:root {
    /* Light Mode Tokens (Warm & Eye-Catching) */
    --bg-color: #fff4e6;
    --text-color: #431407;
    --card-bg: rgba(255, 255, 255, 0.85);
    --card-border: rgba(255, 255, 255, 0.7);
    --primary-color: #f97316;
    --primary-hover: #ea580c;
    --secondary-color: #f59e0b;
    --accent-color: #10b981;
    --danger-color: #ef4444;
    --navbar-bg: rgba(255, 255, 255, 0.85);
    --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.05);
    --shadow-md: 0 4px 6px -1px rgb(0 0 0 / 0.1), 0 2px 4px -2px rgb(0 0 0 / 0.1);
    --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.1), 0 4px 6px -4px rgb(0 0 0 / 0.1);
    --glass-blur: blur(16px);
    --border-radius: 16px;
    --hover-bg: #ffedd5;
    --input-bg: rgba(255, 255, 255, 0.9);
    --input-border: #fdba74;
    --text-muted: #9a3412;
    --bg-pattern: radial-gradient(#fed7aa 1.5px, transparent 1.5px);
}

[data-theme="dark"] {
    /* Dark Mode Tokens (Deep Grey & Warm Accents) */
    --bg-color: #121212;
    --text-color: #f3f4f6;
    --card-bg: rgba(30, 30, 30, 0.85);
    --card-border: rgba(255, 255, 255, 0.1);
    --primary-color: #f97316;
    --primary-hover: #ea580c;
    --secondary-color: #f59e0b;
    --accent-color: #10b981;
    --danger-color: #ef4444;
    --navbar-bg: rgba(18, 18, 18, 0.9);
    --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.5);
    --shadow-md: 0 4px 6px -1px rgb(0 0 0 / 0.4), 0 2px 4px -2px rgb(0 0 0 / 0.4);
    --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.5), 0 4px 6px -4px rgb(0 0 0 / 0.5);
    --hover-bg: #2a2a2a;
    --input-bg: rgba(30, 30, 30, 0.9);
    --input-border: #404040;
    --text-muted: #a3a3a3;
    --bg-pattern: radial-gradient(#404040 1px, transparent 1px);
}

/* Enable native view transitions for all same-origin navigations for Chrome 126+ */
@view-transition {
    navigation: auto;
}

@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(8px);
    }

    to {
        opacity: 1;
        transform: translateY(0);
    }
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    transition: background-color 0.3s ease, color 0.3s ease, border-color 0.3s ease, box-shadow 0.3s ease;
}

body {
    font-family: 'Inter', sans-serif;
    background-color: var(--bg-color);
    background-image: var(--bg-pattern);
    background-size: 24px 24px;
    color: var(--text-color);
    line-height: 1.6;
    animation: fadeIn 0.35s ease-out forwards;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

/* Typography */
h1,
h2,
h3,
h4 {
    font-weight: 700;
    color: var(--text-color);
    margin-bottom: 0.5rem;
}

/* Navbar */
.navbar {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1rem 2rem;
    position: sticky;
    top: 0;
    z-index: 100;
    background-color: var(--navbar-bg);
    backdrop-filter: var(--glass-blur);
    -webkit-backdrop-filter: var(--glass-blur);
    border-bottom: 1px solid var(--card-border);
    box-shadow: var(--shadow-sm);
}

.logo {
    font-size: 1.25rem;
    font-weight: 700;
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.nav-links {
    display: flex;
    gap: 1.5rem;
    align-items: center;
}

.nav-links a {
    text-decoration: none;
    color: var(--text-color);
    font-weight: 500;
    position: relative;
}

.nav-links a:hover {
    color: var(--primary-color);
}

.nav-links a:not(.btn-primary):not(.btn-secondary)::after {
    content: '';
    position: absolute;
    width: 0;
    height: 2px;
    bottom: -4px;
    left: 0;
    background-color: var(--primary-color);
    transition: width 0.3s ease;
}

.nav-links a:not(.btn-primary):not(.btn-secondary):hover::after,
.nav-links a.active:not(.btn-primary):not(.btn-secondary)::after {
    width: 100%;
}

.nav-links a.active:not(.btn-primary):not(.btn-secondary) {
    color: var(--primary-color) !important;
    background-color: var(--hover-bg);
    padding: 0.25rem 0.75rem;
    border-radius: 8px;
    font-weight: 600;
}

.nav-links .btn-primary.active {
    background-color: var(--accent-color) !important;
    color: white !important;
    box-shadow: 0 4px 14px 0 rgba(16, 185, 129, 0.4) !important;
}

.nav-links .btn-secondary.active {
    background-color: var(--accent-color) !important;
    border-color: var(--accent-color) !important;
    color: white !important;
}

.nav-controls {
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.mobile-menu-btn {
    background: none;
    border: none;
    color: var(--text-color);
    cursor: pointer;
    display: none;
    /* Hidden on desktop */
    align-items: center;
    justify-content: center;
    padding: 0.5rem;
    border-radius: 50%;
    transition: background-color 0.2s ease, transform 0.2s ease;
}

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

.mobile-menu-btn.active svg {
    transform: rotate(90deg);
    transition: transform 0.25s ease;
}

#theme-toggle {
    background: none;
    border: none;
    font-size: 1.5rem;
    cursor: pointer;
    padding: 0.5rem;
    border-radius: 50%;
    color: var(--text-color);
}

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

/* Buttons */
.btn-primary {
    background-color: var(--primary-color);
    color: white !important;
    padding: 0.5rem 1.25rem;
    border-radius: 9999px;
    border: none;
    cursor: pointer;
    font-weight: 600;
    text-align: center;
    box-shadow: 0 4px 14px 0 rgba(249, 115, 22, 0.39);
}

.btn-primary:hover {
    background-color: var(--primary-hover);
    transform: translateY(-1px);
    box-shadow: 0 6px 20px rgba(249, 115, 22, 0.5);
    color: white !important;
}

.btn-secondary {
    background-color: transparent;
    color: var(--primary-color);
    border: 2px solid var(--primary-color);
    padding: 0.4rem 1rem;
    border-radius: 9999px;
    cursor: pointer;
    font-weight: 600;
}

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

.btn-accent {
    background-color: var(--accent-color);
    color: white;
    padding: 0.4rem 1rem;
    border-radius: 9999px;
    border: none;
    cursor: pointer;
    font-weight: 600;
    text-decoration: none;
    display: inline-block;
}

.btn-accent:hover {
    background-color: #059669;
    /* darker accent */
}

/* Container & Header */
.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 2rem;
    flex: 1;
    width: 100%;
}

.page-header {
    display: flex;
    flex-wrap: wrap;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 2rem;
    gap: 1rem;
}

.center-header {
    justify-content: center;
    flex-direction: column;
    text-align: center;
}

.center-header p {
    color: var(--text-muted);
    font-size: 1.1rem;
}

.search-bar {
    position: relative;
    max-width: 400px;
    width: 100%;
}

.search-bar input {
    width: 100%;
    padding: 0.75rem 3rem 0.75rem 1.5rem;
    border-radius: 9999px;
    border: 1px solid var(--input-border);
    background-color: var(--input-bg);
    color: var(--text-color);
    font-size: 1rem;
    outline: none;
    box-shadow: var(--shadow-sm);
}

.search-bar input:focus {
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(99, 102, 241, 0.2);
}

.search-icon {
    position: absolute;
    right: 1.25rem;
    top: 50%;
    transform: translateY(-50%);
    color: var(--text-muted);
    font-size: 1.1rem;
}

.btn-delete:hover {
    color: var(--danger-color) !important;
    transform: scale(1.1);
}

/* Breadcrumbs */
.breadcrumbs {
    width: 100%;
    display: flex;
    gap: 0.5rem;
    font-size: 0.9rem;
    color: var(--text-muted);
    margin-top: 1rem;
}

.breadcrumb-link {
    color: var(--primary-color);
    text-decoration: none;
    cursor: pointer;
    font-weight: 500;
}

.breadcrumb-link:hover {
    text-decoration: underline;
}

/* Grid Layouts */
.grid-container {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
    gap: 1.5rem;
}

/* Cards */
.card {
    background-color: var(--card-bg);
    backdrop-filter: var(--glass-blur);
    -webkit-backdrop-filter: var(--glass-blur);
    border: 1px solid var(--card-border);
    border-radius: var(--border-radius);
    padding: 1.5rem;
    box-shadow: var(--shadow-md);
    cursor: pointer;
    display: flex;
    flex-direction: column;
    gap: 1rem;
    position: relative;
    overflow: hidden;
}

.card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-lg);
    border-color: var(--primary-color);
}

.card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 4px;
    background: linear-gradient(90deg, var(--primary-color), var(--secondary-color));
    opacity: 0;
    transition: opacity 0.3s ease;
}

.card:hover::before {
    opacity: 1;
}

.card-icon {
    font-size: 2.5rem;
    margin-bottom: 0.5rem;
}

.card-title {
    font-size: 1.25rem;
    font-weight: 600;
}

.card-meta {
    font-size: 0.875rem;
    color: var(--text-muted);
    margin-top: auto;
}

/* Note Card specific */
.note-actions {
    display: flex;
    gap: 0.5rem;
    margin-top: 1rem;
}

/* Upload Section */
.upload-section {
    max-width: 600px;
    margin: 0 auto;
}

.form-group {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
    margin-bottom: 1.5rem;
    text-align: left;
}

.form-row {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 1rem;
}

label {
    font-weight: 500;
    color: var(--text-color);
}

input[type="text"],
select {
    padding: 0.75rem;
    border-radius: 0.5rem;
    border: 1px solid var(--input-border);
    background-color: var(--input-bg);
    color: var(--text-color);
    font-family: inherit;
    font-size: 1rem;
    outline: none;
}

input[type="text"]:focus,
select:focus {
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(99, 102, 241, 0.2);
}

/* File Upload Zone */
.file-upload-label {
    cursor: pointer;
}

.file-upload-zone {
    border: 2px dashed var(--input-border);
    border-radius: var(--border-radius);
    padding: 2rem;
    text-align: center;
    background-color: rgba(0, 0, 0, 0.02);
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 1rem;
    transition: border-color 0.3s ease, background-color 0.3s ease;
}

.file-upload-zone:hover,
.file-upload-zone.dragover {
    border-color: var(--primary-color);
    background-color: rgba(99, 102, 241, 0.05);
}

.upload-icon {
    font-size: 3rem;
    color: var(--primary-color);
}

.hidden-input {
    display: none;
}

.w-100 {
    width: 100%;
}

.status-msg {
    margin-top: 1rem;
    padding: 1rem;
    border-radius: 0.5rem;
    text-align: center;
    font-weight: 500;
}

.status-msg.success {
    background-color: rgba(16, 185, 129, 0.1);
    color: var(--accent-color);
    border: 1px solid var(--accent-color);
}

.status-msg.error {
    background-color: rgba(239, 68, 68, 0.1);
    color: var(--danger-color);
    border: 1px solid var(--danger-color);
}

.hidden {
    display: none !important;
}

/* PDF Modal */
.modal {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0, 0, 0, 0.75);
    backdrop-filter: blur(5px);
    z-index: 1000;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 2rem;
    opacity: 1;
    transition: opacity 0.3s ease;
}

.modal.hidden {
    opacity: 0;
    pointer-events: none;
}

.modal-content {
    background-color: var(--card-bg);
    backdrop-filter: var(--glass-blur);
    -webkit-backdrop-filter: var(--glass-blur);
    width: 100%;
    max-width: 600px;
    height: auto;
    border-radius: var(--border-radius);
    display: flex;
    flex-direction: column;
    overflow: hidden;
    box-shadow: var(--shadow-lg);
    border: 1px solid var(--card-border);
}

/* Specific styling for PDF Viewer Modal */
#pdf-modal .modal-content {
    max-width: 1400px;
    width: 100%;
    height: 100%;
    background-color: var(--bg-color);
    /* solid bg for pdf */
    border-radius: 12px;
}

#pdf-modal .modal-header {
    background: linear-gradient(to right, var(--primary-color), var(--secondary-color));
    border-bottom: none;
    padding: 1rem 1.5rem;
}

#pdf-modal #pdf-modal-title {
    color: white;
    margin-bottom: 0;
    font-size: 1.25rem;
    font-weight: 600;
}

#pdf-modal .btn-close {
    color: white;
    background-color: rgba(255, 255, 255, 0.2);
}

#pdf-modal .btn-close:hover {
    background-color: rgba(255, 255, 255, 0.4);
    color: white;
    transform: scale(1.1);
}

.modal-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1.25rem 1.5rem;
    border-bottom: 1px solid var(--card-border);
}

.btn-close {
    background: none;
    border: none;
    font-size: 1.25rem;
    color: var(--text-muted);
    cursor: pointer;
    border-radius: 50%;
    width: 36px;
    height: 36px;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all 0.2s ease;
}

.btn-close:hover {
    background-color: var(--danger-color);
    color: white;
}

.modal-body {
    flex: 1;
    background-color: #f3f4f6;
    /* subtle background behind the iframe */
    position: relative;
    padding: 0;
    overflow: hidden;
    display: flex;
    /* prevents iframe margin issues */
}

/* Dark mode adjustment for iframe wrapper */
[data-theme="dark"] .modal-body {
    background-color: #1e1e1e;
}

.modal-body iframe {
    width: 100%;
    height: 100%;
    border: none;
    display: block;
    flex-grow: 1;
}

/* Responsive */
@media (max-width: 768px) {
    .form-row {
        grid-template-columns: 1fr;
    }

    h1,
    .card-title {
        font-size: 1.25rem;
    }

    h2 {
        font-size: 1.15rem;
    }

    .navbar {
        padding: 1rem;
        flex-direction: row;
        justify-content: space-between;
        align-items: center;
        gap: 0;
        flex-wrap: wrap;
    }

    .mobile-menu-btn {
        display: flex !important;
    }

    .nav-links {
        display: none;
        gap: 0.5rem;
        flex-direction: column;
        align-items: stretch;
        width: 100%;
        order: 3;
        /* Push below logo and controls */
        padding-bottom: 0.5rem;
        animation: fadeIn 0.2s ease-out forwards;
    }

    .nav-links.active {
        display: flex;
    }

    .nav-links a {
        text-align: center;
        width: 100%;
        display: block;
        padding: 0.75rem 1rem;
        border-radius: 8px;
    }

    .nav-links a:hover {
        background-color: var(--hover-bg);
    }

    .btn-secondary {
        width: 100%;
        display: block;
        margin-top: 0;
        text-align: center;
    }

    .container {
        padding: 1rem;
    }

    .page-header {
        flex-direction: column;
        align-items: flex-start;
        gap: 1rem;
    }

    .search-bar {
        max-width: 100%;
        width: 100%;
    }

    .breadcrumbs {
        flex-wrap: wrap;
        margin-top: 0.5rem;
    }

    .grid-container {
        grid-template-columns: 1fr;
    }

    .modal {
        padding: 0;
    }

    .modal-content {
        height: 100vh;
        border-radius: 0;
        max-width: 100%;
    }

    #pdf-modal .modal-content {
        border-radius: 0;
        width: 100vw;
        height: 100vh;
        max-width: 100%;
    }
}

@media (max-width: 480px) {
    .nav-links {
        flex-direction: column;
        width: 100%;
    }

    .nav-links a {
        width: 100%;
        text-align: center;
        padding: 0.75rem;
    }

    .btn-secondary {
        width: 100%;
    }

    .card {
        padding: 1.25rem;
    }
}