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

:root {
    --primary: #3b82f6;
    --primary-dark: #2563eb;
    --bg: #f8fafc;
    --card-bg: #ffffff;
    --text: #1e293b;
    --text-muted: #64748b;
    --border: #e2e8f0;
    --success: #10b981;
    --shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
}

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

.container {
    max-width: 800px;
    margin: 0 auto;
    padding: 20px;
}

/* Header */
header {
    text-align: center;
    padding: 30px 0;
}

header h1 {
    font-size: 2rem;
    margin-bottom: 8px;
}

.tagline {
    color: var(--text-muted);
    font-size: 1rem;
}

/* Tools Grid */
.tools-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(250px, 1fr));
    gap: 16px;
    margin: 20px 0;
}

.tool-card {
    background: var(--card-bg);
    border-radius: 12px;
    padding: 24px;
    text-decoration: none;
    color: var(--text);
    box-shadow: var(--shadow);
    transition: transform 0.2s, box-shadow 0.2s;
    border: 1px solid var(--border);
}

.tool-card:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 12px -3px rgba(0, 0, 0, 0.15);
}

.tool-icon {
    font-size: 2.5rem;
    display: block;
    margin-bottom: 12px;
}

.tool-card h2 {
    font-size: 1.2rem;
    margin-bottom: 8px;
}

.tool-card p {
    color: var(--text-muted);
    font-size: 0.9rem;
}

/* Tool Page */
.tool-page {
    background: var(--card-bg);
    border-radius: 12px;
    padding: 24px;
    box-shadow: var(--shadow);
    border: 1px solid var(--border);
}

.back-link {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    color: var(--primary);
    text-decoration: none;
    margin-bottom: 20px;
    font-weight: 500;
}

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

.tool-header {
    text-align: center;
    margin-bottom: 24px;
    padding-bottom: 20px;
    border-bottom: 1px solid var(--border);
}

.tool-header h1 {
    font-size: 1.5rem;
    margin-bottom: 8px;
}

.tool-header p {
    color: var(--text-muted);
}

/* Buttons */
.btn {
    background: var(--primary);
    color: white;
    border: none;
    padding: 12px 24px;
    border-radius: 8px;
    font-size: 1rem;
    font-weight: 500;
    cursor: pointer;
    transition: background 0.2s;
    display: inline-flex;
    align-items: center;
    gap: 8px;
}

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

.btn:active {
    transform: scale(0.98);
}

.btn-block {
    width: 100%;
    justify-content: center;
}

.btn-secondary {
    background: var(--text-muted);
}

.btn-secondary:hover {
    background: var(--text);
}

/* Result Display */
.result-box {
    background: var(--bg);
    border: 1px solid var(--border);
    border-radius: 8px;
    padding: 16px;
    margin: 16px 0;
}

.result-row {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 12px 0;
    border-bottom: 1px solid var(--border);
}

.result-row:last-child {
    border-bottom: none;
}

.result-label {
    color: var(--text-muted);
    font-size: 0.85rem;
    font-weight: 500;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.result-value {
    font-weight: 600;
    font-size: 1rem;
    display: flex;
    align-items: center;
    gap: 8px;
}

.copy-btn {
    background: transparent;
    border: 1px solid var(--border);
    border-radius: 6px;
    padding: 6px 10px;
    cursor: pointer;
    font-size: 0.8rem;
    color: var(--text-muted);
    transition: all 0.2s;
}

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

.copy-btn.copied {
    background: var(--success);
    color: white;
    border-color: var(--success);
}

/* Large Result Display */
.result-large {
    text-align: center;
    padding: 24px;
    background: var(--bg);
    border-radius: 8px;
    margin: 16px 0;
}

.result-large .value {
    font-size: 1.8rem;
    font-weight: 700;
    font-family: 'Monaco', 'Menlo', monospace;
    letter-spacing: 2px;
    margin-bottom: 12px;
    word-break: break-all;
}

/* Input Groups */
.input-group {
    margin-bottom: 16px;
}

.input-group label {
    display: block;
    margin-bottom: 6px;
    font-weight: 500;
    font-size: 0.9rem;
}

.input-group input,
.input-group select {
    width: 100%;
    padding: 12px;
    border: 1px solid var(--border);
    border-radius: 8px;
    font-size: 1rem;
    transition: border-color 0.2s;
}

.input-group input:focus,
.input-group select:focus {
    outline: none;
    border-color: var(--primary);
}

/* Section Divider */
.section-divider {
    display: flex;
    align-items: center;
    margin: 24px 0;
    color: var(--text-muted);
}

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

.section-divider span {
    padding: 0 16px;
    font-size: 0.85rem;
    text-transform: uppercase;
    letter-spacing: 1px;
}

/* Footer */
footer {
    text-align: center;
    padding: 30px 0;
    color: var(--text-muted);
    font-size: 0.9rem;
}

/* Toast notification */
.toast {
    position: fixed;
    bottom: 20px;
    left: 50%;
    transform: translateX(-50%) translateY(100px);
    background: var(--text);
    color: white;
    padding: 12px 24px;
    border-radius: 8px;
    font-size: 0.9rem;
    opacity: 0;
    transition: all 0.3s;
    z-index: 1000;
}

.toast.show {
    transform: translateX(-50%) translateY(0);
    opacity: 1;
}

/* Mobile adjustments */
@media (max-width: 480px) {
    .container {
        padding: 16px;
    }

    header h1 {
        font-size: 1.6rem;
    }

    .tool-page {
        padding: 16px;
    }

    .result-large .value {
        font-size: 1.4rem;
    }

    .result-row {
        flex-direction: column;
        align-items: flex-start;
        gap: 8px;
    }

    .result-value {
        width: 100%;
        justify-content: space-between;
    }
}