:root {
    --primary-color: #2563EB; /* Deep Blue */
    --primary-hover: #1D4ED8;
    --primary-light: #EFF6FF;
    --secondary-color: #64748B;
    --secondary-hover: #475569;
    --secondary-light: #F1F5F9;
    --danger-color: #EF4444;
    --danger-hover: #DC2626;
    --success-color: #10B981;
    --success-light: #D1FAE5;
    --warning-color: #F59E0B;
    --warning-light: #FEF3C7;
    --background-color: #F8FAFC; /* Soft light background */
    --card-bg: #FFFFFF;
    --text-main: #1E293B;
    --text-muted: #64748B;
    --border-color: #E2E8F0;
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
    --radius-sm: 8px;
    --radius-md: 12px;
    --radius-lg: 18px;
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Inter', sans-serif;
}

body {
    background-color: var(--background-color);
    color: var(--text-main);
    display: flex;
    flex-direction: column;
    min-height: 100vh;
}

/* Header */
.header {
    background-color: var(--card-bg);
    padding: 1.25rem 2rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
    box-shadow: var(--shadow-sm);
    position: sticky;
    top: 0;
    z-index: 100;
}

.logo {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--primary-color);
}

.nav ul {
    list-style: none;
    display: flex;
    gap: 2.5rem;
}

.nav a {
    text-decoration: none;
    color: var(--text-muted);
    font-weight: 500;
    transition: color 0.2s ease;
}

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

.header-contact {
    display: flex;
    gap: 1.5rem;
}

.contact-link {
    text-decoration: none;
    color: var(--text-muted);
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-size: 0.9rem;
    font-weight: 500;
    transition: color 0.2s ease;
}

.contact-link:hover {
    color: var(--primary-color);
}

/* Main Content */
.main-content {
    flex: 1;
    display: flex;
    justify-content: center;
    align-items: flex-start;
    padding: 3rem 1rem;
}

.calculator-container {
    max-width: 800px;
    width: 100%;
    display: flex;
    flex-direction: column;
    gap: 2rem;
}

.card {
    background-color: var(--card-bg);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-lg);
    padding: 2.5rem;
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.card:hover {
    box-shadow: 0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 10px 10px -5px rgba(0, 0, 0, 0.04);
}

.card-header {
    margin-bottom: 1.5rem;
}

.card-header h2 {
    font-size: 1.75rem;
    color: var(--text-main);
    font-weight: 700;
    margin-bottom: 0.25rem;
}

.subtitle {
    color: var(--text-muted);
    font-size: 0.95rem;
}

.flex-between {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

/* Input Area */
.input-wrapper {
    margin-bottom: 1.5rem;
}

textarea {
    width: 100%;
    padding: 1.25rem;
    font-size: 1.1rem;
    color: var(--text-main);
    background-color: var(--background-color);
    border: 2px solid var(--border-color);
    border-radius: var(--radius-md);
    outline: none;
    resize: vertical;
    transition: all 0.3s ease;
    line-height: 1.5;
}

textarea:focus {
    border-color: var(--primary-color);
    background-color: white;
    box-shadow: 0 0 0 4px rgba(37, 99, 235, 0.1);
}

textarea::placeholder {
    color: #94A3B8;
}

.validation-message {
    color: var(--danger-color);
    font-size: 0.85rem;
    margin-top: 0.5rem;
    font-weight: 500;
    min-height: 20px;
}

/* Buttons */
.action-buttons {
    display: flex;
    gap: 1rem;
    flex-wrap: wrap;
}

.btn {
    padding: 0.875rem 1.5rem;
    border: none;
    border-radius: var(--radius-sm);
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    transition: all 0.2s cubic-bezier(0.4, 0, 0.2, 1);
}

.btn:active {
    transform: scale(0.96);
}

.btn-primary {
    background-color: var(--primary-color);
    color: white;
}
.btn-primary:hover {
    background-color: var(--primary-hover);
    box-shadow: 0 4px 12px rgba(37, 99, 235, 0.3);
}

.btn-secondary {
    background-color: var(--secondary-light);
    color: var(--text-main);
}
.btn-secondary:hover {
    background-color: #E2E8F0;
}

.btn-danger-outline {
    background-color: transparent;
    color: var(--danger-color);
    border: 1px solid var(--border-color);
}
.btn-danger-outline:hover {
    background-color: #FEF2F2;
    border-color: #FCA5A5;
}

.btn-icon {
    background-color: var(--secondary-light);
    color: var(--text-muted);
    padding: 0.5rem 1rem;
    font-size: 0.9rem;
}
.btn-icon:hover {
    background-color: var(--primary-light);
    color: var(--primary-color);
}

/* Results Section */
.result-card.hidden {
    display: none;
}

.result-card {
    animation: fadeInSlideUp 0.5s cubic-bezier(0.175, 0.885, 0.32, 1.275) forwards;
}

.stats-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 1.5rem;
    margin-bottom: 2rem;
}

.stat-box {
    background-color: var(--background-color);
    padding: 1.5rem;
    border-radius: var(--radius-md);
    border: 1px solid var(--border-color);
    display: flex;
    flex-direction: column;
    align-items: flex-start;
    gap: 0.5rem;
    transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.stat-box:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-md);
    border-color: transparent;
}

.stat-icon-wrapper {
    width: 40px;
    height: 40px;
    border-radius: var(--radius-sm);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.25rem;
    margin-bottom: 0.5rem;
}

.stat-icon-wrapper.blue { background-color: var(--primary-light); color: var(--primary-color); }
.stat-icon-wrapper.green { background-color: var(--success-light); color: var(--success-color); }
.stat-icon-wrapper.orange { background-color: var(--warning-light); color: var(--warning-color); }

.stat-label {
    font-size: 0.9rem;
    font-weight: 600;
    color: var(--text-muted);
}

.stat-value {
    font-size: 2.5rem;
    font-weight: 800;
    word-break: break-all;
    line-height: 1.1;
}

.text-primary { color: var(--primary-color); }
.text-success { color: var(--success-color); }
.text-warning { color: var(--warning-color); }

.divider {
    border: none;
    border-top: 1px solid var(--border-color);
    margin: 2rem 0;
}

/* Details Grid */
.details-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 1.5rem;
    margin-bottom: 2rem;
}

.detail-item {
    display: flex;
    flex-direction: column;
    gap: 0.25rem;
}

.detail-label {
    font-size: 0.85rem;
    color: var(--text-muted);
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.detail-value {
    font-size: 1.25rem;
    font-weight: 700;
    color: var(--text-main);
}

/* Sorted Array Display */
.sorted-section {
    display: flex;
    flex-direction: column;
    gap: 0.75rem;
}

.sorted-array {
    background-color: var(--background-color);
    padding: 1rem 1.25rem;
    border-radius: var(--radius-sm);
    border: 1px solid var(--border-color);
    font-family: monospace;
    font-size: 1.1rem;
    color: var(--text-main);
    word-break: break-all;
    max-height: 150px;
    overflow-y: auto;
}

/* Toast */
.toast {
    position: fixed;
    bottom: 2rem;
    right: 2rem;
    background-color: var(--text-main);
    color: white;
    padding: 1rem 1.5rem;
    border-radius: var(--radius-sm);
    display: flex;
    align-items: center;
    gap: 0.75rem;
    box-shadow: var(--shadow-lg);
    z-index: 1000;
    transition: all 0.4s cubic-bezier(0.68, -0.55, 0.265, 1.55);
    transform: translateY(150%);
    opacity: 0;
}
.toast.show {
    transform: translateY(0);
    opacity: 1;
}
.toast.success i { color: var(--success-color); }
.toast.danger i { color: var(--danger-color); }
.toast.info i { color: var(--primary-color); }

/* Footer */
.footer {
    background-color: var(--card-bg);
    padding: 2rem;
    text-align: center;
    border-top: 1px solid var(--border-color);
    margin-top: auto;
}
.text-danger { color: var(--danger-color); }
.footer-contact {
    display: flex;
    justify-content: center;
    gap: 2rem;
    font-size: 0.95rem;
    margin-top: 1rem;
}
.footer-contact a {
    color: var(--text-muted);
    text-decoration: none;
    transition: color 0.2s ease;
}
.footer-contact a:hover {
    color: var(--primary-color);
}

/* Animations */
@keyframes fadeInSlideUp {
    from { opacity: 0; transform: translateY(20px); }
    to { opacity: 1; transform: translateY(0); }
}