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

html {
    scroll-behavior: smooth;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    background: #121212;
    color: #e0e0e0;
    line-height: 1.6;
}

#app {
    display: flex;
    flex-direction: column;
    min-height: 100vh;
}

/* Hero Section */
.hero {
    background: linear-gradient(135deg, #1a1a1a 0%, #0d3a3a 100%);
    padding: 80px 20px;
    text-align: center;
    flex-grow: 1;
    display: flex;
    align-items: center;
    justify-content: center;
}

.hero-content {
    max-width: 700px;
    margin: 0 auto;
}

.hero h1 {
    font-size: 3.5rem;
    font-weight: 700;
    margin-bottom: 20px;
    color: #ffffff;
    text-shadow: 0 2px 10px rgba(0, 229, 255, 0.3);
}

.hero-subtitle {
    font-size: 1.2rem;
    margin-bottom: 40px;
    color: #b0b0b0;
    line-height: 1.8;
}

.hero-form {
    display: flex;
    flex-direction: column;
    gap: 15px;
}

.email-field {
    padding: 12px 16px;
    border: 2px solid #00e5ff;
    border-radius: 6px;
    background: rgba(255, 255, 255, 0.05);
    color: #ffffff;
    font-size: 1rem;
    transition: all 0.3s ease;
}

.email-field:focus {
    outline: none;
    border-color: #00e5ff;
    box-shadow: 0 0 20px rgba(0, 229, 255, 0.4);
    background: rgba(0, 229, 255, 0.1);
}

.captcha-container {
    display: flex;
    justify-content: center;
    margin: 10px 0;
}

.submit-button {
    padding: 12px 24px;
    border: none;
    border-radius: 6px;
    background: #00e5ff;
    color: #121212;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
}

.submit-button:hover:not(:disabled) {
    background: #00d4e8;
    box-shadow: 0 0 20px rgba(0, 229, 255, 0.5);
}

.submit-button:disabled {
    opacity: 0.5;
    cursor: not-allowed;
}

/* Features Section */
.features {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 30px;
    padding: 80px 20px;
    max-width: 1200px;
    margin: 0 auto;
    width: 100%;
}

.feature-card {
    background: rgba(255, 255, 255, 0.05);
    border: 1px solid rgba(0, 229, 255, 0.2);
    border-radius: 8px;
    padding: 30px;
    transition: all 0.3s ease;
}

.feature-card:hover {
    border-color: #00e5ff;
    box-shadow: 0 0 20px rgba(0, 229, 255, 0.2);
}

.feature-card h3 {
    color: #00e5ff;
    margin-bottom: 15px;
    font-size: 1.3rem;
}

.feature-card p {
    color: #b0b0b0;
    line-height: 1.8;
}

/* Tool Section */
.tool {
    padding: 60px 20px;
    max-width: 1000px;
    margin: 0 auto;
    width: 100%;
}

.tool h2 {
    text-align: center;
    margin-bottom: 30px;
    font-size: 2rem;
    color: #ffffff;
}

.tool-wrapper {
    position: relative;
}

.references-textarea {
    width: 100%;
    height: 300px;
    padding: 16px;
    border: 2px solid #00e5ff;
    border-radius: 8px;
    background: rgba(255, 255, 255, 0.05);
    color: #ffffff;
    font-family: 'Courier New', monospace;
    font-size: 0.95rem;
    resize: vertical;
    transition: all 0.3s ease;
}

.references-textarea:focus {
    outline: none;
    border-color: #00e5ff;
    box-shadow: 0 0 20px rgba(0, 229, 255, 0.3);
    background: rgba(0, 229, 255, 0.05);
}

.reference-counter {
    margin-top: 12px;
    text-align: right;
    color: #00e5ff;
    font-size: 0.9rem;
}

/* Results Section */
.results-section {
    padding: 60px 20px;
    max-width: 1200px;
    margin: 0 auto;
    width: 100%;
}

.progress-container {
    margin-bottom: 40px;
}

.progress-bar {
    width: 100%;
    height: 8px;
    background: rgba(255, 255, 255, 0.1);
    border-radius: 4px;
    overflow: hidden;
    margin-bottom: 15px;
}

.progress-fill {
    height: 100%;
    background: #00e5ff;
    width: 0%;
    transition: width 0.3s ease;
}

#progress-text {
    text-align: center;
    color: #00e5ff;
    font-weight: 500;
}

.results-container h2 {
    margin-bottom: 30px;
    font-size: 2rem;
    color: #ffffff;
}

.results-table {
    width: 100%;
    border-collapse: collapse;
    margin-bottom: 30px;
}

.results-table thead {
    background: rgba(0, 229, 255, 0.1);
}

.results-table th {
    padding: 12px;
    text-align: left;
    color: #00e5ff;
    font-weight: 600;
}

.results-table td {
    padding: 12px;
    border-bottom: 1px solid rgba(255, 255, 255, 0.1);
    color: #e0e0e0;
}

.status-badge {
    display: inline-block;
    padding: 4px 12px;
    border-radius: 4px;
    font-size: 0.85rem;
    font-weight: 500;
}

.status-active {
    background: rgba(76, 175, 80, 0.2);
    color: #4caf50;
}

.status-invalid {
    background: rgba(244, 67, 54, 0.2);
    color: #f44336;
}

.status-not-found {
    background: rgba(255, 193, 7, 0.2);
    color: #ffc107;
}

.status-found-no-doi {
    background: rgba(33, 150, 243, 0.2);
    color: #2196f3;
}

.export-button {
    padding: 12px 24px;
    border: 2px solid #00e5ff;
    border-radius: 6px;
    background: transparent;
    color: #00e5ff;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
}

.export-button:hover {
    background: #00e5ff;
    color: #121212;
}

/* How It Works */
.how-it-works {
    padding: 80px 20px;
    background: rgba(255, 255, 255, 0.02);
    text-align: center;
}

.how-it-works h2 {
    margin-bottom: 50px;
    font-size: 2rem;
    color: #ffffff;
}

.process-flow {
    display: flex;
    align-items: center;
    justify-content: center;
    flex-wrap: wrap;
    gap: 20px;
    max-width: 900px;
    margin: 0 auto;
}

.step {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 10px;
}

.step-number {
    width: 50px;
    height: 50px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: #00e5ff;
    color: #121212;
    border-radius: 50%;
    font-size: 1.5rem;
    font-weight: 700;
}

.step h4 {
    color: #e0e0e0;
    font-size: 0.95rem;
}

.arrow {
    color: #00e5ff;
    font-size: 1.5rem;
    font-weight: bold;
}

@media (max-width: 600px) {
    .arrow {
        display: none;
    }

    .process-flow {
        flex-direction: column;
        gap: 10px;
    }

    .hero h1 {
        font-size: 2rem;
    }
}

/* Footer */
.footer {
    background: rgba(0, 0, 0, 0.5);
    border-top: 1px solid rgba(0, 229, 255, 0.2);
    padding: 40px 20px;
    text-align: center;
    color: #888;
    margin-top: auto;
}

.footer-links {
    margin: 15px 0;
}

.footer-links a {
    color: #00e5ff;
    text-decoration: none;
    transition: color 0.3s ease;
}

.footer-links a:hover {
    color: #00d4e8;
}

.footer-credit {
    font-size: 0.85rem;
    margin-top: 15px;
    color: #666;
}

/* Responsive */
@media (max-width: 768px) {
    .hero {
        padding: 40px 20px;
    }

    .hero h1 {
        font-size: 2.5rem;
    }

    .hero-subtitle {
        font-size: 1rem;
    }

    .tool {
        padding: 40px 20px;
    }

    .references-textarea {
        height: 200px;
    }

    .results-table {
        font-size: 0.9rem;
    }

    .results-table th,
    .results-table td {
        padding: 8px;
    }
}