:root {
    --bg-primary: #0f0f1a;
    --bg-secondary: #1a1a2e;
    --bg-card: #16213e;
    --text-primary: #e8e8e8;
    --text-secondary: #a0a0a0;
    --accent: #00d4ff;
    --accent-glow: rgba(0, 212, 255, 0.3);
    --success: #00c853;
    --warning: #ffc107;
    --danger: #ff5252;
    --border-radius: 12px;
    --shadow: 0 8px 32px rgba(0, 0, 0, 0.3);
}

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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    background: linear-gradient(135deg, var(--bg-primary) 0%, var(--bg-secondary) 100%);
    color: var(--text-primary);
    min-height: 100vh;
    line-height: 1.6;
}

.container {
    max-width: 1400px;
    margin: 0 auto;
    padding: 30px 40px;
}

header {
    text-align: center;
    margin-bottom: 30px;
}

header h1 {
    font-size: 2.2rem;
    background: linear-gradient(135deg, var(--accent), #a855f7);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    margin-bottom: 8px;
}

.subtitle {
    color: var(--text-secondary);
    font-size: 1rem;
}

/* Two-column layout */
.main-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 20px;
    align-items: start;
}

.column {
    display: flex;
    flex-direction: column;
    gap: 20px;
}

.card {
    background: var(--bg-card);
    border-radius: var(--border-radius);
    padding: 20px;
    box-shadow: var(--shadow);
    border: 1px solid rgba(255, 255, 255, 0.05);
    transition: transform 0.2s, box-shadow 0.2s;
}

.card:hover {
    transform: translateY(-2px);
    box-shadow: 0 12px 40px rgba(0, 0, 0, 0.4);
}

.card h2 {
    color: var(--accent);
    margin-bottom: 12px;
    font-size: 1.2rem;
    display: flex;
    align-items: center;
    gap: 8px;
}

.card h3 {
    color: var(--text-primary);
    margin: 16px 0 8px;
    font-size: 1rem;
}

.card p {
    color: var(--text-secondary);
    margin-bottom: 10px;
    font-size: 0.95rem;
}

.card a {
    color: var(--accent);
    text-decoration: none;
}

.card a:hover {
    text-decoration: underline;
}

code {
    background: rgba(0, 212, 255, 0.1);
    color: var(--accent);
    padding: 2px 6px;
    border-radius: 4px;
    font-family: 'SF Mono', Monaco, 'Cascadia Code', monospace;
    font-size: 0.85em;
}

.example {
    background: var(--bg-secondary);
    padding: 12px;
    border-radius: 8px;
    margin: 10px 0;
    border-left: 3px solid var(--accent);
}

.example code.highlight {
    background: rgba(0, 212, 255, 0.2);
    padding: 3px 10px;
    font-size: 0.95rem;
}

/* Tool Section */
.tool-container {
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.input-row {
    display: flex;
    gap: 12px;
    align-items: flex-end;
}

.input-group {
    display: flex;
    flex-direction: column;
    gap: 4px;
    flex: 1;
}

.input-group label {
    color: var(--text-secondary);
    font-size: 0.85rem;
}

.input-group input {
    padding: 10px 12px;
    border: 1px solid rgba(255, 255, 255, 0.1);
    border-radius: 8px;
    background: var(--bg-secondary);
    color: var(--text-primary);
    font-size: 0.95rem;
    transition: border-color 0.2s, box-shadow 0.2s;
}

.input-group input:focus {
    outline: none;
    border-color: var(--accent);
    box-shadow: 0 0 0 3px var(--accent-glow);
}

#convert-btn {
    padding: 10px 20px;
    background: linear-gradient(135deg, var(--accent), #a855f7);
    border: none;
    border-radius: 8px;
    color: white;
    font-size: 0.95rem;
    font-weight: 600;
    cursor: pointer;
    transition: transform 0.2s, box-shadow 0.2s;
    white-space: nowrap;
}

#convert-btn:hover {
    transform: scale(1.02);
    box-shadow: 0 4px 20px var(--accent-glow);
}

.result {
    display: flex;
    align-items: center;
    gap: 10px;
    padding: 12px;
    background: var(--bg-secondary);
    border-radius: 8px;
    flex-wrap: wrap;
}

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

.result code {
    font-size: 1rem;
    flex: 1;
    word-break: break-all;
}

.copy-btn {
    padding: 6px 12px;
    background: rgba(255, 255, 255, 0.1);
    border: 1px solid rgba(255, 255, 255, 0.2);
    border-radius: 6px;
    color: var(--text-primary);
    cursor: pointer;
    transition: background 0.2s;
    font-size: 0.9rem;
}

.copy-btn:hover {
    background: rgba(255, 255, 255, 0.2);
}

/* Cert Info */
.cert-info {
    display: flex;
    flex-direction: column;
    gap: 10px;
}

.info-row {
    display: flex;
    align-items: center;
    gap: 10px;
    padding: 10px 12px;
    background: var(--bg-secondary);
    border-radius: 8px;
    font-size: 0.95rem;
}

.info-row .label {
    color: var(--text-secondary);
    min-width: 80px;
}

.info-row.warning {
    background: rgba(255, 193, 7, 0.1);
    border: 1px solid rgba(255, 193, 7, 0.3);
    color: var(--warning);
    font-size: 0.9rem;
}

.badge {
    display: inline-block;
    padding: 2px 8px;
    border-radius: 20px;
    font-size: 0.75rem;
    font-weight: 600;
    margin-left: 6px;
}

.badge.success {
    background: rgba(0, 200, 83, 0.2);
    color: var(--success);
}

.badge.warning {
    background: rgba(255, 193, 7, 0.2);
    color: var(--warning);
}

.badge.danger {
    background: rgba(255, 82, 82, 0.2);
    color: var(--danger);
}

/* Download */
.download-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 12px;
    margin-bottom: 16px;
}

.download-btn {
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 14px;
    background: var(--bg-secondary);
    border-radius: 10px;
    text-decoration: none;
    color: var(--text-primary);
    transition: transform 0.2s, background 0.2s;
    border: 1px solid rgba(255, 255, 255, 0.05);
}

.download-btn:hover {
    transform: translateY(-2px);
    background: rgba(0, 212, 255, 0.1);
    text-decoration: none;
}

.download-btn .icon {
    font-size: 1.5rem;
}

.download-btn .text {
    display: flex;
    flex-direction: column;
}

.download-btn .text strong {
    font-size: 0.95rem;
}

.download-btn .text small {
    color: var(--text-secondary);
    font-size: 0.8rem;
}

/* PEM Section */
.pem-section {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 12px;
}

.pem-group {
    display: flex;
    flex-direction: column;
    gap: 6px;
}

.pem-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    color: var(--text-secondary);
    font-size: 0.85rem;
}

.pem-group textarea {
    width: 100%;
    height: 182px;
    padding: 10px;
    background: var(--bg-secondary);
    border: 1px solid rgba(255, 255, 255, 0.1);
    border-radius: 8px;
    color: var(--text-primary);
    font-family: 'SF Mono', Monaco, monospace;
    font-size: 0.75rem;
    resize: vertical;
}

/* Footer */
footer {
    text-align: center;
    padding: 24px 20px;
    color: var(--text-secondary);
    font-size: 0.9rem;
}

footer a {
    color: var(--accent);
    text-decoration: none;
}

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

/* Toast */
.toast {
    position: fixed;
    bottom: 30px;
    left: 50%;
    transform: translateX(-50%);
    background: var(--success);
    color: white;
    padding: 10px 20px;
    border-radius: 8px;
    font-weight: 500;
    animation: fadeInUp 0.3s ease, fadeOut 0.3s ease 1.7s forwards;
    z-index: 1000;
}

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

    to {
        opacity: 1;
        transform: translateX(-50%) translateY(0);
    }
}

@keyframes fadeOut {
    to {
        opacity: 0;
    }
}

/* Responsive - fallback for smaller screens */
@media (max-width: 1000px) {
    .main-grid {
        grid-template-columns: 1fr;
    }

    .container {
        padding: 20px;
    }

    .pem-section {
        grid-template-columns: 1fr;
    }

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