/* ===== CSS Variables & Reset ===== */
:root {
    --primary: #6366f1;
    --primary-dark: #4f46e5;
    --primary-light: #818cf8;
    --secondary: #0ea5e9;
    --success: #16a34a;
    --warning: #f59e0b;
    --danger: #dc2626;
    --dark: #1f2937;
    --white: #ffffff;
    --gray-50: #f9fafb;
    --gray-100: #f3f4f6;
    --gray-200: #e5e7eb;
    --gray-300: #d1d5db;
    --gray-400: #9ca3af;
    --gray-500: #6b7280;
    --gray-600: #4b5563;
    --gray-700: #374151;
    --r-phase: #dc2626;
    --y-phase: #ca8a04;
    --b-phase: #2563eb;
    --gradient-primary: linear-gradient(135deg, #6366f1 0%, #8b5cf6 100%);
    --gradient-header: linear-gradient(135deg, #4f46e5 0%, #7c3aed 100%);
    --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.08);
    --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 8px 30px rgba(0, 0, 0, 0.12);
    --radius-sm: 8px;
    --radius-md: 12px;
    --radius-lg: 20px;
    --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

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

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
    background: linear-gradient(135deg, var(--gray-100) 0%, var(--gray-200) 50%, var(--white) 100%);
    min-height: 100vh;
    color: var(--gray-700);
    line-height: 1.6;
}

/* ===== Container ===== */
.container {
    max-width: 600px;
    margin: 0 auto;
    padding: 20px;
    min-height: 100vh;
}

/* ===== Header ===== */
.header {
    text-align: center;
    padding: 30px 0;
    margin-bottom: 20px;
}

.logo {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 12px;
    margin-bottom: 10px;
}

.logo-icon {
    font-size: 2.5rem;
    animation: pulse 2s infinite;
}

@keyframes pulse {

    0%,
    100% {
        transform: scale(1);
    }

    50% {
        transform: scale(1.1);
    }
}

.header h1 {
    font-size: 1.8rem;
    font-weight: 700;
    background: var(--gradient-header);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.subtitle {
    color: var(--gray-500);
    font-size: 0.95rem;
    margin-top: 5px;
}

/* ===== Calculator Type Selector ===== */
.calc-type-selector {
    display: flex;
    gap: 12px;
    margin-bottom: 24px;
    background: var(--white);
    padding: 8px;
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-md);
    border: 1px solid var(--gray-200);
}

.calc-type-btn {
    flex: 1;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    padding: 14px 20px;
    border: none;
    border-radius: var(--radius-md);
    background: transparent;
    color: var(--gray-500);
    font-family: inherit;
    font-size: 0.95rem;
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition);
}

.calc-type-btn:hover {
    color: var(--gray-700);
    background: var(--gray-100);
}

.calc-type-btn.active {
    background: var(--gradient-primary);
    color: white;
    box-shadow: 0 4px 15px rgba(99, 102, 241, 0.35);
}

.btn-icon {
    font-size: 1.2rem;
}

/* ===== Calculator Sections ===== */
.calculator-section {
    display: none;
    animation: fadeIn 0.4s ease;
}

.calculator-section.active {
    display: block;
}

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

    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* ===== Card ===== */
.card {
    background: var(--white);
    border-radius: var(--radius-lg);
    padding: 28px;
    box-shadow: var(--shadow-lg);
    border: 1px solid var(--gray-200);
}

.card-header {
    text-align: center;
    margin-bottom: 24px;
}

.card-header h2 {
    font-size: 1.3rem;
    font-weight: 600;
    color: var(--gray-700);
}

/* ===== Form Elements ===== */
.select-wrapper {
    margin-bottom: 20px;
}

.field-label {
    display: block;
    font-size: 0.85rem;
    font-weight: 600;
    color: var(--gray-600);
    margin-bottom: 8px;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

select {
    width: 100%;
    padding: 14px 18px;
    border: 2px solid var(--gray-200);
    border-radius: var(--radius-md);
    background: var(--gray-50);
    color: var(--gray-700);
    font-family: inherit;
    font-size: 1rem;
    cursor: pointer;
    transition: var(--transition);
    appearance: none;
    background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='24' height='24' viewBox='0 0 24 24' fill='none' stroke='%236b7280' stroke-width='2' stroke-linecap='round' stroke-linejoin='round'%3E%3Cpolyline points='6 9 12 15 18 9'%3E%3C/polyline%3E%3C/svg%3E");
    background-repeat: no-repeat;
    background-position: right 12px center;
    background-size: 18px;
}

select:hover,
select:focus {
    border-color: var(--primary);
    outline: none;
    box-shadow: 0 0 0 3px rgba(99, 102, 241, 0.15);
    background-color: var(--white);
}

.form-grid {
    display: grid;
    gap: 16px;
    margin-bottom: 24px;
}

.input-group {
    width: 100%;
}

.input-group.full-width {
    margin-bottom: 20px;
}

input[type="number"] {
    width: 100%;
    padding: 14px 18px;
    border: 2px solid var(--gray-200);
    border-radius: var(--radius-md);
    background: var(--gray-50);
    color: var(--gray-700);
    font-family: inherit;
    font-size: 1rem;
    transition: var(--transition);
}

input[type="number"]::placeholder {
    color: var(--gray-400);
}

input[type="number"]:hover,
input[type="number"]:focus {
    border-color: var(--primary);
    outline: none;
    box-shadow: 0 0 0 3px rgba(99, 102, 241, 0.15);
    background-color: var(--white);
}

/* ===== Phase Info ===== */
.phase-info {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
    margin-bottom: 24px;
    justify-content: center;
}

.phase-badge {
    display: flex;
    align-items: center;
    gap: 8px;
    padding: 10px 16px;
    border-radius: var(--radius-sm);
    font-size: 0.9rem;
    font-weight: 500;
    background: var(--gray-100);
    border: 1px solid var(--gray-200);
    color: var(--gray-600);
}

.phase-dot {
    width: 10px;
    height: 10px;
    border-radius: 50%;
}

.r-phase .phase-dot {
    background: var(--r-phase);
    box-shadow: 0 0 8px rgba(220, 38, 38, 0.5);
}

.y-phase .phase-dot {
    background: var(--y-phase);
    box-shadow: 0 0 8px rgba(202, 138, 4, 0.5);
}

.b-phase .phase-dot {
    background: var(--b-phase);
    box-shadow: 0 0 8px rgba(37, 99, 235, 0.5);
}

/* ===== Calculate Button ===== */
.calculate-btn {
    width: 100%;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 10px;
    padding: 16px 24px;
    border: none;
    border-radius: var(--radius-md);
    background: var(--gradient-primary);
    color: white;
    font-family: inherit;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition);
    box-shadow: 0 4px 15px rgba(99, 102, 241, 0.3);
}

.calculate-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 25px rgba(99, 102, 241, 0.4);
}

.calculate-btn:active {
    transform: translateY(0);
}

.btn-arrow {
    font-size: 1.2rem;
    transition: var(--transition);
}

.calculate-btn:hover .btn-arrow {
    transform: translateX(4px);
}

/* ===== Result Box ===== */
.result-box {
    margin-top: 24px;
    padding: 0;
    border-radius: var(--radius-md);
    overflow: hidden;
    min-height: 0;
    transition: var(--transition);
}

.result-box:not(:empty) {
    padding: 20px;
    background: linear-gradient(135deg, rgba(22, 163, 74, 0.08), rgba(22, 163, 74, 0.03));
    border: 1px solid rgba(22, 163, 74, 0.25);
}

.result-box.error {
    background: linear-gradient(135deg, rgba(220, 38, 38, 0.08), rgba(220, 38, 38, 0.03));
    border: 1px solid rgba(220, 38, 38, 0.25);
}

.result-value {
    font-size: 1.4rem;
    font-weight: 700;
    color: var(--success);
    text-align: center;
}

.error-text {
    color: var(--danger);
    font-weight: 600;
    text-align: center;
}

/* ===== Phase Results ===== */
.phase-results {
    display: flex;
    flex-direction: column;
    gap: 16px;
}

.phase-result-card {
    padding: 16px;
    border-radius: var(--radius-sm);
    background: var(--gray-50);
    border-left: 4px solid;
}

.phase-result-card.r-phase {
    border-color: var(--r-phase);
}

.phase-result-card.y-phase {
    border-color: var(--y-phase);
}

.phase-result-card.b-phase {
    border-color: var(--b-phase);
}

.phase-result-title {
    font-size: 0.9rem;
    font-weight: 600;
    margin-bottom: 8px;
    display: flex;
    align-items: center;
    gap: 8px;
    color: var(--gray-700);
}

.phase-result-title .phase-dot {
    width: 8px;
    height: 8px;
}

.region-values {
    display: flex;
    gap: 12px;
    flex-wrap: wrap;
}

.region-tag {
    padding: 6px 12px;
    border-radius: 20px;
    font-size: 0.85rem;
    font-weight: 600;
}

.region-tag.positive {
    background: rgba(22, 163, 74, 0.12);
    color: var(--success);
    border: 1px solid rgba(22, 163, 74, 0.25);
}

.region-tag.negative {
    background: rgba(220, 38, 38, 0.1);
    color: var(--danger);
    border: 1px solid rgba(220, 38, 38, 0.25);
}

/* ===== Graph Container ===== */
.graph-container {
    margin-top: 24px;
    padding: 20px;
    background: var(--gray-50);
    border-radius: var(--radius-md);
    border: 1px solid var(--gray-200);
    animation: fadeIn 0.4s ease;
}

.graph-title {
    font-size: 1rem;
    font-weight: 600;
    color: var(--gray-700);
    margin-bottom: 16px;
    text-align: center;
}

#idmtChart,
#regionChart {
    max-height: 350px;
}

.coordinate-graph-wrapper {
    background: var(--white);
    border-radius: var(--radius-sm);
    padding: 15px;
    border: 1px solid var(--gray-200);
}

.graph-legend {
    margin-top: 12px;
    padding-top: 12px;
    border-top: 1px solid var(--gray-200);
}

.legend-items {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: 10px;
}

.legend-note {
    font-size: 0.75rem;
    color: var(--gray-500);
    text-align: center;
    font-style: italic;
    display: flex;
    align-items: center;
    justify-content: center;
    flex-wrap: wrap;
    gap: 5px;
}

/* ===== Fault Type Label ===== */
.fault-type-label {
    text-align: center;
    font-size: 0.85rem;
    font-weight: 600;
    color: var(--primary);
    background: rgba(99, 102, 241, 0.1);
    padding: 8px 16px;
    border-radius: var(--radius-sm);
    margin-bottom: 12px;
    border: 1px solid rgba(99, 102, 241, 0.2);
}

/* ===== Footer ===== */
.footer {
    text-align: center;
    padding: 30px 0;
    color: var(--gray-500);
    font-size: 0.85rem;
}

/* ===== Responsive - Mobile First ===== */
@media (max-width: 600px) {
    .container {
        padding: 12px;
    }

    .header {
        padding: 20px 0;
    }

    .header h1 {
        font-size: 1.3rem;
    }

    .subtitle {
        font-size: 0.85rem;
    }

    .calc-type-selector {
        gap: 8px;
        padding: 6px;
    }

    .calc-type-btn {
        flex-direction: column;
        gap: 4px;
        padding: 10px 8px;
        font-size: 0.8rem;
    }

    .btn-icon {
        font-size: 1.1rem;
    }

    .card {
        padding: 16px;
        border-radius: 16px;
    }

    .card-header h2 {
        font-size: 1.1rem;
    }

    .select-wrapper {
        margin-bottom: 14px;
    }

    .field-label {
        font-size: 0.75rem;
        margin-bottom: 6px;
    }

    select,
    input[type="number"] {
        padding: 12px 14px;
        font-size: 0.95rem;
    }

    .phase-info {
        flex-direction: column;
        gap: 8px;
    }

    .phase-badge {
        justify-content: center;
        padding: 8px 14px;
        font-size: 0.85rem;
    }

    .calculate-btn {
        padding: 14px 20px;
        font-size: 0.95rem;
    }

    .result-box {
        margin-top: 16px;
    }

    .result-box:not(:empty) {
        padding: 14px;
    }

    .result-value {
        font-size: 1.1rem;
    }

    .phase-result-card {
        padding: 12px;
    }

    .phase-result-title {
        font-size: 0.85rem;
    }

    .region-tag {
        padding: 5px 10px;
        font-size: 0.8rem;
    }

    .graph-container {
        margin-top: 16px;
        padding: 14px;
    }

    .graph-title {
        font-size: 0.9rem;
        margin-bottom: 12px;
    }

    #idmtChart,
    #regionChart {
        max-height: 280px;
    }

    .coordinate-graph-wrapper {
        padding: 10px;
    }

    .footer {
        padding: 20px 0;
        font-size: 0.75rem;
    }
}

@media (max-width: 360px) {
    .header h1 {
        font-size: 1.1rem;
    }

    .calc-type-btn {
        padding: 8px 6px;
        font-size: 0.75rem;
    }

    .card {
        padding: 12px;
    }

    select,
    input[type="number"] {
        padding: 10px 12px;
        font-size: 0.9rem;
    }
}