:root {
    /* Atmosphere Colors */
    --bg-deep: #05050a;
    --bg-gradient: radial-gradient(circle at top right, #1a1a2e, #05050a 70%);
    --accent: #00f2ff;
    --accent-glow: rgba(0, 242, 255, 0.5);
    --accent-secondary: #7000ff;
    
    /* Glassmorphism */
    --glass-bg: rgba(255, 255, 255, 0.05);
    --glass-border: rgba(255, 255, 255, 0.1);
    --glass-border-bright: rgba(255, 255, 255, 0.2);
    
    /* Text */
    --text-main: #f0f0f5;
    --text-dim: #a0a0b0;
    
    /* Highlight Colors (Accessibility) */
    --color-match: rgba(0, 255, 127, 0.15);
    --color-match-text: #00ff7f;
    --color-missing: rgba(255, 46, 99, 0.15);
    --color-missing-text: #ff2e63;
    --color-new: rgba(255, 211, 0, 0.15);
    --color-new-text: #ffd300;
}

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

body {
    font-family: 'Outfit', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
    background-color: var(--bg-deep);
    background-image: var(--bg-gradient);
    color: var(--text-main);
    line-height: 1.6;
    min-height: 100vh;
    overflow-x: hidden;
    padding-bottom: 4rem;
}

/* Background Atmosphere & Orbs */
.bg-atmosphere {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    z-index: -1;
    overflow: hidden;
}

.orb {
    position: absolute;
    border-radius: 50%;
    filter: blur(80px);
    opacity: 0.4;
    animation: drift 20s infinite alternate ease-in-out;
}

.orb-1 {
    width: 500px;
    height: 500px;
    background: radial-gradient(circle, var(--accent), transparent 70%);
    top: -100px;
    right: -100px;
}

.orb-2 {
    width: 400px;
    height: 400px;
    background: radial-gradient(circle, var(--accent-secondary), transparent 70%);
    bottom: -50px;
    left: -50px;
    animation-delay: -5s;
    animation-duration: 25s;
}

.orb-3 {
    width: 300px;
    height: 300px;
    background: radial-gradient(circle, #00ffcc, transparent 70%);
    top: 40%;
    left: 20%;
    animation-delay: -10s;
    animation-duration: 30s;
}

@keyframes drift {
    0% { transform: translate(0, 0) scale(1); }
    100% { transform: translate(50px, 100px) scale(1.1); }
}

/* Container */
.container {
    max-width: 1500px;
    margin: 0 auto;
    padding: 3rem 1rem;
    display: flex;
    flex-direction: column;
    position: relative;
    z-index: 1;
}

/* Header */
.app-header {
    text-align: center;
    margin-bottom: 3rem;
}

.app-header h1 {
    font-size: 3.5rem;
    font-weight: 700;
    letter-spacing: -1px;
    background: linear-gradient(to bottom, #fff, #a0a0b0);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    margin-bottom: 0.5rem;
}

.app-header p {
    color: var(--text-dim);
    font-size: 1.1rem;
    max-width: 600px;
    margin: 0 auto;
}

.hidden {
    display: none !important;
}

/* Glassmorphism Cards */
.glass-card {
    background: var(--glass-bg);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border: 1px solid var(--glass-border);
    border-top: 1px solid var(--glass-border-bright);
    border-left: 1px solid var(--glass-border-bright);
    border-radius: 24px;
    padding: 2rem;
    box-shadow: 0 8px 32px rgba(0, 0, 0, 0.4);
    transition: transform 0.4s cubic-bezier(0.175, 0.885, 0.32, 1.275), box-shadow 0.4s ease, border-color 0.4s ease;
}

.glass-card:hover {
    transform: translateY(-8px);
    box-shadow: 0 15px 45px rgba(0, 0, 0, 0.6);
    border-color: var(--glass-border-bright);
}

/* Upload Section */
.upload-section {
    display: flex;
    flex-wrap: wrap;
    gap: 2rem;
    margin-bottom: 3rem;
    transition: all 0.5s ease;
}

.upload-section.hidden {
    opacity: 0;
    transform: translateY(-20px);
    pointer-events: none;
    display: none !important;
}

.file-drop-area {
    flex: 1;
    min-width: 300px;
    transition: all 0.3s ease;
}

.upload-label {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    padding: 3.5rem 2rem;
    background: rgba(0, 0, 0, 0.2);
    border: 2px dashed var(--glass-border);
    border-radius: 20px;
    cursor: pointer;
    transition: all 0.4s cubic-bezier(0.175, 0.885, 0.32, 1.275);
    text-align: center;
    position: relative;
    overflow: hidden;
}

.file-drop-area:hover .upload-label {
    border-color: var(--accent);
    background: rgba(255, 255, 255, 0.05);
    transform: translateY(-5px);
}

.file-drop-area.drag-over .upload-label {
    background: rgba(0, 242, 255, 0.1);
    border-color: var(--accent);
    box-shadow: 0 0 30px var(--accent-glow);
    border-style: solid;
}

.upload-title {
    font-size: 1.2rem;
    font-weight: 700;
    color: var(--text-main);
    margin-bottom: 0.5rem;
    letter-spacing: 0.5px;
}

.upload-subtitle {
    font-size: 0.9rem;
    color: var(--text-dim);
    margin-bottom: 1.5rem;
}

.file-input {
    display: none;
}

.file-name-display {
    font-size: 0.85rem;
    font-weight: 700;
    color: var(--accent);
    background: rgba(0, 242, 255, 0.1);
    padding: 0.5rem 1.2rem;
    border-radius: 30px;
    border: 1px solid var(--accent-glow);
    max-width: 90%;
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
    box-shadow: 0 4px 10px rgba(0, 0, 0, 0.3);
}

/* Buttons */
.action-section {
    text-align: center;
    margin-bottom: 3rem;
}

.primary-btn {
    background: linear-gradient(135deg, var(--accent), var(--accent-secondary));
    color: white;
    border: none;
    padding: 1rem 3rem;
    font-size: 1.1rem;
    border-radius: 50px;
    cursor: pointer;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 1px;
    box-shadow: 0 4px 15px var(--accent-glow);
    transition: all 0.3s ease;
    position: relative;
    overflow: hidden;
}

.primary-btn:hover {
    transform: scale(1.05) translateY(-2px);
    box-shadow: 0 8px 25px var(--accent-glow);
    filter: brightness(1.1);
}

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

/* Toolbar - Fixed at top for persistent visibility */
.toolbar {
    position: fixed;
    top: 1.5rem;
    left: 50%;
    transform: translateX(-50%);
    z-index: 9999;
    display: flex;
    justify-content: center;
    align-items: center;
    padding: 0.8rem 2rem;
    background: rgba(0, 0, 0, 0.7);
    backdrop-filter: blur(30px);
    -webkit-backdrop-filter: blur(30px);
    border-radius: 60px;
    border: 1px solid var(--glass-border-bright);
    gap: 1.5rem;
    box-shadow: 0 15px 50px rgba(0,0,0,0.8);
    animation: toolbarAppear 0.5s cubic-bezier(0.175, 0.885, 0.32, 1.275);
}

@keyframes toolbarAppear {
    from { opacity: 0; transform: translate(-50%, -30px); }
    to { opacity: 1; transform: translate(-50%, 0); }
}

.secondary-btn {
    background: rgba(255, 255, 255, 0.05);
    color: white;
    border: 1px solid var(--glass-border);
    padding: 0.7rem 1.4rem;
    border-radius: 30px;
    cursor: pointer;
    font-size: 0.9rem;
    transition: all 0.3s ease;
    display: flex;
    align-items: center;
    gap: 0.6rem;
    font-weight: 600;
}

.secondary-btn:hover {
    background: rgba(255, 255, 255, 0.1);
    border-color: var(--accent);
    box-shadow: 0 0 15px var(--accent-glow);
    transform: translateY(-2px);
}

.secondary-btn.danger:hover {
    border-color: var(--color-missing-text);
    box-shadow: 0 0 15px rgba(255, 46, 99, 0.4);
    color: var(--color-missing-text);
}

.btn-icon {
    width: 18px;
    height: 18px;
    filter: invert(1);
}

/* Zoom Slider - CUSTOM STYLE */
.zoom-controls {
    display: flex;
    align-items: center;
    gap: 1rem;
    flex: 1;
}

.zoom-controls label {
    font-size: 0.8rem;
    font-weight: 700;
    text-transform: uppercase;
    color: var(--text-dim);
}

input[type="range"] {
    -webkit-appearance: none;
    width: 100%;
    height: 26px; /* Extra thick track as requested */
    background: rgba(255, 255, 255, 0.08);
    border-radius: 20px;
    outline: none;
    padding: 0 6px; /* Padding at the ends */
    border: 1px solid var(--glass-border);
    cursor: pointer;
    box-shadow: inset 0 2px 10px rgba(0, 0, 0, 0.5);
}

input[type="range"]::-webkit-slider-runnable-track {
    width: 100%;
    height: 26px;
    border-radius: 20px;
}

input[type="range"]::-webkit-slider-thumb {
    -webkit-appearance: none;
    width: 16px; /* Smaller than track */
    height: 16px; /* Smaller than track */
    background: white;
    border: none;
    border-radius: 50%;
    cursor: pointer;
    box-shadow: 0 0 15px var(--accent);
    margin-top: 5px; /* Center within the 26px track: (26-16)/2 */
    transition: transform 0.2s ease, background 0.2s ease;
}

input[type="range"]::-webkit-slider-thumb:hover {
    transform: scale(1.1);
    background: var(--accent);
}

#zoomVal {
    min-width: 45px;
    font-weight: 700;
    color: var(--accent);
}

/* Navigation Group */
.nav-group {
    display: flex;
    gap: 0.5rem;
    padding: 0 0.5rem;
    border-left: 1px solid var(--glass-border);
}

.change-info {
    font-size: 0.85rem;
    color: #fff;
    background: linear-gradient(135deg, var(--accent-secondary), #330066);
    padding: 0.4rem 1rem;
    border-radius: 20px;
    font-weight: 700;
    box-shadow: 0 4px 10px rgba(112, 0, 255, 0.3);
}

/* Results Grid */
.results-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 2rem;
}

.card-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1.5rem;
    border-bottom: 1px solid var(--glass-border);
    padding-bottom: 1rem;
}

.result-card h2 {
    font-size: 1.4rem;
    font-weight: 700;
    background: linear-gradient(to right, #fff, #a0a0b0);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.pdf-viewer {
    height: 75vh;
    overflow-y: auto;
    padding: 2rem;
    background: rgba(0, 0, 0, 0.5);
    border-radius: 16px;
    display: flex;
    flex-direction: column;
    gap: 2rem;
    align-items: center;
    box-shadow: inset 0 5px 20px rgba(0, 0, 0, 0.8);
}

.page-container {
    position: relative;
    box-shadow: 0 15px 45px rgba(0, 0, 0, 0.6);
    background: white;
    transition: transform 0.3s ease;
}

.page-container:hover {
    transform: scale(1.02);
}

canvas {
    display: block;
    max-width: 100%;
}

/* Text Layer Highlighting */
.textLayer {
    position: absolute;
    left: 0;
    top: 0;
    right: 0;
    bottom: 0;
    overflow: hidden;
    opacity: 1;
    line-height: 1.0;
}

.textLayer > span {
    color: transparent;
    position: absolute;
    white-space: pre;
    cursor: text;
    transform-origin: 0% 0%;
}

.textLayer span.match { background-color: var(--color-match); }
.textLayer span.missing { background-color: var(--color-missing); }
.textLayer span.new { background-color: var(--color-new); }

/* Strong Colorblind Mode */
body.colorblind-mode {
    --color-match: rgba(0, 210, 255, 0.4);
    --color-match-text: #00d2ff;
    --color-missing: rgba(255, 140, 0, 0.5);
    --color-missing-text: #ff8c00;
    --color-new: rgba(224, 0, 255, 0.5);
    --color-new-text: #e000ff;
}

body.colorblind-mode .textLayer span.missing { box-shadow: inset 0 0 0 2px var(--color-missing-text); }
body.colorblind-mode .textLayer span.new { box-shadow: inset 0 0 0 2px var(--color-new-text); }

/* Custom Scrollbar */
::-webkit-scrollbar {
    width: 10px;
}

::-webkit-scrollbar-track {
    background: rgba(0, 0, 0, 0.2);
}

::-webkit-scrollbar-thumb {
    background: rgba(255, 255, 255, 0.1);
    border-radius: 10px;
    border: 2px solid transparent;
    background-clip: padding-box;
}

::-webkit-scrollbar-thumb:hover {
    background: rgba(255, 255, 255, 0.2);
    background-clip: padding-box;
}

/* Responsive */
@media (max-width: 1024px) {
    .results-grid { grid-template-columns: 1fr; }
    .toolbar { flex-direction: column; border-radius: 24px; padding: 1.5rem; gap: 1rem; }
    .zoom-controls { width: 100%; }
}