight: rgba(255, 255, 255, 0.15);
    
    --text-primary: #f8fafc;
    --text-secondary: #cbd5e1;
    --text-muted: #64748b;
    --faint-icon: rgba(255, 255, 255, 0.05);
    
    --primary-gradient: linear-gradient(135deg, #8b5cf6 0%, #3b82f6 100%);
    --title-gradient: linear-gradient(to right, #fff, #a78bfa);
    --accent-glow: rgba(139, 92, 246, 0.15);
    
    --color-purple: #a78bfa;
    --color-cyan: #22d3ee;
    --color-emerald: #34d399;
    --color-rose: #fb7185;
    
    --shadow-soft: 0 10px 25px rgba(0, 0, 0, 0.5);
    --shadow-modal: 0 20px 50px rgba(0, 0, 0, 0.6);
    --scrollbar-thumb: rgba(255, 255, 255, 0.08);
    --scrollbar-thumb-hover: rgba(255, 255, 255, 0.15);
    
    --font-heading: 'Outfit', sans-serif;
    --font-body: 'Plus Jakarta Sans', sans-serif;
    
    --transition-fast: 0.2s ease;
    --transition-normal: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    --border-radius: 16px;
}

/* Light theme overrides */
html[data-theme="light"] {
    --bg: #eef2f7;
    --page-bg: radial-gradient(circle at 10% 20%, rgba(139, 92, 246, 0.08) 0%, transparent 40%),
               radial-gradient(circle at 90% 80%, rgba(59, 130, 246, 0.08) 0%, transparent 45%),
               #f1f5f9;
    --panel-bg: rgba(255, 255, 255, 0.8);
    --surface: #ffffff;
    --overlay-bg: rgba(15, 23, 42, 0.4);
    
    --card-bg: rgba(15, 23, 42, 0.03);
    --card-bg-hover: rgba(139, 92, 246, 0.06);
    --subtle-bg: rgba(15, 23, 42, 0.05);
    --subtle-bg-hover: rgba(15, 23, 42, 0.1);
    --chip-bg: rgba(15, 23, 42, 0.04);
    --input-bg: #ffffff;
    --inset-bg: rgba(15, 23, 42, 0.05);
    --inset-bg-soft: rgba(15, 23, 42, 0.03);
    
    --border-color: rgba(15, 23, 42, 0.1);
    --border-highlight: rgba(15, 23, 42, 0.2);
    
    --text-primary: #0f172a;
    --text-secondary: #475569;
    --text-muted: #94a3b8;
    --faint-icon: rgba(15, 23, 42, 0.1);
    
    --title-gradient: linear-gradient(to right, #1e293b, #7c3aed);
    
    --color-purple: #7c3aed;
    --color-cyan: #0891b2;
    --color-emerald: #059669;
    --color-rose: #e11d48;
    
    --shadow-soft: 0 10px 25px rgba(15, 23, 42, 0.12);
    --shadow-modal: 0 20px 50px rgba(15, 23, 42, 0.25);
    --scrollbar-thumb: rgba(15, 23, 42, 0.15);
    --scrollbar-thumb-hover: rgba(15, 23, 42, 0.3);
}

/* --- Base & Reset --- */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    -webkit-tap-highlight-color: transparent;
}

body {
    background-color: var(--bg);
    color: var(--text-primary);
    font-family: var(--font-body);
    min-height: 100vh;
    overflow-x: hidden;
    position: relative;
    transition: background-color 0.3s ease, color 0.3s ease;
}

/* --- Background Glow Blobs --- */
.glass-bg {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    z-index: -1;
    background: var(--page-bg);
    transition: background 0.3s ease;
}

/* --- App Container & Layout --- */
.app-container {
    max-width: 1440px;
    margin: 0 auto;
    display: flex;
    flex-direction: column;
    height: 100vh;
    padding: 16px;
}

/* --- Header Section --- */
.app-header {
    background: var(--panel-bg);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius);
    padding: 12px 24px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 16px;
    z-index: 10;
}

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

.logo-icon {
    width: 42px;
    height: 42px;
    border-radius: 12px;
    background: var(--primary-gradient);
    color: #fff;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.2rem;
    box-shadow: 0 4px 15px rgba(139, 92, 246, 0.3);
    flex-shrink: 0;
}

.logo-text h1 {
    font-family: var(--font-heading);
    font-size: 1.25rem;
    font-weight: 700;
    letter-spacing: 0.5px;
}

.logo-text span {
    font-size: 0.75rem;
    color: var(--text-secondary);
    font-weight: 400;
}

.byline {
    color: var(--color-purple);
    font-weight: 700;
    text-decoration: none;
}

.byline:hover {
    text-decoration: underline;
}

/* Navigation */
.app-nav {
    display: flex;
    gap: 8px;
    background: var(--inset-bg);
    padding: 4px;
    border-radius: 12px;
    border: 1px solid var(--border-color);
}

.nav-btn {
    background: transparent;
    border: none;
    color: var(--text-secondary);
    font-family: var(--font-body);
    font-size: 0.85rem;
    font-weight: 600;
    padding: 8px 16px;
    border-radius: 8px;
    cursor: pointer;
    display: flex;
    align-items: center;
    gap: 8px;
    transition: var(--transition-fast);
}

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

.nav-btn.active {
    color: #fff;
    background: var(--primary-gradient);
    box-shadow: 0 4px 12px rgba(59, 130, 246, 0.2);
}

.badge {
    background: var(--subtle-bg-hover);
    padding: 1px 6px;
    border-radius: 12px;
    font-size: 0.7rem;
}

.nav-btn.active .badge {
    background: rgba(255, 255, 255, 0.25);
}

/* Header Actions & Settings Dropdown */
.header-actions {
    position: relative;
    display: flex;
    gap: 8px;
    align-items: center;
}

.action-btn {
    width: 38px;
    height: 38px;
    border-radius: 10px;
    background: var(--subtle-bg);
    border: 1px solid var(--border-color);
    color: var(--text-primary);
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: var(--transition-fast);
    flex-shrink: 0;
}

.action-btn:hover {
    background: var(--subtle-bg-hover);
    border-color: var(--border-highlight);
}

.settings-dropdown {
    position: absolute;
    top: calc(100% + 10px);
    right: 0;
    width: 280px;
    background: var(--surface);
    border: 1px solid var(--border-highlight);
    border-radius: 12px;
    padding: 16px;
    display: none;
    flex-direction: column;
    gap: 12px;
    z-index: 100;
    box-shadow: var(--shadow-soft);
}

.settings-dropdown.active {
    display: flex;
}

.settings-dropdown h3 {
    font-family: var(--font-heading);
    font-size: 1rem;
    border-bottom: 1px solid var(--border-color);
    padding-bottom: 8px;
}

.setting-item {
    display: flex;
    flex-direction: column;
    gap: 6px;
}

.setting-item label {
    font-size: 0.8rem;
    color: var(--text-secondary);
}

.setting-item input[type="range"] {
    width: 100%;
    cursor: pointer;
    accent-color: #8b5cf6;
}

.range-labels {
    display: flex;
    justify-content: space-between;
    font-size: 0.7rem;
    color: var(--text-muted);
}

.setting-note {
    font-size: 0.7rem;
    color: var(--text-muted);
    line-height: 1.3;
    display: flex;
    gap: 6px;
}

.setting-note i {
    font-size: 0.8rem;
    color: var(--color-purple);
}

/* --- Mobile Bottom Navigation --- */
.mobile-nav {
    position: fixed;
    bottom: 0;
    left: 0;
    right: 0;
    display: none;
    justify-content: space-around;
    gap: 4px;
    background: var(--surface);
    border-top: 1px solid var(--border-color);
    padding: 8px 10px calc(8px + env(safe-area-inset-bottom));
    z-index: 500;
    box-shadow: 0 -4px 20px rgba(0, 0, 0, 0.15);
}

.mobile-nav .nav-btn {
    flex-direction: column;
    gap: 4px;
    font-size: 0.68rem;
    padding: 6px 12px;
    flex: 1;
    max-width: 140px;
    position: relative;
}

.mobile-nav .nav-btn i {
    font-size: 1.1rem;
}

.mobile-nav .nav-btn.active {
    background: transparent;
    color: var(--color-purple);
    box-shadow: none;
}

.mobile-nav .nav-btn .badge {
    position: absolute;
    top: 0;
    right: calc(50% - 22px);
    background: var(--primary-gradient);
    color: #fff;
    font-size: 0.6rem;
    min-width: 16px;
    text-align: center;
}

/* --- Main Layout & Tabs --- */
.app-main {
    flex: 1;
    position: relative;
    overflow: hidden;
}

.tab-content {
    display: none;
    height: 100%;
}

.tab-content.active {
    display: block;
}

/* --- TAB 1: Search & Chat Grid --- */
/* Equal halves: raw results deserve as much space as the chat */
.search-layout {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 16px;
    height: 100%;
}

/* Left: Chat interface */
.chat-container {
    background: var(--panel-bg);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius);
    display: flex;
    flex-direction: column;
    height: 100%;
    overflow: hidden;
    position: relative;
}

.welcome-box {
    padding: 32px;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    text-align: center;
    gap: 16px;
    flex: 1;
    overflow-y: auto;
}

.welcome-box h2 {
    font-family: var(--font-heading);
    font-size: 1.8rem;
    background: var(--title-gradient);
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
}

.welcome-box p {
    font-size: 0.95rem;
    color: var(--text-secondary);
    max-width: 580px;
    line-height: 1.6;
}

.coverage-note {
    font-size: 0.78rem;
    color: var(--text-muted);
    display: flex;
    align-items: center;
    gap: 6px;
    background: var(--subtle-bg);
    border: 1px solid var(--border-color);
    border-radius: 20px;
    padding: 6px 14px;
}

.coverage-note i {
    color: var(--color-purple);
    font-size: 0.8rem;
}

.suggested-queries {
    margin-top: 16px;
    width: 100%;
    max-width: 500px;
}

.suggested-queries h4 {
    font-size: 0.8rem;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 1px;
    margin-bottom: 12px;
}

.suggestions-list {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: 8px;
}

.suggest-btn {
    background: var(--chip-bg);
    border: 1px solid var(--border-color);
    color: var(--text-secondary);
    padding: 8px 14px;
    border-radius: 20px;
    font-family: var(--font-body);
    font-size: 0.8rem;
    cursor: pointer;
    transition: var(--transition-fast);
}

.suggest-btn:hover {
    background: rgba(139, 92, 246, 0.1);
    border-color: rgba(139, 92, 246, 0.4);
    color: var(--text-primary);
}

/* Chat Messages */
.chat-messages {
    flex: 1;
    overflow-y: auto;
    padding: 24px;
    display: flex;
    flex-direction: column;
    gap: 20px;
    scroll-behavior: smooth;
    display: none; /* Shown only when messages present */
}

.message-wrapper {
    display: flex;
    flex-direction: column;
    max-width: 85%;
    animation: slideUp 0.3s ease;
    flex-shrink: 0;
}

.message-wrapper.user {
    align-self: flex-end;
}

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

.message-label {
    font-size: 0.75rem;
    color: var(--text-muted);
    margin-bottom: 4px;
    font-weight: 600;
}

.message-wrapper.user .message-label {
    text-align: right;
}

.message-bubble {
    padding: 16px 20px;
    border-radius: 18px;
    line-height: 1.5;
    font-size: 0.92rem;
}

.message-wrapper.user .message-bubble {
    background: var(--primary-gradient);
    color: #fff;
    border-bottom-right-radius: 4px;
}

.message-wrapper.assistant .message-bubble {
    background: var(--subtle-bg);
    border: 1px solid var(--border-color);
    border-bottom-left-radius: 4px;
    color: var(--text-primary);
}

/* RAG answer formatting in bubble */
.message-bubble h1, .message-bubble h2, .message-bubble h3 {
    font-family: var(--font-heading);
    margin: 12px 0 6px 0;
    color: var(--color-purple);
}
.message-bubble h1:first-child, .message-bubble h2:first-child, .message-bubble h3:first-child {
    margin-top: 0;
}
.message-bubble p {
    margin-bottom: 10px;
}
.message-bubble p:last-child {
    margin-bottom: 0;
}
.message-bubble ul, .message-bubble ol {
    margin-left: 20px;
    margin-bottom: 10px;
}
.message-bubble li {
    margin-bottom: 4px;
}

/* Clickable [n] citations in chat answers */
.cite-link {
    color: var(--color-purple);
    font-weight: 700;
    text-decoration: none;
    border-bottom: 1px dashed rgba(167, 139, 250, 0.5);
    cursor: pointer;
}

.cite-link:hover {
    color: var(--text-primary);
    background: rgba(139, 92, 246, 0.2);
    border-radius: 3px;
}

/* Loading/Thinking Bubble */
.typing-indicator {
    display: flex;
    gap: 4px;
    padding: 8px 12px;
}
.typing-indicator span {
    width: 6px;
    height: 6px;
    background: var(--text-muted);
    border-radius: 50%;
    animation: typing 1s infinite alternate;
}
.typing-indicator span:nth-child(2) { animation-delay: 0.2s; }
.typing-indicator span:nth-child(3) { animation-delay: 0.4s; }

/* Input Bar */
.search-bar-container {
    padding: 16px;
    background: var(--inset-bg-soft);
    border-top: 1px solid var(--border-color);
}

.input-wrapper {
    position: relative;
    display: flex;
    align-items: center;
    background: var(--input-bg);
    border: 1px solid var(--border-color);
    border-radius: 12px;
    padding: 6px;
    transition: var(--transition-fast);
}

.input-wrapper:focus-within {
    border-color: rgba(139, 92, 246, 0.6);
    box-shadow: 0 0 15px rgba(139, 92, 246, 0.1);
}

.keyboard-icon {
    position: absolute;
    left: 16px;
    color: var(--text-muted);
}

.input-wrapper input {
    flex: 1;
    min-width: 0;
    background: transparent;
    border: none;
    outline: none;
    color: var(--text-primary);
    padding: 12px 12px 12px 42px;
    font-family: var(--font-body);
    font-size: 0.95rem;
}

.search-action-btn {
    border: none;
    cursor: pointer;
    font-family: var(--font-body);
    font-weight: 600;
    font-size: 0.82rem;
    padding: 10px 16px;
    border-radius: 8px;
    display: flex;
    align-items: center;
    gap: 6px;
    margin-left: 6px;
    transition: var(--transition-fast);
    white-space: nowrap;
    flex-shrink: 0;
}

.search-only-btn {
    background: var(--subtle-bg);
    border: 1px solid var(--border-color);
    color: var(--text-primary);
}
.search-only-btn:hover {
    background: var(--subtle-bg-hover);
}

.chat-ai-btn {
    background: var(--primary-gradient);
    color: #fff;
}
.chat-ai-btn:hover {
    opacity: 0.9;
    transform: translateY(-1px);
}

/* Right: Results Sidebar */
.results-sidebar {
    background: var(--panel-bg);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius);
    display: flex;
    flex-direction: column;
    height: 100%;
    overflow: hidden;
}

.sidebar-header {
    padding: 16px 20px;
    border-bottom: 1px solid var(--border-color);
    display: flex;
    justify-content: space-between;
    align-items: center;
    background: var(--inset-bg-soft);
}

.sidebar-header h3 {
    font-family: var(--font-heading);
    font-size: 1.05rem;
}

.results-count {
    font-size: 0.75rem;
    color: var(--text-muted);
    font-weight: 500;
}

.results-list {
    flex: 1;
    overflow-y: auto;
    padding: 16px;
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.empty-results {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    color: var(--text-muted);
    gap: 12px;
    height: 250px;
    text-align: center;
    padding: 20px;
}

.empty-results i {
    font-size: 2.2rem;
    color: var(--faint-icon);
}

.empty-results p {
    font-size: 0.85rem;
}

/* --- Paper Cards (General) --- */
.paper-card {
    background: var(--card-bg);
    border: 1px solid var(--border-color);
    border-radius: 12px;
    padding: 14px;
    cursor: pointer;
    transition: var(--transition-fast);
    display: flex;
    flex-direction: column;
    gap: 8px;
    position: relative;
    overflow: hidden;
    flex-shrink: 0; /* Prevent collapse inside scrollable flex column */
}

.paper-card:hover {
    background: var(--card-bg-hover);
    border-color: var(--border-highlight);
    transform: translateY(-2px);
}

.card-top {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    gap: 8px;
}

.card-num {
    font-size: 0.7rem;
    color: var(--text-muted);
    font-weight: 700;
    letter-spacing: 0.5px;
}

.mode-badge {
    font-size: 0.65rem;
    padding: 2px 8px;
    border-radius: 10px;
    font-weight: 700;
    text-transform: uppercase;
}

.mode-badge.in-person {
    background: rgba(52, 211, 153, 0.12);
    color: var(--color-emerald);
    border: 1px solid rgba(52, 211, 153, 0.25);
}

.mode-badge.virtual {
    background: rgba(34, 211, 238, 0.12);
    color: var(--color-cyan);
    border: 1px solid rgba(34, 211, 238, 0.25);
}

.mode-badge.none {
    background: rgba(251, 113, 133, 0.12);
    color: var(--color-rose);
    border: 1px solid rgba(251, 113, 133, 0.25);
}

.paper-title {
    font-family: var(--font-heading);
    font-size: 0.92rem;
    font-weight: 600;
    line-height: 1.4;
    color: var(--text-primary);
}

.paper-authors {
    font-size: 0.78rem;
    color: var(--text-secondary);
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

.card-meta {
    display: flex;
    align-items: center;
    flex-wrap: wrap;
    gap: 8px 12px;
    font-size: 0.72rem;
    color: var(--text-muted);
    margin-top: 4px;
}

.card-meta span {
    display: flex;
    align-items: center;
    gap: 4px;
}

.card-meta i {
    font-size: 0.8rem;
}

.star-btn {
    background: transparent;
    border: none;
    color: var(--text-muted);
    cursor: pointer;
    font-size: 1rem;
    padding: 4px;
    transition: var(--transition-fast);
}

.star-btn:hover {
    color: var(--color-purple);
}

.star-btn.starred {
    color: #fbbf24; /* Amber star */
    animation: popStar 0.3s ease;
}

.rrf-score-tag {
    position: absolute;
    right: 12px;
    bottom: 12px;
    font-size: 0.6rem;
    background: rgba(139, 92, 246, 0.1);
    color: var(--color-purple);
    padding: 1px 4px;
    border-radius: 4px;
}

/* --- TAB 2: Schedule View --- */
.schedule-container {
    background: var(--panel-bg);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius);
    height: 100%;
    display: flex;
    flex-direction: column;
    overflow: hidden;
}

.schedule-header {
    padding: 24px;
    border-bottom: 1px solid var(--border-color);
    display: flex;
    flex-direction: column;
    gap: 16px;
    background: var(--inset-bg-soft);
}

.schedule-header h2 {
    font-family: var(--font-heading);
    font-size: 1.5rem;
}

.schedule-header p {
    font-size: 0.9rem;
    color: var(--text-secondary);
}

.schedule-filters {
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 16px;
}

.day-selector {
    display: flex;
    gap: 8px;
    background: var(--inset-bg);
    padding: 4px;
    border-radius: 10px;
    border: 1px solid var(--border-color);
}

.day-btn {
    background: transparent;
    border: none;
    color: var(--text-secondary);
    padding: 6px 14px;
    border-radius: 6px;
    font-family: var(--font-body);
    font-size: 0.8rem;
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition-fast);
}

.day-btn.active {
    background: var(--primary-gradient);
    color: #fff;
}

.filter-controls {
    display: flex;
    gap: 10px;
    align-items: center;
}

.search-box {
    position: relative;
    display: flex;
    align-items: center;
    background: var(--input-bg);
    border: 1px solid var(--border-color);
    border-radius: 8px;
    padding: 0 12px;
}

.search-box i {
    color: var(--text-muted);
}

.search-box input {
    background: transparent;
    border: none;
    outline: none;
    color: var(--text-primary);
    padding: 8px 8px 8px 4px;
    font-family: var(--font-body);
    font-size: 0.82rem;
    width: 180px;
}

.select-filter {
    background: var(--input-bg);
    border: 1px solid var(--border-color);
    color: var(--text-primary);
    border-radius: 8px;
    padding: 8px 12px;
    font-family: var(--font-body);
    font-size: 0.82rem;
    outline: none;
    cursor: pointer;
}

.schedule-loading {
    padding: 60px;
    text-align: center;
    font-size: 1rem;
    color: var(--text-muted);
}

.sessions-wrapper {
    flex: 1;
    overflow-y: auto;
    padding: 20px;
    display: flex;
    flex-direction: column;
    gap: 16px;
}

/* Accordion Section */
.session-accordion {
    background: var(--card-bg);
    border: 1px solid var(--border-color);
    border-radius: 12px;
    overflow: hidden;
    transition: var(--transition-fast);
    flex-shrink: 0;
}

.accordion-header {
    padding: 16px 20px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    cursor: pointer;
    user-select: none;
    transition: var(--transition-fast);
    gap: 16px;
}

.accordion-header:hover {
    background: var(--subtle-bg);
}

.accordion-title-block {
    display: flex;
    flex-direction: column;
    gap: 4px;
    flex: 1;
    min-width: 0;
}

.accordion-title-block h3 {
    font-family: var(--font-heading);
    font-size: 1rem;
    font-weight: 600;
}

.accordion-sub-meta {
    display: flex;
    flex-wrap: wrap;
    gap: 6px 12px;
    font-size: 0.75rem;
    color: var(--text-muted);
}

.accordion-sub-meta span {
    display: flex;
    align-items: center;
    gap: 4px;
}

.accordion-actions {
    display: flex;
    align-items: center;
    gap: 10px;
    flex-shrink: 0;
}

.btn-ics-export {
    background: var(--subtle-bg);
    border: 1px solid var(--border-color);
    color: var(--text-secondary);
    padding: 6px 12px;
    border-radius: 6px;
    font-family: var(--font-body);
    font-size: 0.72rem;
    cursor: pointer;
    font-weight: 600;
    transition: var(--transition-fast);
    display: flex;
    align-items: center;
    gap: 5px;
    white-space: nowrap;
}

.btn-ics-export:hover {
    background: var(--primary-gradient);
    color: #fff;
    border-color: transparent;
}

.accordion-icon {
    font-size: 0.95rem;
    color: var(--text-muted);
    transition: transform var(--transition-normal);
}

.session-accordion.expanded .accordion-icon {
    transform: rotate(180deg);
}

.accordion-body {
    display: none;
    border-top: 1px solid var(--border-color);
    padding: 16px;
    background: var(--inset-bg-soft);
}

.session-accordion.expanded .accordion-body {
    display: block;
}

.accordion-papers-list {
    display: flex;
    flex-direction: column;
    gap: 8px;
}

.accordion-paper-row {
    background: var(--card-bg);
    padding: 10px 14px;
    border-radius: 8px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    cursor: pointer;
    border: 1px solid transparent;
    transition: var(--transition-fast);
    flex-shrink: 0;
}

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

.accordion-paper-details {
    display: flex;
    flex-direction: column;
    gap: 2px;
    flex: 1;
    margin-right: 16px;
    min-width: 0;
}

.accordion-paper-details h4 {
    font-size: 0.88rem;
    color: var(--text-primary);
}

.accordion-paper-details span {
    font-size: 0.75rem;
    color: var(--text-secondary);
}

/* --- TAB 3: My Schedule (Starred) Layout --- */
.starred-container {
    background: var(--panel-bg);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius);
    height: 100%;
    display: flex;
    flex-direction: column;
    overflow: hidden;
}

.starred-header {
    padding: 24px;
    border-bottom: 1px solid var(--border-color);
    display: flex;
    flex-direction: column;
    gap: 8px;
    background: var(--inset-bg-soft);
}

.starred-title-row {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.starred-header h2 {
    font-family: var(--font-heading);
    font-size: 1.5rem;
}

.starred-header p {
    font-size: 0.9rem;
    color: var(--text-secondary);
}

.btn-primary {
    background: var(--primary-gradient);
    border: none;
    color: #fff;
    cursor: pointer;
    font-family: var(--font-body);
    font-weight: 600;
    font-size: 0.85rem;
    padding: 10px 18px;
    border-radius: 8px;
    display: flex;
    align-items: center;
    gap: 8px;
    transition: var(--transition-fast);
}

.btn-primary:hover {
    box-shadow: 0 4px 15px rgba(139, 92, 246, 0.3);
    opacity: 0.95;
}

.starred-list {
    flex: 1;
    overflow-y: auto;
    padding: 20px;
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.day-heading {
    display: flex;
    align-items: center;
    gap: 10px;
    padding: 8px 4px 2px 4px;
    flex-shrink: 0;
}

.day-heading:not(:first-child) {
    margin-top: 12px;
    border-top: 1px solid var(--border-color);
    padding-top: 18px;
}

.day-heading i {
    color: var(--color-purple);
    font-size: 1rem;
}

.day-heading h3 {
    font-family: var(--font-heading);
    font-size: 1.15rem;
    font-weight: 700;
}

.day-heading .badge {
    background: rgba(139, 92, 246, 0.15);
    color: var(--color-purple);
    font-weight: 600;
}

.empty-starred {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    color: var(--text-muted);
    gap: 12px;
    padding: 60px;
    text-align: center;
}

.empty-starred i {
    font-size: 3rem;
    color: var(--faint-icon);
}

.empty-starred p {
    font-size: 0.9rem;
}

/* --- Paper Modal Dialog --- */
.modal {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: var(--overlay-bg);
    backdrop-filter: blur(8px);
    -webkit-backdrop-filter: blur(8px);
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 16px;
    z-index: 1000;
    opacity: 0;
    visibility: hidden;
    transition: opacity 0.3s ease, visibility 0.3s ease;
}

.modal.active {
    opacity: 1;
    visibility: visible;
}

.modal-content {
    background: var(--surface);
    border: 1px solid var(--border-highlight);
    border-radius: 20px;
    max-width: 680px;
    width: 100%;
    max-height: 85vh;
    display: flex;
    flex-direction: column;
    box-shadow: var(--shadow-modal);
    transform: translateY(20px);
    transition: transform 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

.modal.active .modal-content {
    transform: translateY(0);
}

.modal-header {
    padding: 20px 24px;
    border-bottom: 1px solid var(--border-color);
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.modal-paper-id {
    font-size: 0.75rem;
    background: var(--subtle-bg);
    padding: 2px 8px;
    border-radius: 4px;
    font-weight: 700;
    color: var(--text-muted);
}

.close-modal {
    background: transparent;
    border: none;
    color: var(--text-secondary);
    font-size: 1.25rem;
    cursor: pointer;
    transition: var(--transition-fast);
}

.close-modal:hover {
    color: var(--color-rose);
}

.modal-body {
    padding: 24px;
    overflow-y: auto;
    display: flex;
    flex-direction: column;
    gap: 16px;
}

.modal-body h2 {
    font-family: var(--font-heading);
    font-size: 1.4rem;
    color: var(--text-primary);
}

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

.modal-metadata-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 12px;
    margin-top: 10px;
}

.meta-item {
    background: var(--card-bg);
    border: 1px solid var(--border-color);
    padding: 10px 14px;
    border-radius: 8px;
    display: flex;
    align-items: center;
    gap: 12px;
}

.meta-item i {
    font-size: 1.2rem;
    color: var(--color-purple);
}

.meta-item strong {
    display: block;
    font-size: 0.65rem;
    text-transform: uppercase;
    color: var(--text-muted);
}

.meta-item span {
    font-size: 0.78rem;
    color: var(--text-primary);
    font-weight: 600;
}

.modal-abstract-section h3 {
    font-family: var(--font-heading);
    font-size: 1rem;
    margin-bottom: 8px;
    color: var(--color-purple);
}

.modal-abstract-section p {
    font-size: 0.88rem;
    color: var(--text-secondary);
    line-height: 1.6;
}

.modal-footer {
    padding: 20px 24px;
    border-top: 1px solid var(--border-color);
    display: flex;
    justify-content: flex-end;
    flex-wrap: wrap;
    gap: 8px;
}

.modal-action-btn {
    background: var(--subtle-bg);
    border: 1px solid var(--border-color);
    color: var(--text-primary);
    padding: 8px 16px;
    border-radius: 8px;
    font-family: var(--font-body);
    font-size: 0.82rem;
    cursor: pointer;
    font-weight: 600;
    transition: var(--transition-fast);
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 6px;
    text-decoration: none;
}

.modal-action-btn:hover {
    background: var(--subtle-bg-hover);
    border-color: var(--border-highlight);
}

.modal-action-btn.primary-action {
    background: var(--primary-gradient);
    color: #fff;
    border: none;
}

.modal-action-btn.primary-action:hover {
    box-shadow: 0 4px 12px rgba(139, 92, 246, 0.3);
}

.calendar-dropdown-container {
    position: relative;
}

.cal-dropdown {
    position: absolute;
    bottom: calc(100% + 8px);
    right: 0;
    background: var(--surface);
    border: 1px solid var(--border-highlight);
    border-radius: 8px;
    width: 200px;
    padding: 4px;
    box-shadow: var(--shadow-soft);
    display: none;
    flex-direction: column;
    z-index: 1001;
}

.cal-dropdown.active {
    display: flex;
}

.cal-dropdown a {
    color: var(--text-secondary);
    padding: 8px 12px;
    text-decoration: none;
    font-size: 0.8rem;
    border-radius: 6px;
    display: flex;
    align-items: center;
    gap: 8px;
}

.cal-dropdown a:hover {
    background: var(--subtle-bg);
    color: var(--text-primary);
}

/* --- Toast Notification --- */
.app-toast {
    position: fixed;
    bottom: calc(90px + env(safe-area-inset-bottom));
    left: 50%;
    transform: translateX(-50%) translateY(10px);
    background: var(--surface);
    color: var(--text-primary);
    border: 1px solid var(--border-highlight);
    border-radius: 24px;
    padding: 10px 20px;
    font-size: 0.85rem;
    font-weight: 600;
    box-shadow: var(--shadow-soft);
    z-index: 2000;
    opacity: 0;
    visibility: hidden;
    transition: opacity 0.25s ease, transform 0.25s ease, visibility 0.25s ease;
}

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

/* --- Add to Home Screen Banner --- */
.install-banner {
    position: fixed;
    left: 10px;
    right: 10px;
    /* Sits just above the mobile bottom nav */
    bottom: calc(70px + env(safe-area-inset-bottom));
    background: var(--surface);
    border: 1px solid var(--border-highlight);
    border-radius: 14px;
    box-shadow: var(--shadow-soft);
    padding: 12px 14px;
    display: none;
    align-items: center;
    gap: 12px;
    z-index: 400;
    animation: slideUp 0.3s ease;
}

.install-banner.visible {
    display: flex;
}

.install-banner img {
    width: 42px;
    height: 42px;
    border-radius: 10px;
    flex-shrink: 0;
}

.install-text {
    flex: 1;
    min-width: 0;
    display: flex;
    flex-direction: column;
    gap: 2px;
}

.install-text strong {
    font-size: 0.85rem;
    color: var(--text-primary);
}

.install-text span {
    font-size: 0.72rem;
    color: var(--text-secondary);
    line-height: 1.35;
}

.install-banner .btn-primary {
    padding: 8px 14px;
    font-size: 0.8rem;
    flex-shrink: 0;
}

.install-dismiss {
    background: transparent;
    border: none;
    color: var(--text-muted);
    cursor: pointer;
    font-size: 1rem;
    padding: 6px;
    flex-shrink: 0;
}

/* --- Feedback Modal --- */
.feedback-modal-content {
    max-width: 480px;
}

.feedback-sub {
    font-size: 0.88rem;
    color: var(--text-secondary);
    line-height: 1.5;
}

.feedback-form {
    display: flex;
    flex-direction: column;
    gap: 10px;
    margin-top: 4px;
}

.feedback-form textarea,
.feedback-form input {
    background: var(--input-bg);
    border: 1px solid var(--border-color);
    border-radius: 8px;
    color: var(--text-primary);
    font-family: var(--font-body);
    font-size: 0.88rem;
    padding: 10px 12px;
    outline: none;
    resize: vertical;
    transition: var(--transition-fast);
}

.feedback-form textarea:focus,
.feedback-form input:focus {
    border-color: rgba(139, 92, 246, 0.6);
}

.feedback-form .btn-primary {
    justify-content: center;
}

.feedback-form .btn-primary:disabled {
    opacity: 0.6;
    cursor: not-allowed;
}

.feedback-status {
    font-size: 0.8rem;
    color: var(--text-muted);
    min-height: 1.2em;
    text-align: center;
}

.feedback-status.success {
    color: var(--color-emerald);
}

.feedback-status.error {
    color: var(--color-rose);
}

/* --- About Page --- */
.plain-link {
    text-decoration: none;
    color: inherit;
}

.about-content {
    flex: 1;
    overflow-y: auto;
    background: var(--panel-bg);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius);
    padding: 36px 40px;
    line-height: 1.7;
}

.about-content h2 {
    font-family: var(--font-heading);
    font-size: 1.6rem;
    margin-bottom: 12px;
    background: var(--title-gradient);
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
}

.about-content h3 {
    font-family: var(--font-heading);
    font-size: 1.1rem;
    margin: 26px 0 8px 0;
    color: var(--color-purple);
    display: flex;
    align-items: center;
    gap: 8px;
}

.about-content p,
.about-content li {
    font-size: 0.92rem;
    color: var(--text-secondary);
}

.about-content ul {
    margin: 8px 0 8px 22px;
    display: flex;
    flex-direction: column;
    gap: 6px;
}

.about-content strong {
    color: var(--text-primary);
}

.about-content a {
    color: var(--color-purple);
    font-weight: 600;
}

.about-content code {
    background: var(--subtle-bg);
    border: 1px solid var(--border-color);
    border-radius: 4px;
    padding: 1px 6px;
    font-size: 0.82em;
}

.about-footer {
    margin-top: 32px;
    padding-top: 16px;
    border-top: 1px solid var(--border-color);
    font-size: 0.82rem;
    color: var(--text-muted);
}

@media (max-width: 768px) {
    .about-content {
        padding: 20px 18px;
    }
}

/* --- Scrollbar Customization --- */
::-webkit-scrollbar {
    width: 6px;
}
::-webkit-scrollbar-track {
    background: transparent;
}
::-webkit-scrollbar-thumb {
    background: var(--scrollbar-thumb);
    border-radius: 3px;
}
::-webkit-scrollbar-thumb:hover {
    background: var(--scrollbar-thumb-hover);
}

/* --- Animations --- */
@keyframes slideUp {
    from {
        opacity: 0;
        transform: translateY(12px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

@keyframes typing {
    from { opacity: 0.2; transform: translateY(0); }
    to { opacity: 1; transform: translateY(-4px); }
}

@keyframes popStar {
    0% { transform: scale(1); }
    50% { transform: scale(1.3); }
    100% { transform: scale(1); }
}

/* --- Responsive Breakpoints --- */
@media (max-width: 1024px) {
    .app-container {
        height: auto;
        min-height: 100vh;
        overflow-y: auto;
    }
    
    .search-layout {
        grid-template-columns: 1fr;
        height: auto;
    }
    
    .chat-container {
        height: 60vh;
    }
    
    .results-sidebar {
        height: 60vh;
    }
}

/* --- Mobile: streamlined, app-like layout --- */
@media (max-width: 768px) {
    .app-container {
        padding: 10px;
        /* Room for the fixed bottom nav */
        padding-bottom: 84px;
    }
    
    /* Compact single-row header; nav moves to bottom bar */
    .app-header {
        padding: 10px 14px;
        margin-bottom: 10px;
        flex-direction: row;
        justify-content: space-between;
        align-items: center;
        gap: 10px;
    }
    
    .app-nav {
        display: none;
    }
    
    .mobile-nav {
        display: flex;
    }
    
    .logo-icon {
        width: 36px;
        height: 36px;
        font-size: 1rem;
    }
    
    .logo-text h1 {
        font-size: 1.05rem;
    }
    
    /* Keep the byline visible on mobile, drop only the long descriptor */
    .logo-text .logo-sub {
        display: block;
        font-size: 0.65rem;
        white-space: nowrap;
    }
    
    .hide-mobile-inline {
        display: none;
    }
    
    .header-actions {
        gap: 5px;
    }
    
    .header-actions .hide-mobile {
        display: none;
    }
    
    .action-btn {
        width: 34px;
        height: 34px;
        font-size: 0.85rem;
    }
    
    .settings-dropdown {
        right: 0;
        left: auto;
        transform: none;
        max-width: calc(100vw - 40px);
    }
    
    /* Welcome: shorter, less text */
    .welcome-box {
        padding: 20px 16px;
        gap: 12px;
    }
    
    .welcome-box h2 {
        font-size: 1.3rem;
    }
    
    .welcome-desc {
        display: none;
    }
    
    .suggested-queries {
        margin-top: 4px;
    }
    
    .suggest-btn {
        font-size: 0.75rem;
        padding: 7px 12px;
    }
    
    /* Search bar: icon-only action buttons */
    .search-bar-container {
        padding: 10px;
    }
    
    .search-action-btn .btn-label {
        display: none;
    }
    
    .search-action-btn {
        padding: 12px 14px;
    }
    
    .search-action-btn i {
        font-size: 0.95rem;
    }
    
    .input-wrapper input {
        padding: 12px 8px 12px 38px;
        font-size: 16px; /* Prevents iOS auto-zoom on focus */
    }
    
    .chat-messages {
        padding: 14px;
        gap: 14px;
    }
    
    .message-wrapper {
        max-width: 95%;
    }
    
    .message-bubble {
        padding: 12px 14px;
        font-size: 0.88rem;
    }
    
    .results-list {
        padding: 12px;
    }
    
    /* Schedule: full-width day tabs, stacked filters */
    .schedule-header {
        padding: 16px;
        gap: 12px;
    }
    
    .schedule-header h2 {
        font-size: 1.2rem;
    }
    
    .schedule-header > p {
        display: none;
    }
    
    .schedule-filters {
        flex-direction: column;
        align-items: stretch;
    }
    
    .day-selector {
        width: 100%;
    }
    
    .day-btn {
        flex: 1;
        padding: 8px 6px;
    }
    
    .filter-controls {
        flex-direction: row;
    }
    
    .search-box {
        flex: 1;
    }
    
    .search-box input {
        width: 100%;
    }
    
    .sessions-wrapper {
        padding: 12px;
        gap: 10px;
    }
    
    /* Session accordions: icon-only export, tighter */
    .accordion-header {
        padding: 12px 14px;
        gap: 10px;
    }
    
    .accordion-title-block h3 {
        font-size: 0.9rem;
    }
    
    .btn-ics-export .btn-label {
        display: none;
    }
    
    .btn-ics-export {
        padding: 8px 10px;
    }
    
    .btn-ics-export i {
        font-size: 0.85rem;
    }
    
    .accordion-body {
        padding: 10px;
    }
    
    /* My Schedule */
    .starred-header {
        padding: 16px;
    }
    
    .starred-header h2 {
        font-size: 1.2rem;
    }
    
    .starred-header > p {
        display: none;
    }
    
    .starred-title-row {
        flex-direction: column;
        align-items: stretch;
        gap: 10px;
    }
    
    .starred-list {
        padding: 12px;
    }
    
    /* Modal: bottom sheet style */
    .modal {
        padding: 0;
        align-items: flex-end;
    }
    
    .modal-content {
        max-width: 100%;
        max-height: 92vh;
        border-radius: 20px 20px 0 0;
        border-left: none;
        border-right: none;
        border-bottom: none;
    }
    
    .modal-body {
        padding: 16px;
    }
    
    .modal-body h2 {
        font-size: 1.15rem;
    }
    
    .modal-metadata-grid {
        grid-template-columns: 1fr;
        gap: 8px;
    }
    
    .modal-footer {
        padding: 12px 16px calc(12px + env(safe-area-inset-bottom));
    }
    
    .modal-action-btn {
        flex: 1 1 45%;
    }
    
    .calendar-dropdown-container {
        flex: 1 1 45%;
        display: flex;
    }
    
    .calendar-dropdown-container .modal-action-btn {
        flex: 1;
    }
}