/* Reset and Base Styles */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    /* Light theme colors */
    --bg-gradient-light: linear-gradient(135deg, #ff6b35 0%, #f7931e 50%, #ff8c42 100%);
    --text-light: #333;
    --calculator-bg-light: white;
    --input-bg-light: #f7fafc;
    --border-light: #e2e8f0;
    --text-muted-light: #718096;
    --result-bg-light: #f0fff4;
    --result-border-light: #9ae6b4;
    --result-text-light: #22543d;
    
    /* Dark theme colors */
    --bg-gradient-dark: linear-gradient(135deg, #0f0c29 0%, #302b63 50%, #24243e 100%);
    --text-dark: #e2e8f0;
    --calculator-bg-dark: #1a202c;
    --input-bg-dark: #2d3748;
    --border-dark: #4a5568;
    --text-muted-dark: #a0aec0;
    --result-bg-dark: #2d3748;
    --result-border-dark: #38a169;
    --result-text-dark: #9ae6b4;
}

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    line-height: 1.6;
    color: var(--text-light);
    background: var(--bg-gradient-light);
    min-height: 100vh;
    transition: all 0.3s ease;
}

body.dark-mode {
    color: var(--text-dark);
    background: var(--bg-gradient-dark);
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 20px;
}

/* Header */
.header {
    margin-bottom: 40px;
    color: white;
}

.header-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 20px;
}

.header-left {
    text-align: left;
}

.header h1 {
    font-size: 3rem;
    font-weight: 700;
    margin-bottom: 10px;
    text-shadow: 0 2px 4px rgba(0,0,0,0.3);
}

.header p {
    font-size: 1.2rem;
    opacity: 0.9;
    font-weight: 300;
}

.header-right {
    display: flex;
    align-items: center;
}

/* Theme Toggle */
.theme-toggle {
    background: rgba(255, 255, 255, 0.1);
    border: 2px solid rgba(255, 255, 255, 0.2);
    color: white;
    width: 50px;
    height: 50px;
    border-radius: 50%;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all 0.3s ease;
    backdrop-filter: blur(10px);
    position: relative;
    overflow: hidden;
}

.theme-toggle:hover {
    background: rgba(255, 255, 255, 0.2);
    border-color: rgba(255, 255, 255, 0.4);
    transform: scale(1.05);
}

.theme-toggle i {
    font-size: 1.2rem;
    transition: all 0.3s ease;
}

.theme-toggle .fa-sun {
    position: absolute;
    opacity: 0;
    transform: rotate(90deg);
}

.theme-toggle .fa-moon {
    opacity: 1;
    transform: rotate(0deg);
}

body.dark-mode .theme-toggle .fa-sun {
    opacity: 1;
    transform: rotate(0deg);
}

body.dark-mode .theme-toggle .fa-moon {
    opacity: 0;
    transform: rotate(-90deg);
}

/* Algorithm Selector */
.algorithm-selector {
    display: flex;
    justify-content: center;
    gap: 20px;
    margin-bottom: 40px;
    flex-wrap: wrap;
}

.algo-btn {
    background: rgba(255, 255, 255, 0.1);
    border: 2px solid rgba(255, 255, 255, 0.2);
    color: white;
    padding: 15px 25px;
    border-radius: 12px;
    cursor: pointer;
    font-size: 1rem;
    font-weight: 500;
    transition: all 0.3s ease;
    backdrop-filter: blur(10px);
    display: flex;
    align-items: center;
    gap: 10px;
}

.algo-btn:hover {
    background: rgba(255, 255, 255, 0.2);
    border-color: rgba(255, 255, 255, 0.4);
    transform: translateY(-2px);
}

.algo-btn.active {
    background: rgba(255, 255, 255, 0.25);
    border-color: rgba(255, 255, 255, 0.6);
    box-shadow: 0 4px 20px rgba(0,0,0,0.2);
}

/* Calculator Container */
.calculator {
    background: var(--calculator-bg-light);
    border-radius: 20px;
    padding: 40px;
    box-shadow: 0 20px 40px rgba(0,0,0,0.1);
    margin-bottom: 30px;
    display: none;
    transition: all 0.3s ease;
}

body.dark-mode .calculator {
    background: var(--calculator-bg-dark);
    box-shadow: 0 20px 40px rgba(0,0,0,0.3);
}

.calculator.active {
    display: block;
    animation: fadeIn 0.5s ease;
}

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(20px); }
    to { opacity: 1; transform: translateY(0); }
}

.calc-header {
    text-align: center;
    margin-bottom: 40px;
}

.calc-header h2 {
    font-size: 2.5rem;
    color: var(--text-light);
    margin-bottom: 10px;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 15px;
    transition: color 0.3s ease;
}

.calc-header p {
    color: var(--text-muted-light);
    font-size: 1.1rem;
    transition: color 0.3s ease;
}

body.dark-mode .calc-header h2 {
    color: var(--text-dark);
}

body.dark-mode .calc-header p {
    color: var(--text-muted-dark);
}

/* Input Sections */
.input-section {
    margin-bottom: 40px;
}

.input-section h3 {
    font-size: 1.5rem;
    color: var(--text-light);
    margin-bottom: 15px;
    border-bottom: 2px solid var(--border-light);
    padding-bottom: 10px;
    transition: all 0.3s ease;
}

.input-section p {
    color: var(--text-muted-light);
    margin-bottom: 20px;
    transition: color 0.3s ease;
}

body.dark-mode .input-section h3 {
    color: var(--text-dark);
    border-bottom-color: var(--border-dark);
}

body.dark-mode .input-section p {
    color: var(--text-muted-dark);
}

/* Vertex Inputs */
.vertex-inputs {
    background: var(--input-bg-light);
    border-radius: 12px;
    padding: 25px;
    margin-bottom: 25px;
    transition: background-color 0.3s ease;
}

body.dark-mode .vertex-inputs {
    background: var(--input-bg-dark);
}

.vertex-controls {
    display: flex;
    gap: 15px;
    margin-bottom: 20px;
    flex-wrap: wrap;
}

.vertex-input {
    display: flex;
    align-items: center;
    gap: 15px;
    margin-bottom: 15px;
    padding: 15px;
    background: var(--calculator-bg-light);
    border-radius: 8px;
    border: 1px solid var(--border-light);
    transition: all 0.3s ease;
}

.vertex-input label {
    font-weight: 500;
    color: var(--text-light);
    min-width: 80px;
    transition: color 0.3s ease;
}

.vertex-input input {
    padding: 10px 15px;
    border: 1px solid var(--border-light);
    border-radius: 6px;
    font-size: 1rem;
    width: 100px;
    background: var(--calculator-bg-light);
    color: var(--text-light);
    transition: all 0.3s ease;
}

.vertex-input input:focus {
    outline: none;
    border-color: #667eea;
    box-shadow: 0 0 0 3px rgba(102, 126, 234, 0.1);
}

body.dark-mode .vertex-input {
    background: var(--calculator-bg-dark);
    border-color: var(--border-dark);
}

body.dark-mode .vertex-input label {
    color: var(--text-dark);
}

body.dark-mode .vertex-input input {
    background: var(--calculator-bg-dark);
    color: var(--text-dark);
    border-color: var(--border-dark);
}

/* Graph Inputs */
.graph-inputs {
    background: var(--input-bg-light);
    border-radius: 12px;
    padding: 25px;
    margin-bottom: 25px;
    transition: background-color 0.3s ease;
}

body.dark-mode .graph-inputs {
    background: var(--input-bg-dark);
}

.input-group {
    margin-bottom: 25px;
}

.input-group label {
    display: block;
    font-weight: 500;
    color: var(--text-light);
    margin-bottom: 8px;
    transition: color 0.3s ease;
}

.input-group input {
    padding: 12px 15px;
    border: 1px solid var(--border-light);
    border-radius: 6px;
    font-size: 1rem;
    width: 200px;
    background: var(--calculator-bg-light);
    color: var(--text-light);
    transition: all 0.3s ease;
}

.input-group input:focus {
    outline: none;
    border-color: #667eea;
    box-shadow: 0 0 0 3px rgba(102, 126, 234, 0.1);
}

body.dark-mode .input-group label {
    color: var(--text-dark);
}

body.dark-mode .input-group input {
    background: var(--calculator-bg-dark);
    color: var(--text-dark);
    border-color: var(--border-dark);
}

.edge-inputs h4 {
    font-size: 1.2rem;
    color: var(--text-light);
    margin-bottom: 10px;
    transition: color 0.3s ease;
}

.edge-inputs p {
    color: var(--text-muted-light);
    margin-bottom: 20px;
    font-size: 0.95rem;
    transition: color 0.3s ease;
}

body.dark-mode .edge-inputs h4 {
    color: var(--text-dark);
}

body.dark-mode .edge-inputs p {
    color: var(--text-muted-dark);
}

.edge-input {
    display: flex;
    align-items: center;
    gap: 15px;
    margin-bottom: 15px;
    padding: 15px;
    background: var(--calculator-bg-light);
    border-radius: 8px;
    border: 1px solid var(--border-light);
    transition: all 0.3s ease;
}

.edge-input label {
    font-weight: 500;
    color: var(--text-light);
    min-width: 100px;
    transition: color 0.3s ease;
}

.edge-input input {
    padding: 10px 15px;
    border: 1px solid var(--border-light);
    border-radius: 6px;
    font-size: 1rem;
    width: 120px;
    background: var(--calculator-bg-light);
    color: var(--text-light);
    transition: all 0.3s ease;
}

.edge-input input:focus {
    outline: none;
    border-color: #667eea;
    box-shadow: 0 0 0 3px rgba(102, 126, 234, 0.1);
}

body.dark-mode .edge-input {
    background: var(--calculator-bg-dark);
    border-color: var(--border-dark);
}

body.dark-mode .edge-input label {
    color: var(--text-dark);
}

body.dark-mode .edge-input input {
    background: var(--calculator-bg-dark);
    color: var(--text-dark);
    border-color: var(--border-dark);
}

/* Buttons */
.btn {
    padding: 12px 24px;
    border: none;
    border-radius: 8px;
    font-size: 1rem;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.3s ease;
    display: inline-flex;
    align-items: center;
    gap: 8px;
    text-decoration: none;
}

.btn-primary {
    background: linear-gradient(135deg, #ff6b35 0%, #f7931e 100%);
    color: white;
    box-shadow: 0 4px 15px rgba(255, 107, 53, 0.4);
    transition: all 0.3s ease;
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(255, 107, 53, 0.6);
}

body.dark-mode .btn-primary {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    box-shadow: 0 4px 15px rgba(102, 126, 234, 0.4);
}

body.dark-mode .btn-primary:hover {
    box-shadow: 0 6px 20px rgba(102, 126, 234, 0.6);
}

.btn-secondary {
    background: #e2e8f0;
    color: #4a5568;
}

.btn-secondary:hover {
    background: #cbd5e0;
    transform: translateY(-1px);
}

/* Results Section */
.result-section {
    background: var(--result-bg-light);
    border: 1px solid var(--result-border-light);
    border-radius: 12px;
    padding: 25px;
    margin-top: 30px;
    transition: all 0.3s ease;
}

body.dark-mode .result-section {
    background: var(--result-bg-dark);
    border-color: var(--result-border-dark);
}

.result-section.hidden {
    display: none;
}

.result-section h3 {
    color: var(--result-text-light);
    margin-bottom: 20px;
    font-size: 1.3rem;
    transition: color 0.3s ease;
}

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

.result-item {
    display: flex;
    flex-direction: column;
    gap: 8px;
}

.result-item strong {
    color: var(--result-text-light);
    font-size: 1.1rem;
    transition: color 0.3s ease;
}

body.dark-mode .result-section h3 {
    color: var(--result-text-dark);
}

body.dark-mode .result-item strong {
    color: var(--result-text-dark);
}

.code-block {
    background: #2d3748;
    color: #e2e8f0;
    padding: 15px;
    border-radius: 8px;
    font-family: 'Monaco', 'Menlo', 'Ubuntu Mono', monospace;
    font-size: 0.9rem;
    line-height: 1.5;
    white-space: pre-wrap;
    overflow-x: auto;
}

/* Footer */
.footer {
    text-align: center;
    color: white;
    margin-top: 40px;
    padding: 20px;
    opacity: 0.8;
}

.footer a {
    color: white;
    text-decoration: none;
    transition: all 0.3s ease;
    font-weight: 500;
}

.footer a:hover {
    opacity: 1;
    text-decoration: underline;
}

/* Responsive Design */
@media (max-width: 768px) {
    .container {
        padding: 15px;
    }
    
    .header-content {
        flex-direction: column;
        text-align: center;
        gap: 15px;
    }
    
    .header-left {
        text-align: center;
    }
    
    .header h1 {
        font-size: 2rem;
    }
    
    .header p {
        font-size: 1rem;
    }
    
    .algorithm-selector {
        flex-direction: column;
        align-items: center;
    }
    
    .algo-btn {
        width: 100%;
        max-width: 300px;
        justify-content: center;
    }
    
    .calculator {
        padding: 25px;
    }
    
    .calc-header h2 {
        font-size: 1.8rem;
        flex-direction: column;
        gap: 10px;
    }
    
    .vertex-input {
        flex-direction: column;
        align-items: flex-start;
        gap: 10px;
    }
    
    .vertex-input label {
        min-width: auto;
    }
    
    .vertex-input input {
        width: 100%;
    }
    
    .edge-input {
        flex-direction: column;
        align-items: flex-start;
        gap: 10px;
    }
    
    .edge-input label {
        min-width: auto;
    }
    
    .edge-input input {
        width: 100%;
    }
    
    .vertex-controls {
        flex-direction: column;
    }
    
    .btn {
        width: 100%;
        justify-content: center;
    }
}

@media (max-width: 480px) {
    .header h1 {
        font-size: 1.5rem;
    }
    
    .calculator {
        padding: 20px;
    }
    
    .calc-header h2 {
        font-size: 1.5rem;
    }
}