:root {
    --bg-primary: #0d1117;
    --bg-secondary: #161b22;
    --text-primary: #c9d1d9;
    --text-secondary: #8b949e;
    --accent: #0ac5c5;
    --accent-hover: #3ddbd9;
    --accent-light: #0ac5c5;
    --highlight: #0ac5c5;
    --highlight-dark: #3ddbd9;
    --teal: #0ac5c5;
    --purple: #0ac5c5;
    --card-bg: #161b22;
    --gradient-start: #0ac5c5;
    --gradient-mid: #3ddbd9;
    --gradient-end: #0ac5c5;
    --spacing: 1rem;
    --border-radius: 12px;
    --transition: all 0.3s ease;
    --shadow: 0 10px 30px rgba(10, 197, 197, 0.15);
    --shadow-light: 0 5px 15px rgba(10, 197, 197, 0.1);
    --success: #3fb950;
    --error: #f85149;
}

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

body {
    font-family: 'Inter', sans-serif;
    background-color: var(--bg-primary);
    color: var(--text-primary);
    line-height: 1.6;
    background-image: 
        radial-gradient(circle at 5% 10%, rgba(10, 197, 197, 0.05) 0%, transparent 20%),
        radial-gradient(circle at 95% 5%, rgba(10, 197, 197, 0.05) 0%, transparent 20%),
        radial-gradient(circle at 50% 90%, rgba(10, 197, 197, 0.05) 0%, transparent 20%);
}

.container {
    width: 100%;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--spacing);
}

/* Header & Navigation */
header {
    background-color: rgba(22, 27, 34, 0.95);
    box-shadow: 0 2px 20px rgba(0, 0, 0, 0.2);
    position: sticky;
    top: 0;
    z-index: 100;
    backdrop-filter: blur(10px);
    border-bottom: 1px solid rgba(240, 246, 252, 0.1);
}

nav {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1.2rem 0;
}

.logo {
    font-weight: 700;
    font-size: 1.8rem;
    color: var(--text-primary);
    text-decoration: none;
    display: flex;
    align-items: center;
    font-family: 'Poppins', sans-serif;
}

.logo span {
    background: linear-gradient(90deg, var(--accent), var(--accent-hover));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    position: relative;
}

.logo span::after {
    content: '';
    position: absolute;
    bottom: -2px;
    left: 0;
    width: 100%;
    height: 3px;
    background: linear-gradient(90deg, var(--accent), var(--accent-hover));
    border-radius: 2px;
}

.nav-links {
    display: flex;
    list-style: none;
}

.nav-links li {
    margin-left: 2rem;
}

.nav-links a {
    text-decoration: none;
    color: var(--text-primary);
    font-weight: 500;
    transition: var(--transition);
    position: relative;
    padding: 0.5rem 0;
}

.nav-links a::after {
    content: '';
    position: absolute;
    bottom: -5px;
    left: 0;
    width: 0;
    height: 2px;
    background: linear-gradient(90deg, var(--accent), var(--accent-hover));
    transition: var(--transition);
}

.nav-links a:hover::after {
    width: 100%;
}

.nav-links a:hover {
    color: var(--accent);
}

.hamburger {
    display: none;
    cursor: pointer;
    font-size: 1.5rem;
    color: var(--text-primary);
}

/* Hero Section */
.hero {
    padding: 5rem 0 3.5rem;
    text-align: center;
    position: relative;
    overflow: hidden;
}

.hero::before {
    content: '';
    position: absolute;
    top: -200px;
    right: -100px;
    width: 500px;
    height: 500px;
    background: linear-gradient(135deg, var(--accent) 0%, var(--accent-hover) 100%);
    opacity: 0.05;
    border-radius: 50%;
    z-index: -1;
}

.hero::after {
    content: '';
    position: absolute;
    bottom: -150px;
    left: -100px;
    width: 400px;
    height: 400px;
    background: linear-gradient(135deg, var(--teal) 0%, var(--accent-light) 100%);
    opacity: 0.05;
    border-radius: 50%;
    z-index: -1;
}

.hero h1 {
    font-size: 3rem;
    margin-bottom: 1.5rem;
    font-weight: 700;
    font-family: 'Poppins', sans-serif;
    background: linear-gradient(90deg, var(--accent), var(--accent-hover));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.hero p {
    font-size: 1.2rem;
    color: var(--text-secondary);
    max-width: 700px;
    margin: 0 auto 3rem;
}

/* URL Shortener Form */
.shortener-form {
    background: var(--card-bg);
    padding: 2.5rem;
    border-radius: var(--border-radius);
    box-shadow: var(--shadow);
    max-width: 800px;
    margin: 0 auto;
    position: relative;
    z-index: 2;
    border: 1px solid rgba(240, 246, 252, 0.1);
}

.form-group {
    display: flex;
    gap: 1rem;
    margin-bottom: 1.5rem;
}

input[type="url"], input[type="text"], input[type="password"], input[type="number"] {
    flex: 1;
    padding: 1.2rem 1.5rem;
    border: 2px solid rgba(10, 197, 197, 0.3);
    border-radius: var(--border-radius);
    font-size: 1rem;
    font-family: inherit;
    transition: var(--transition);
    background: rgba(10, 197, 197, 0.03);
    color: var(--text-primary);
}

input[type="url"]:focus, input[type="text"]:focus, input[type="password"]:focus, input[type="number"]:focus {
    outline: none;
    border-color: var(--accent);
    box-shadow: 0 0 0 3px rgba(10, 197, 197, 0.2);
    background: var(--bg-secondary);
}

input[type="url"]::placeholder, input[type="text"]::placeholder, input[type="password"]::placeholder, input[type="number"]::placeholder {
    color: var(--text-secondary);
}

button {
    background: linear-gradient(90deg, var(--accent), var(--accent-hover));
    color: var(--bg-primary);
    border: none;
    border-radius: var(--border-radius);
    padding: 1.2rem 2rem;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition);
    box-shadow: var(--shadow-light);
}

button:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 20px rgba(10, 197, 197, 0.3);
    background: linear-gradient(90deg, var(--accent-hover), var(--accent-hover));
}

.advanced-options {
    margin-bottom: 1.5rem;
    padding: 1rem;
    background: rgba(10, 197, 197, 0.05);
    border-radius: var(--border-radius);
    border: 1px solid rgba(10, 197, 197, 0.1);
}

.advanced-options-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    cursor: pointer;
    margin-bottom: 0.5rem;
}

.advanced-options-content {
    display: none;
    grid-template-columns: 1fr 1fr;
    gap: 1rem;
}

.advanced-options-content.active {
    display: grid;
}

.option-group {
    margin-bottom: 1rem;
}

.option-group label {
    display: block;
    margin-bottom: 0.5rem;
    font-weight: 500;
    color: var(--text-primary);
}

.checkbox-group {
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.checkbox-group input[type="checkbox"] {
    width: 18px;
    height: 18px;
}

.result {
    display: none;
    margin-top: 1.5rem;
    padding: 1.5rem;
    background: linear-gradient(90deg, rgba(10, 197, 197, 0.08), rgba(10, 197, 197, 0.05));
    border-radius: var(--border-radius);
    border-left: 4px solid var(--success);
    align-items: center;
    justify-content: space-between;
    animation: fadeIn 0.5s ease;
}

.result.error {
    border-left: 4px solid var(--error);
    background: linear-gradient(90deg, rgba(248, 81, 73, 0.08), rgba(248, 81, 73, 0.05));
}

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(-10px); }
    to { opacity: 1; transform: translateY(0); }
}

.result.active {
    display: flex;
}

.short-url {
    color: var(--accent);
    font-weight: 500;
    text-decoration: none;
    font-size: 1.1rem;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.short-url i {
    font-size: 1.2rem;
}

.short-url:hover {
    text-decoration: underline;
    color: var(--accent-hover);
}

.copy-btn, .preview-btn {
    background: var(--accent);
    color: var(--bg-primary);
    padding: 0.8rem 1.5rem;
    font-size: 1rem;
    box-shadow: none;
    margin-left: 0.5rem;
}

.copy-btn:hover, .preview-btn:hover {
    background: var(--accent-hover);
    transform: translateY(-2px);
}

.qrcode-container {
    display: none;
    margin-top: 1.5rem;
    text-align: center;
    padding: 1rem;
    background: rgba(10, 197, 197, 0.05);
    border-radius: var(--border-radius);
    border: 1px solid rgba(10, 197, 197, 0.1);
}

.qrcode-container.active {
    display: block;
}

#qrcode {
    display: inline-block;
    padding: 10px;
    background: white;
    border-radius: 8px;
    margin-bottom: 1rem;
}

.qrcode-actions {
    display: flex;
    justify-content: center;
    gap: 1rem;
}

/* Features Section */
.features {
    padding: 5rem 0;
    background: var(--bg-secondary);
    position: relative;
}

.features::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 120px;
    background: linear-gradient(to bottom, var(--bg-primary), var(--bg-secondary));
    z-index: 1;
}

.section-title {
    text-align: center;
    font-size: 2.5rem;
    margin-bottom: 3.5rem;
    font-weight: 700;
    font-family: 'Poppins', sans-serif;
    position: relative;
    z-index: 2;
    background: linear-gradient(90deg, var(--accent), var(--accent-hover));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2.5rem;
    position: relative;
    z-index: 2;
}

.feature-card {
    background: var(--card-bg);
    padding: 2.2rem 1.8rem;
    border-radius: var(--border-radius);
    box-shadow: var(--shadow-light);
    text-align: center;
    transition: var(--transition);
    border-top: 4px solid transparent;
    border-image: linear-gradient(90deg, var(--accent), var(--accent-hover));
    border-image-slice: 1;
    border: 1px solid rgba(240, 246, 252, 0.1);
}

.feature-card:hover {
    transform: translateY(-8px);
    box-shadow: var(--shadow);
    border-color: rgba(10, 197, 197, 0.3);
}

.feature-icon {
    font-size: 2.8rem;
    margin-bottom: 1.2rem;
    background: linear-gradient(90deg, var(--accent), var(--accent-hover));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.feature-card h3 {
    margin-bottom: 1rem;
    font-weight: 600;
    font-size: 1.3rem;
    color: var(--accent);
}

.feature-card p {
    color: var(--text-secondary);
}

/* Footer */
footer {
    background: linear-gradient(90deg, #111827, #161b22);
    color: var(--text-primary);
    padding: 3rem 0 1.5rem;
    position: relative;
}

.footer-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
    gap: 2rem;
    margin-bottom: 2.5rem;
}

.footer-section h3 {
    font-size: 1.2rem;
    margin-bottom: 1.2rem;
    font-weight: 600;
    color: var(--text-primary);
}

.footer-links {
    list-style: none;
}

.footer-links li {
    margin-bottom: 0.8rem;
}

.footer-links a {
    text-decoration: none;
    color: var(--text-secondary);
    transition: var(--transition);
    display: inline-block;
    font-size: 0.95rem;
}

.footer-links a:hover {
    color: var(--accent);
    transform: translateX(5px);
}

.social-links {
    display: flex;
    gap: 0.8rem;
    margin-top: 1.2rem;
}

.social-links a {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 38px;
    height: 38px;
    background-color: rgba(201, 209, 217, 0.12);
    border-radius: 50%;
    color: var(--text-primary);
    transition: var(--transition);
}

.social-links a:hover {
    background-color: var(--accent);
    color: var(--bg-primary);
    transform: translateY(-3px);
}

.other-projects {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.project-link {
    color: var(--text-secondary);
    text-decoration: none;
    transition: var(--transition);
    display: inline-block;
    margin-bottom: 0.5rem;
    font-size: 0.95rem;
}

.project-link:hover {
    color: var(--accent);
    transform: translateX(5px);
}

.copyright {
    text-align: center;
    padding-top: 1.5rem;
    border-top: 1px solid rgba(201, 209, 217, 0.2);
    color: var(--text-secondary);
    font-size: 0.85rem;
}

/* Responsive Design */
@media (max-width: 768px) {
    .nav-links {
        display: none;
        flex-direction: column;
        position: absolute;
        top: 100%;
        left: 0;
        right: 0;
        background-color: var(--card-bg);
        box-shadow: 0 5px 10px rgba(0, 0, 0, 0.2);
        padding: 1.5rem;
        z-index: 100;
        border-top: 1px solid rgba(240, 246, 252, 0.1);
    }

    .nav-links.active {
        display: flex;
    }

    .nav-links li {
        margin: 1rem 0;
    }

    .hamburger {
        display: block;
    }

    .form-group {
        flex-direction: column;
    }

    .advanced-options-content {
        grid-template-columns: 1fr;
    }

    .hero h1 {
        font-size: 2.2rem;
    }

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

    .feature-card {
        padding: 1.8rem 1.3rem;
    }
    
    .footer-grid {
        grid-template-columns: 1fr;
        gap: 1.8rem;
    }

    .qrcode-actions {
        flex-direction: column;
        align-items: center;
    }
    
    .result {
        flex-direction: column;
        gap: 1rem;
        text-align: center;
    }
    
    .result-buttons {
        display: flex;
        gap: 0.5rem;
        flex-wrap: wrap;
        justify-content: center;
    }
}

/* Loading animation */
.loader {
    display: none;
    width: 24px;
    height: 24px;
    border: 3px solid rgba(10, 197, 197, 0.3);
    border-radius: 50%;
    border-top-color: var(--accent);
    animation: spin 1s ease-in-out infinite;
    margin: 0 auto;
}

@keyframes spin {
    to { transform: rotate(360deg); }
}

.loading .loader {
    display: block;
}

.loading .button-text {
    display: none;
}

/* URL validation styles */
.url-validation {
    margin-top: 0.5rem;
    font-size: 0.9rem;
    color: var(--error);
    display: none;
    text-align: left;
}

.url-validation.valid {
    color: var(--success);
}

/* Toast notification */
.toast {
    position: fixed;
    bottom: 20px;
    right: 20px;
    padding: 1rem 1.5rem;
    border-radius: var(--border-radius);
    background: var(--card-bg);
    color: var(--text-primary);
    box-shadow: var(--shadow);
    display: flex;
    align-items: center;
    gap: 0.8rem;
    z-index: 1000;
    transform: translateY(100px);
    opacity: 0;
    transition: all 0.3s ease;
    border-left: 4px solid var(--success);
}

.toast.error {
    border-left: 4px solid var(--error);
}

.toast.show {
    transform: translateY(0);
    opacity: 1;
}

.toast i {
    font-size: 1.2rem;
}

.toast.success i {
    color: var(--success);
}

.toast.error i {
    color: var(--error);
}