/* ========================================
   Result Percentage Calculator Styles
   Responsive: PC & Mobile
======================================== */

:root {
    --primary: #6366f1;
    --primary-dark: #4f46e5;
    --primary-light: #818cf8;
    --success: #22c55e;
    --warning: #f59e0b;
    --danger: #ef4444;
    --dark: #1e1b4b;
    --gray-50: #f9fafb;
    --gray-100: #f3f4f6;
    --gray-200: #e5e7eb;
    --gray-300: #d1d5db;
    --gray-400: #9ca3af;
    --gray-500: #6b7280;
    --gray-600: #4b5563;
    --gray-700: #374151;
    --gray-800: #1f2937;
    --gray-900: #111827;
    --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.05);
    --shadow: 0 1px 3px 0 rgb(0 0 0 / 0.1), 0 1px 2px -1px rgb(0 0 0 / 0.1);
    --shadow-md: 0 4px 6px -1px rgb(0 0 0 / 0.1), 0 2px 4px -2px rgb(0 0 0 / 0.1);
    --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.1), 0 4px 6px -4px rgb(0 0 0 / 0.1);
    --radius: 12px;
    --radius-sm: 8px;
}

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

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    background: #ffffff;
    color: var(--gray-800);
    line-height: 1.5;
    -webkit-font-smoothing: antialiased;
}

.page-wrapper {
    max-width: 1200px;
    margin: 0 auto;
    padding: 24px 16px 48px;
}

/* Header */
.page-header {
    text-align: center;
    margin-bottom: 32px;
}

.page-header h1 {
    font-size: 1.75rem;
    font-weight: 700;
    color: var(--primary);
    margin-bottom: 4px;
}

.subtitle {
    color: var(--gray-500);
    font-size: 0.875rem;
}

/* Grid Layout */
.main-grid {
    display: grid;
    grid-template-columns: 360px 1fr;
    gap: 24px;
    align-items: start;
}

.left-column,
.right-column {
    display: flex;
    flex-direction: column;
    gap: 20px;
}

/* Cards */
.card {
    background: #ffffff;
    border: 1px solid var(--gray-200);
    border-radius: var(--radius);
    padding: 20px;
    box-shadow: var(--shadow-sm);
}

.card-title {
    font-size: 1rem;
    font-weight: 600;
    color: var(--gray-800);
    margin-bottom: 16px;
    padding-bottom: 12px;
    border-bottom: 1px solid var(--gray-100);
}

.card-title.light {
    color: #ffffff;
    border-bottom-color: rgba(255,255,255,0.2);
    text-align: center;
}

/* Form Elements */
.form-group {
    margin-bottom: 14px;
}

.form-group label {
    display: block;
    font-size: 0.8rem;
    font-weight: 500;
    color: var(--gray-700);
    margin-bottom: 6px;
}

.form-group input[type="text"],
.form-group input[type="number"] {
    width: 100%;
    padding: 10px 12px;
    border: 1px solid var(--gray-200);
    border-radius: var(--radius-sm);
    font-size: 0.9rem;
    font-family: inherit;
    color: var(--gray-800);
    background: #fff;
    transition: border-color 0.15s, box-shadow 0.15s;
}

.form-group input:focus {
    outline: none;
    border-color: var(--primary-light);
    box-shadow: 0 0 0 3px rgba(99, 102, 241, 0.1);
}

.form-group input::placeholder {
    color: var(--gray-400);
}

/* Grade Inputs */
.hint-text {
    font-size: 0.75rem;
    color: var(--gray-500);
    margin-bottom: 12px;
}

.grade-inputs {
    display: flex;
    flex-direction: column;
    gap: 10px;
}

.grade-row {
    display: flex;
    align-items: center;
    gap: 8px;
}

.grade-label {
    width: 28px;
    font-weight: 600;
    font-size: 0.85rem;
    color: var(--gray-700);
}

.grade-input {
    flex: 1;
    padding: 8px 10px;
    border: 1px solid var(--gray-200);
    border-radius: var(--radius-sm);
    font-size: 0.9rem;
    text-align: left;
}

.grade-input:focus {
    outline: none;
    border-color: var(--primary-light);
}

.grade-suffix {
    font-size: 0.75rem;
    color: var(--gray-500);
    width: 48px;
}

/* Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 10px 20px;
    border: none;
    border-radius: var(--radius-sm);
    font-size: 0.875rem;
    font-weight: 500;
    font-family: inherit;
    cursor: pointer;
    transition: all 0.15s;
    text-decoration: none;
}

.btn-primary {
    background: var(--primary);
    color: #fff;
}

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

.btn-dark {
    background: var(--gray-800);
    color: #fff;
}

.btn-dark:hover {
    background: var(--gray-900);
}

.btn-secondary {
    background: var(--gray-100);
    color: var(--gray-700);
}

.btn-secondary:hover {
    background: var(--gray-200);
}

.btn-danger {
    background: #fee2e2;
    color: var(--danger);
}

.btn-danger:hover {
    background: #fecaca;
}

.btn-full {
    width: 100%;
}

.btn-delete {
    padding: 4px 12px;
    background: #fee2e2;
    color: var(--danger);
    border: none;
    border-radius: 6px;
    font-size: 0.75rem;
    font-weight: 500;
    cursor: pointer;
    transition: background 0.15s;
}

.btn-delete:hover {
    background: #fecaca;
}

/* Table */
.table-wrapper {
    overflow-x: auto;
}

.subject-table {
    width: 100%;
    border-collapse: collapse;
    font-size: 0.85rem;
}

.subject-table thead th {
    text-align: left;
    padding: 10px 8px;
    color: var(--gray-500);
    font-weight: 500;
    font-size: 0.7rem;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    border-bottom: 1px solid var(--gray-100);
}

.subject-table tbody td {
    padding: 12px 8px;
    border-bottom: 1px solid var(--gray-50);
    color: var(--gray-700);
}

.subject-table tbody tr:last-child td {
    border-bottom: none;
}

.subject-name {
    font-weight: 500;
    color: var(--gray-800);
}

.percentage {
    font-weight: 600;
}

.pct-high { color: var(--success); }
.pct-mid  { color: var(--warning); }
.pct-low  { color: var(--danger); }

.empty-state {
    text-align: center;
    padding: 32px 16px;
    color: var(--gray-400);
    font-size: 0.875rem;
    display: none;
}

/* Result Card */
.result-card {
    background: linear-gradient(135deg, #6366f1 0%, #4f46e5 100%);
    border: none;
    color: #fff;
}

.result-content {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 12px;
}

.grade-display {
    font-size: 3rem;
    font-weight: 700;
    line-height: 1;
}

.grade-ap { color: #fcd34d; }
.grade-a  { color: #fde047; }
.grade-b  { color: #bef264; }
.grade-c  { color: #fdba74; }
.grade-d  { color: #fca5a5; }
.grade-f  { color: #ef4444; }

.pass-badge {
    display: inline-block;
    padding: 4px 14px;
    border-radius: 4px;
    font-size: 0.75rem;
    font-weight: 600;
    letter-spacing: 0.05em;
    background: rgba(255,255,255,0.25);
    color: #fff;
}

.pass-badge.pass {
    background: rgba(34, 197, 94, 0.9);
}

.pass-badge.fail {
    background: rgba(239, 68, 68, 0.9);
}

.performance-text {
    font-size: 0.875rem;
    opacity: 0.9;
    font-style: italic;
    text-align: center;
}

/* Stats Grid */
.stats-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 12px;
    width: 100%;
    margin: 8px 0;
}

.stat-box {
    background: #ffffff;
    border-radius: var(--radius-sm);
    padding: 14px 8px;
    text-align: center;
    box-shadow: var(--shadow-sm);
}

.stat-label {
    font-size: 0.7rem;
    color: var(--gray-500);
    text-transform: uppercase;
    letter-spacing: 0.03em;
    margin-bottom: 4px;
}

.stat-value {
    font-size: 1rem;
    font-weight: 700;
    color: var(--gray-800);
}

/* Overlays */
.overlay {
    position: fixed;
    inset: 0;
    background: rgba(0, 0, 0, 0.5);
    backdrop-filter: blur(4px);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 1000;
    padding: 16px;
    opacity: 1;
    transition: opacity 0.2s;
}

.overlay.hidden {
    display: none;
    opacity: 0;
}

.overlay-panel {
    background: #ffffff;
    border-radius: var(--radius);
    padding: 28px 24px;
    max-width: 360px;
    width: 100%;
    text-align: center;
    box-shadow: var(--shadow-lg);
    animation: slideUp 0.25s ease-out;
}

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

.overlay-icon {
    width: 48px;
    height: 48px;
    border-radius: 50%;
    background: var(--success);
    color: #fff;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.5rem;
    font-weight: 700;
    margin: 0 auto 16px;
}

.overlay-icon.warning {
    background: var(--warning);
}

.overlay-icon.error {
    background: var(--danger);
}

.overlay-panel h3 {
    font-size: 1.1rem;
    font-weight: 600;
    margin-bottom: 6px;
    color: var(--gray-800);
}

.overlay-panel p {
    color: var(--gray-500);
    font-size: 0.875rem;
    margin-bottom: 20px;
}

.overlay-actions {
    display: flex;
    gap: 10px;
    justify-content: center;
}

.overlay-actions .btn {
    flex: 1;
}

/* Loading Panel */
.loading-panel {
    padding: 32px;
}

.spinner {
    width: 40px;
    height: 40px;
    border: 3px solid var(--gray-200);
    border-top-color: var(--primary);
    border-radius: 50%;
    animation: spin 0.8s linear infinite;
    margin: 0 auto 16px;
}

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

/* ========================================
   Responsive: Mobile
======================================== */

@media (max-width: 900px) {
    .main-grid {
        grid-template-columns: 1fr;
    }

    .left-column {
        order: 2;
    }

    .right-column {
        order: 1;
    }

    .stats-grid {
        grid-template-columns: repeat(2, 1fr);
    }

    .page-header h1 {
        font-size: 1.4rem;
    }
}

@media (max-width: 480px) {
    .page-wrapper {
        padding: 16px 12px 32px;
    }

    .card {
        padding: 16px;
    }

    .grade-label {
        width: 24px;
        font-size: 0.8rem;
    }

    .grade-suffix {
        font-size: 0.7rem;
        width: 40px;
    }

    .subject-table {
        font-size: 0.8rem;
    }

    .subject-table thead th,
    .subject-table tbody td {
        padding: 8px 6px;
    }

    .grade-display {
        font-size: 2.5rem;
    }

    .stat-box {
        padding: 10px 6px;
    }

    .stat-value {
        font-size: 0.9rem;
    }
}