:root {
    --bg-color: #f8fafc;
    --text-color: #0f172a;
    --accent-color: #2563eb;
    --accent-hover: #1d4ed8;
    --success-color: #059669;
    --success-bg: #ecfdf5;
    --error-color: #dc2626;
    --error-bg: #fef2f2;
    --subtitle-color: #475569;
    --icon-color: #64748b;

    --mesh-1: hsla(215, 98%, 90%, 1);
    --mesh-2: hsla(205, 90%, 85%, 1);
    --mesh-3: hsla(230, 85%, 92%, 1);
    --mesh-4: hsla(220, 95%, 95%, 1);
    --mesh-5: hsla(210, 80%, 98%, 1);

    --card-bg: rgba(255, 255, 255, 0.7);
    --card-border: rgba(226, 232, 240, 0.8);
    --card-hover-bg: rgba(255, 255, 255, 0.85);
    --card-hover-border: #93c5fd;
    --inner-border: rgba(255, 255, 255, 0.6);
    --inner-border-hover: rgba(255, 255, 255, 0.9);
    --shield-bg: rgba(255, 255, 255, 0.7);
    --shield-border: rgba(255, 255, 255, 0.8);
    --shimmer-color: rgba(255, 255, 255, 0.8);

    --font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    --font-heading: 'Outfit', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
}

[data-theme="dark"] {
    --bg-color: #0f172a;
    --text-color: #f8fafc;
    --accent-color: #3b82f6;
    --accent-hover: #60a5fa;
    --success-color: #10b981;
    --success-bg: rgba(5, 150, 105, 0.15);
    --error-color: #ef4444;
    --error-bg: rgba(220, 38, 38, 0.15);
    --subtitle-color: #94a3b8;
    --icon-color: #94a3b8;

    --mesh-1: hsla(220, 50%, 15%, 1);
    --mesh-2: hsla(230, 40%, 12%, 1);
    --mesh-3: hsla(210, 60%, 10%, 1);
    --mesh-4: hsla(215, 45%, 18%, 1);
    --mesh-5: hsla(225, 55%, 14%, 1);

    --card-bg: rgba(30, 41, 59, 0.7);
    --card-border: rgba(51, 65, 85, 0.8);
    --card-hover-bg: rgba(30, 41, 59, 0.85);
    --card-hover-border: #3b82f6;
    --inner-border: rgba(255, 255, 255, 0.05);
    --inner-border-hover: rgba(255, 255, 255, 0.1);
    --shield-bg: rgba(30, 41, 59, 0.7);
    --shield-border: rgba(51, 65, 85, 0.8);
    --shimmer-color: rgba(255, 255, 255, 0.1);
}

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

body {
    font-family: var(--font-family);
    background-color: var(--bg-color);
    /* Mesh gradient background - moving aurora effect */
    background-image:
        radial-gradient(at 40% 20%, var(--mesh-1) 0px, transparent 50%),
        radial-gradient(at 80% 0%, var(--mesh-2) 0px, transparent 50%),
        radial-gradient(at 0% 50%, var(--mesh-3) 0px, transparent 50%),
        radial-gradient(at 80% 100%, var(--mesh-4) 0px, transparent 50%),
        radial-gradient(at 0% 0%, var(--mesh-5) 0px, transparent 50%);
    background-size: 200% 200%;
    animation: meshpan 15s ease infinite alternate;
    will-change: background-position;
    color: var(--text-color);
    display: flex;
    flex-direction: column;
    min-height: 100vh;
    padding: 2rem;
    align-items: center;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

@keyframes meshpan {
    0% {
        background-position: 0% 50%;
    }

    50% {
        background-position: 100% 50%;
    }

    100% {
        background-position: 0% 50%;
    }
}

/* Respect user's motion preferences */
@media (prefers-reduced-motion: reduce) {
    body {
        animation: none;
    }
}

header {
    width: 100%;
    max-width: 42rem;
    margin-bottom: 2.5rem;
    text-align: center;
}

h1 {
    font-family: var(--font-heading);
    font-size: clamp(1.85rem, 5vw, 2.25rem);
    font-weight: 700;
    color: var(--text-color);
    margin-bottom: 0.75rem;
    letter-spacing: -0.025em;
}

p.subtitle {
    color: var(--subtitle-color);
    font-size: clamp(1rem, 2.5vw, 1.125rem);
    line-height: 1.75;
}

main {
    flex: 1;
    width: 100%;
    max-width: 42rem;
    display: flex;
    flex-direction: column;
    align-items: center;
}

.drop-zone {
    flex: 1;
    width: 100%;
    background-color: var(--card-bg);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border: 2px dashed var(--card-border);
    border-radius: 20px;
    box-shadow:
        0 10px 30px -5px rgba(0, 0, 0, 0.05),
        inset 0 0 0 1px var(--inner-border);
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    transition: all 0.3s cubic-bezier(0.16, 1, 0.3, 1);
    cursor: pointer;
    padding: 4rem 2rem;
    position: relative;
    overflow: hidden;
}

/* Premium Focus Rings */
.drop-zone:focus-visible,
.theme-toggle:focus-visible,
.about-toggle:focus-visible,
.modal-close:focus-visible {
    outline: none;
    box-shadow: 0 0 0 2px var(--bg-color), 0 0 0 4px var(--accent-color);
}

.drop-zone:focus-visible {
    border-color: var(--accent-color);
}

.drop-zone:hover {
    border-color: var(--card-hover-border);
    box-shadow:
        0 20px 40px -5px rgba(0, 0, 0, 0.08),
        inset 0 0 0 1px var(--inner-border-hover);
    background-color: var(--card-hover-bg);
    transform: translateY(-2px);
}

.drop-zone.dragover {
    background-color: var(--success-bg);
    border-color: var(--accent-color);
    transform: scale(1.02);
    box-shadow: 0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 8px 10px -6px rgba(0, 0, 0, 0.1);
}

.drop-zone.processing {
    cursor: wait;
    border-style: solid;
    border-color: transparent;
    box-shadow: 0 0 0 2px var(--accent-color);
    background-color: var(--card-bg);
    transform: scale(1);
    pointer-events: none;
}

.drop-zone.success {
    border-style: solid;
    border-color: var(--success-color);
    background-color: var(--success-bg);
    box-shadow: 0 0 0 1px var(--success-color);
}

.drop-zone.error {
    border-style: dashed;
    border-color: var(--error-color);
    background-color: var(--error-bg);
    animation: shake 0.5s cubic-bezier(.36, .07, .19, .97) both;
}

@keyframes shake {

    10%,
    90% {
        transform: translate3d(-1px, 0, 0);
    }

    20%,
    80% {
        transform: translate3d(2px, 0, 0);
    }

    30%,
    50%,
    70% {
        transform: translate3d(-4px, 0, 0);
    }

    40%,
    60% {
        transform: translate3d(4px, 0, 0);
    }
}

.icon {
    width: 56px;
    height: 56px;
    margin-bottom: 1.5rem;
    color: var(--icon-color);
    transition: all 0.3s cubic-bezier(0.16, 1, 0.3, 1);
}

.default-icon {
    animation: float 4s ease-in-out infinite;
}

@keyframes float {
    0% {
        transform: translateY(0px);
    }

    50% {
        transform: translateY(-6px);
    }

    100% {
        transform: translateY(0px);
    }
}

.drop-zone:hover .default-icon {
    color: var(--accent-color);
    animation: none;
    transform: translateY(-8px) scale(1.05);
}

.drop-zone.success .icon {
    color: var(--success-color);
    transform: translateY(0);
}

.drop-zone.error .icon {
    color: var(--error-color);
}

.status-text {
    font-family: var(--font-heading);
    font-size: 1.5rem;
    font-weight: 600;
    margin-bottom: 0.5rem;
    text-align: center;
}

.sub-status-text {
    color: var(--subtitle-color);
    font-size: 0.9375rem;
    line-height: 1.5;
    text-align: center;
    max-width: 380px;
}

input[type="file"] {
    display: none;
}

/* Modern pulsing document animation for processing state */
.processing-pulse {
    display: none;
    width: 56px;
    height: 56px;
    margin-bottom: 1.5rem;
    color: var(--accent-color);
    animation: pulse 2s cubic-bezier(0.4, 0, 0.6, 1) infinite;
}

@keyframes pulse {

    0%,
    100% {
        opacity: 1;
        transform: scale(1);
    }

    50% {
        opacity: .5;
        transform: scale(1.05);
    }
}

.shield-container {
    display: flex;
    justify-content: center;
    width: 100%;
}

.shield {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    margin-top: 2.5rem;
    color: var(--subtitle-color);
    font-size: 0.875rem;
    font-weight: 500;
    background: var(--shield-bg);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border: 1px solid var(--shield-border);
    box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.05);
    padding: 0.5rem 1rem;
    border-radius: 9999px;
    position: relative;
    overflow: hidden;
}

.shield::after {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 50%;
    height: 100%;
    background: linear-gradient(90deg, transparent, var(--shimmer-color), transparent);
    animation: shimmer 6s infinite;
}

@keyframes shimmer {
    0% {
        left: -100%;
    }

    20% {
        left: 200%;
    }

    100% {
        left: 200%;
    }
}

.shield svg {
    width: 18px;
    height: 18px;
    color: var(--accent-color);
}

/* --- Modal Backdrop --- */
.modal-backdrop {
    position: fixed;
    top: 0;
    left: 0;
    width: 100vw;
    height: 100vh;
    background: rgba(15, 23, 42, 0.4);
    backdrop-filter: blur(8px);
    -webkit-backdrop-filter: blur(8px);
    z-index: 999;
    display: flex;
    align-items: center;
    justify-content: center;
    opacity: 0;
    visibility: hidden;
    transition: opacity 0.3s ease, visibility 0.3s ease;
}

.modal-backdrop.open {
    opacity: 1;
    visibility: visible;
}

/* --- Modal Panel --- */
.about-panel {
    width: 90%;
    max-width: 36rem;
    background: var(--card-bg);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border: 1px solid var(--card-border);
    border-radius: 16px;
    box-shadow: 0 25px 50px -12px rgba(0, 0, 0, 0.25), inset 0 0 0 1px var(--inner-border);
    padding: 1.75rem;
    position: relative;
    transform: scale(0.95) translateY(20px);
    opacity: 0;
    transition: all 0.4s cubic-bezier(0.16, 1, 0.3, 1);
    max-height: 85vh;
    overflow-y: auto;
    scrollbar-width: thin;
    scrollbar-color: rgba(148, 163, 184, 0.4) transparent;
}

.about-panel::-webkit-scrollbar {
    width: 6px;
}

.about-panel::-webkit-scrollbar-track {
    background: transparent;
    margin: 12px 0;
}

.about-panel::-webkit-scrollbar-thumb {
    background: rgba(148, 163, 184, 0.4);
    border-radius: 9999px;
}

.about-panel::-webkit-scrollbar-thumb:hover {
    background: rgba(148, 163, 184, 0.6);
}

.modal-backdrop.open .about-panel {
    transform: scale(1) translateY(0);
    opacity: 1;
}

.modal-close {
    position: absolute;
    top: 1rem;
    right: 1rem;
    background: transparent;
    border: none;
    color: var(--icon-color);
    cursor: pointer;
    padding: 0.35rem;
    border-radius: 50%;
    transition: all 0.2s ease;
    display: flex;
    align-items: center;
    justify-content: center;
}

.modal-close:hover {
    color: var(--error-color);
    background: rgba(220, 38, 38, 0.1);
}

.modal-close svg {
    width: 20px;
    height: 20px;
}

.about-panel h2 {
    font-family: var(--font-heading);
    font-size: 1.25rem;
    font-weight: 700;
    color: var(--text-color);
    margin-bottom: 0.5rem;
    padding-right: 2rem;
}

.about-panel>.about-section:first-of-type p {
    font-size: 0.8125rem;
    line-height: 1.6;
    color: var(--subtitle-color);
    margin-bottom: 0;
}

.about-panel h3 {
    font-family: var(--font-heading);
    font-size: 0.9375rem;
    font-weight: 600;
    color: var(--text-color);
    margin-bottom: 0.4rem;
    display: flex;
    align-items: center;
    gap: 0.4rem;
}

.about-panel h3 svg {
    width: 16px;
    height: 16px;
    min-width: 16px;
    color: var(--accent-color);
}

.about-panel p,
.about-panel li {
    color: var(--subtitle-color);
    font-size: 0.8125rem;
    line-height: 1.6;
}

.about-panel ul {
    list-style: none;
    padding: 0;
    margin: 0;
}

.about-panel li {
    padding: 0.125rem 0;
    padding-left: 1rem;
    position: relative;
}

.about-panel li::before {
    content: '';
    position: absolute;
    left: 0;
    top: 0.55rem;
    width: 5px;
    height: 5px;
    border-radius: 50%;
    background: var(--accent-color);
}

/* Premium Bento Grid */
.about-grid {
    display: grid;
    grid-template-columns: 1.15fr 0.85fr;
    gap: 1.25rem;
}

.about-section {
    margin-bottom: 0.75rem;
    background: rgba(255, 255, 255, 0.03);
    padding: 1rem;
    border-radius: 12px;
    border: 1px solid transparent;
    transition: all 0.3s cubic-bezier(0.16, 1, 0.3, 1);
}

.about-section:hover {
    background: var(--card-hover-bg);
    border-color: var(--card-border);
    transform: translateY(-4px);
    box-shadow: 0 10px 20px -5px rgba(0, 0, 0, 0.1);
}

.about-section:last-child {
    margin-bottom: 0;
}

.tech-badge {
    display: inline-block;
    padding: 0.15rem 0.6rem;
    margin: 0.15rem;
    font-size: 0.6875rem;
    font-weight: 500;
    border-radius: 6px;
    background: var(--card-hover-bg);
    border: 1px solid var(--card-border);
    color: var(--text-color);
    transition: all 0.2s ease;
}

.tech-badge:hover {
    border-color: var(--accent-color);
    color: var(--accent-color);
}

/* --- Developer Credit --- */
.dev-credit {
    margin-top: 1.25rem;
    padding-top: 1rem;
    border-top: 1px solid var(--card-border);
    display: flex;
    align-items: center;
    gap: 1rem;
}

.dev-credit-qr {
    width: 72px;
    min-width: 72px;
    border-radius: 8px;
}

.dev-credit-qr img {
    width: 100%;
    height: auto;
    display: block;
    object-fit: contain;
}

.dev-credit-info {
    flex: 1;
}

.dev-credit-info strong {
    font-family: var(--font-heading);
    font-size: 1.1rem;
    font-weight: 700;
    color: var(--text-color);
    display: block;
    margin-bottom: 0.15rem;
}

.dev-credit-info span {
    font-size: 0.75rem;
    color: var(--subtitle-color);
    line-height: 1.5;
    display: block;
}

.dev-credit-info a {
    font-size: 0.6875rem;
    color: var(--accent-color);
    text-decoration: none;
    font-weight: 500;
    margin-top: 0.25rem;
    display: inline-block;
}

.dev-credit-info a:hover {
    text-decoration: underline;
}

/* --- Theme Toggle --- */
.theme-toggle {
    position: absolute;
    top: 1.5rem;
    right: 1.5rem;
    background: var(--card-bg);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border: 1px solid var(--card-border);
    color: var(--icon-color);
    width: 44px;
    height: 44px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    transition: all 0.3s cubic-bezier(0.16, 1, 0.3, 1);
    box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.05);
    z-index: 100;
}

.theme-toggle:hover {
    transform: rotate(15deg) scale(1.05);
    color: var(--accent-color);
    border-color: var(--card-hover-border);
    background: var(--card-hover-bg);
}

.theme-toggle svg {
    width: 22px;
    height: 22px;
    transition: transform 0.5s cubic-bezier(0.4, 0, 0.2, 1);
}

.theme-toggle .sun-icon {
    display: none;
}

[data-theme="dark"] .theme-toggle .moon-icon {
    display: none;
}

[data-theme="dark"] .theme-toggle .sun-icon {
    display: block;
}

/* --- About Toggle --- */
.about-toggle {
    position: fixed;
    bottom: 1.5rem;
    right: 1.5rem;
    background: var(--card-bg);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border: 1px solid var(--card-border);
    color: var(--icon-color);
    padding: 0.75rem 1.25rem;
    border-radius: 9999px;
    display: flex;
    align-items: center;
    gap: 0.5rem;
    cursor: pointer;
    transition: all 0.3s cubic-bezier(0.16, 1, 0.3, 1);
    box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.05);
    z-index: 100;
    font-size: 0.9rem;
    font-weight: 500;
}

.about-toggle:hover {
    transform: translateY(-2px) scale(1.02);
    color: var(--accent-color);
    border-color: var(--card-hover-border);
    background: var(--card-hover-bg);
}

.about-toggle svg {
    width: 20px;
    height: 20px;
}

/* --- Responsive Design --- */
@media (max-width: 600px) {
    body {
        padding: 1.25rem;
    }

    h1 {
        margin-bottom: 0.5rem;
    }

    .drop-zone {
        padding: 3rem 1.5rem;
    }

    .about-grid {
        grid-template-columns: 1fr;
        gap: 1rem;
    }

    .theme-toggle {
        top: 1rem;
        right: 1rem;
        width: 40px;
        height: 40px;
    }

    .about-toggle {
        bottom: 1rem;
        right: 1rem;
        padding: 0.6rem 1rem;
        font-size: 0.85rem;
    }
}

/* --- Margins --- */
.mt-4 {
    margin-top: 1rem;
}

.mt-2 {
    margin-top: 0.5rem;
}

/* --- Body State --- */
body.modal-open {
    overflow: hidden;
}

/* --- Display Toggles --- */
.hidden {
    display: none !important;
}

.processing-pulse.visible {
    display: block;
}