/* CSS Variables */
:root {
    --primary-color: #4f46e5;
    --primary-hover: #4338ca;
    --secondary-color: #0ea5e9;
    --success-color: #10b981;
    --warning-color: #f59e0b;
    --error-color: #ef4444;
    --bg-color: #f8fafc;
    --card-bg: #ffffff;
    --text-primary: #1e293b;
    --text-secondary: #64748b;
    --border-color: #e2e8f0;
    --highlight-bg: #fef08a;
    --highlight-border: #eab308;
    --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -2px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -4px rgba(0, 0, 0, 0.1);
    --radius-sm: 6px;
    --radius-md: 10px;
    --radius-lg: 16px;
    --transition: all 0.2s ease;
}

/* Reset & Base */
*, *::before, *::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

html {
    font-size: 16px;
    scroll-behavior: smooth;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, sans-serif;
    background: var(--bg-color);
    color: var(--text-primary);
    line-height: 1.6;
    min-height: 100vh;
}

/* Container */
.container {
    max-width: 900px;
    margin: 0 auto;
    padding: 2rem 1.5rem;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

/* Header */
header {
    text-align: center;
    margin-bottom: 2.5rem;
}

.logo-container {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 1rem;
    margin-bottom: 0.5rem;
}

.logo {
    width: 48px;
    height: 48px;
    object-fit: contain;
}

h1 {
    font-size: 2rem;
    font-weight: 700;
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.subtitle {
    color: var(--text-secondary);
    font-size: 1.1rem;
    margin-top: 0.5rem;
}

/* Main Content */
main {
    flex: 1;
    display: flex;
    flex-direction: column;
    gap: 2rem;
}

/* Sections */
section {
    background: var(--card-bg);
    border-radius: var(--radius-lg);
    padding: 1.75rem;
    box-shadow: var(--shadow-md);
    border: 1px solid var(--border-color);
}

section h2 {
    font-size: 1.1rem;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 1.25rem;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

/* Upload Section */
.upload-area {
    border: 2px dashed var(--border-color);
    border-radius: var(--radius-md);
    padding: 2.5rem 1.5rem;
    text-align: center;
    cursor: pointer;
    transition: var(--transition);
    background: var(--bg-color);
}

.upload-area:hover,
.upload-area.dragover {
    border-color: var(--primary-color);
    background: rgba(79, 70, 229, 0.05);
}

.upload-icon {
    font-size: 3rem;
    margin-bottom: 1rem;
}

.upload-area p {
    color: var(--text-secondary);
    margin-bottom: 0.25rem;
}

.supported-formats {
    font-size: 0.85rem;
    color: var(--text-secondary);
    opacity: 0.8;
}

.or-divider {
    display: flex;
    align-items: center;
    margin: 1.5rem 0;
    color: var(--text-secondary);
}

.or-divider::before,
.or-divider::after {
    content: '';
    flex: 1;
    height: 1px;
    background: var(--border-color);
}

.or-divider span {
    padding: 0 1rem;
    font-size: 0.875rem;
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.paste-area textarea {
    width: 100%;
    min-height: 150px;
    padding: 1rem;
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    font-family: inherit;
    font-size: 0.95rem;
    resize: vertical;
    transition: var(--transition);
}

.paste-area textarea:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(79, 70, 229, 0.1);
}

.document-info {
    display: flex;
    align-items: center;
    gap: 1rem;
    padding: 1rem;
    background: var(--bg-color);
    border-radius: var(--radius-md);
    margin-top: 1rem;
    flex-wrap: wrap;
}

.file-name {
    font-weight: 500;
    color: var(--primary-color);
}

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

.clear-btn {
    margin-left: auto;
    padding: 0.5rem 1rem;
    background: transparent;
    border: 1px solid var(--error-color);
    color: var(--error-color);
    border-radius: var(--radius-sm);
    cursor: pointer;
    font-size: 0.875rem;
    transition: var(--transition);
}

.clear-btn:hover {
    background: var(--error-color);
    color: white;
}

/* Keywords Section */
.keywords-input-container {
    display: flex;
    gap: 0.75rem;
}

.keywords-input-container input {
    flex: 1;
    padding: 0.75rem 1rem;
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    font-size: 1rem;
    transition: var(--transition);
}

.keywords-input-container input:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(79, 70, 229, 0.1);
}

.add-keyword-btn {
    padding: 0.75rem 1.5rem;
    background: var(--primary-color);
    color: white;
    border: none;
    border-radius: var(--radius-md);
    font-weight: 500;
    cursor: pointer;
    transition: var(--transition);
}

.add-keyword-btn:hover {
    background: var(--primary-hover);
}

.keywords-list {
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
    margin-top: 1rem;
    min-height: 2.5rem;
}

.keyword-tag {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.5rem 0.75rem;
    background: linear-gradient(135deg, rgba(79, 70, 229, 0.1), rgba(14, 165, 233, 0.1));
    border: 1px solid rgba(79, 70, 229, 0.3);
    border-radius: 50px;
    font-size: 0.9rem;
    animation: fadeIn 0.2s ease;
}

@keyframes fadeIn {
    from {
        opacity: 0;
        transform: scale(0.9);
    }
    to {
        opacity: 1;
        transform: scale(1);
    }
}

.keyword-tag .remove-keyword {
    background: none;
    border: none;
    color: var(--text-secondary);
    cursor: pointer;
    font-size: 1.1rem;
    line-height: 1;
    padding: 0;
    transition: var(--transition);
}

.keyword-tag .remove-keyword:hover {
    color: var(--error-color);
}

.keywords-hint {
    font-size: 0.85rem;
    color: var(--text-secondary);
    margin-top: 0.75rem;
}

/* Controls Section */
.control-group {
    margin-bottom: 1.5rem;
}

.control-group label {
    display: block;
    font-weight: 500;
    margin-bottom: 0.5rem;
}

.slider-container {
    display: flex;
    align-items: center;
    gap: 1rem;
}

.slider-container input[type="range"] {
    flex: 1;
    height: 6px;
    -webkit-appearance: none;
    appearance: none;
    background: var(--border-color);
    border-radius: 3px;
    cursor: pointer;
}

.slider-container input[type="range"]::-webkit-slider-thumb {
    -webkit-appearance: none;
    appearance: none;
    width: 20px;
    height: 20px;
    background: var(--primary-color);
    border-radius: 50%;
    cursor: pointer;
    transition: var(--transition);
}

.slider-container input[type="range"]::-webkit-slider-thumb:hover {
    transform: scale(1.1);
    box-shadow: 0 0 0 4px rgba(79, 70, 229, 0.2);
}

.slider-container span {
    min-width: 3rem;
    text-align: right;
    font-weight: 600;
    color: var(--primary-color);
}

.length-labels {
    display: flex;
    justify-content: space-between;
    font-size: 0.8rem;
    color: var(--text-secondary);
    margin-top: 0.25rem;
}

.summarize-btn {
    width: 100%;
    padding: 1rem 2rem;
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    color: white;
    border: none;
    border-radius: var(--radius-md);
    font-size: 1.1rem;
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition);
    margin-top: 0.5rem;
}

.summarize-btn:hover:not(:disabled) {
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

.summarize-btn:disabled {
    opacity: 0.5;
    cursor: not-allowed;
}

.summarize-btn .btn-loading {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
}

/* Results Section */
.results-section {
    animation: slideUp 0.3s ease;
}

@keyframes slideUp {
    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.results-stats {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 1rem;
    margin-bottom: 1.5rem;
}

.stat {
    text-align: center;
    padding: 1rem;
    background: var(--bg-color);
    border-radius: var(--radius-md);
}

.stat-value {
    display: block;
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--primary-color);
}

.stat-label {
    font-size: 0.8rem;
    color: var(--text-secondary);
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.summary-output {
    padding: 1.5rem;
    background: var(--bg-color);
    border-radius: var(--radius-md);
    border-left: 4px solid var(--primary-color);
    line-height: 1.8;
    font-size: 1rem;
}

.summary-output .highlight {
    background: var(--highlight-bg);
    padding: 0.1rem 0.3rem;
    border-radius: 3px;
    border-bottom: 2px solid var(--highlight-border);
    font-weight: 500;
}

.summary-output .sentence {
    display: block;
    margin-bottom: 0.75rem;
    padding-left: 1rem;
    border-left: 2px solid transparent;
    transition: var(--transition);
}

.summary-output .sentence:hover {
    border-left-color: var(--primary-color);
    background: rgba(79, 70, 229, 0.03);
}

.results-actions {
    display: flex;
    gap: 1rem;
    margin-top: 1.5rem;
}

.action-btn {
    flex: 1;
    padding: 0.75rem 1.5rem;
    background: var(--card-bg);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    cursor: pointer;
    font-size: 0.95rem;
    transition: var(--transition);
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
}

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

/* Footer */
footer {
    text-align: center;
    padding: 2rem 0 1rem;
    margin-top: auto;
    color: var(--text-secondary);
    font-size: 0.9rem;
}

footer a {
    color: var(--primary-color);
    text-decoration: none;
    font-weight: 500;
    transition: var(--transition);
}

footer a:hover {
    text-decoration: underline;
}

/* Mobile Responsive */
@media (max-width: 768px) {
    .container {
        padding: 1.5rem 1rem;
    }

    h1 {
        font-size: 1.5rem;
    }

    .subtitle {
        font-size: 1rem;
    }

    section {
        padding: 1.25rem;
    }

    .upload-area {
        padding: 2rem 1rem;
    }

    .upload-icon {
        font-size: 2.5rem;
    }

    .results-stats {
        grid-template-columns: repeat(2, 1fr);
    }

    .keywords-input-container {
        flex-direction: column;
    }

    .add-keyword-btn {
        width: 100%;
    }

    .results-actions {
        flex-direction: column;
    }

    .logo-container {
        flex-direction: column;
        gap: 0.5rem;
    }

    .logo {
        width: 40px;
        height: 40px;
    }
}

@media (max-width: 480px) {
    .container {
        padding: 1rem 0.75rem;
    }

    section {
        padding: 1rem;
        border-radius: var(--radius-md);
    }

    .stat-value {
        font-size: 1.25rem;
    }

    .stat-label {
        font-size: 0.7rem;
    }

    .document-info {
        flex-direction: column;
        align-items: flex-start;
    }

    .clear-btn {
        margin-left: 0;
        width: 100%;
    }
}

/* Utility Classes */
.hidden {
    display: none !important;
}

/* Toast Notification */
.toast {
    position: fixed;
    bottom: 2rem;
    left: 50%;
    transform: translateX(-50%);
    background: var(--text-primary);
    color: white;
    padding: 1rem 2rem;
    border-radius: var(--radius-md);
    box-shadow: var(--shadow-lg);
    z-index: 1000;
    animation: toastIn 0.3s ease;
}

@keyframes toastIn {
    from {
        opacity: 0;
        transform: translateX(-50%) translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateX(-50%) translateY(0);
    }
}

.toast.fade-out {
    animation: toastOut 0.3s ease forwards;
}

@keyframes toastOut {
    from {
        opacity: 1;
        transform: translateX(-50%) translateY(0);
    }
    to {
        opacity: 0;
        transform: translateX(-50%) translateY(20px);
    }
}