/* ==========================================================================
   BASE STYLES
   ========================================================================== */

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

:root {
    --color-primary: #2563EB;
    --color-primary-dark: #1D4ED8;
    --color-primary-darker: #1E40AF;
    --color-error: #ff4d4f;
    --color-error-dark: #ff1f1f;
    --color-warning: #e8a735;
    --color-warning-bg: #fef3cd;
    --color-warning-border: #f5d77d;

    --bg-gradient: linear-gradient(135deg, #0f172a 0%, #1e293b 50%, #0f172a 100%);
    --primary-gradient: linear-gradient(135deg, var(--color-primary) 0%, #3B82F6 100%);
    --result-gradient: linear-gradient(135deg, #eff6ff 0%, #dbeafe 100%);

    --border-color: #e8ecef;
    --border-color-hover: #93c5fd;

    --radius-sm: 10px;
    --radius-md: 12px;
    --radius-lg: 14px;
    --radius-xl: 16px;
    --radius-2xl: 24px;

    --spacing-sm: 12px;
    --spacing-md: 20px;
    --spacing-lg: 24px;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Inter', 'SF Pro Display', 'Segoe UI', sans-serif;
    background: var(--bg-gradient);
    background-attachment: fixed;
    color: #1a1a1a;
    padding: 60px 20px;
    min-height: 100vh;
    position: relative;
}

body::before {
    content: '';
    position: fixed;
    inset: 0;
    background-image:
        radial-gradient(circle at 20% 30%, rgba(37, 99, 235, 0.15) 0%, transparent 50%),
        radial-gradient(circle at 80% 70%, rgba(59, 130, 246, 0.1) 0%, transparent 50%),
        radial-gradient(circle at 50% 50%, rgba(37, 99, 235, 0.05) 0%, transparent 70%),
        url("data:image/svg+xml,%3Csvg width='60' height='60' viewBox='0 0 60 60' xmlns='http://www.w3.org/2000/svg'%3E%3Cg fill='none' fill-rule='evenodd'%3E%3Cg fill='%23ffffff' fill-opacity='0.03'%3E%3Cpath d='M36 34v-4h-2v4h-4v2h4v4h2v-4h4v-2h-4zm0-30V0h-2v4h-4v2h4v4h2V6h4V4h-4zM6 34v-4H4v4H0v2h4v4h2v-4h4v-2H6zM6 4V0H4v4H0v2h4v4h2V6h4V4H6z'/%3E%3C/g%3E%3C/g%3E%3C/svg%3E");
    pointer-events: none;
    z-index: 0;
}

.container {
    max-width: 700px;
    margin: 0 auto;
    display: flex;
    flex-direction: column;
    gap: 10px;
    position: relative;
    z-index: 1;
}

/* ==========================================================================
   TYPOGRAPHY
   ========================================================================== */

h1 {
    text-align: center;
    color: #ffffff;
    margin: 0;
    font-size: 2.8em;
    font-weight: 800;
    letter-spacing: -1.5px;
    text-shadow: 0 2px 10px rgba(37, 99, 235, 0.4);
}

.subtitle {
    text-align: center;
    color: #93c5fd;
    font-size: 1.2em;
    font-weight: 600;
    letter-spacing: 0.5px;
    opacity: 0.9;
    margin-bottom: 10px;
}

/* ==========================================================================
   CALCULATOR WRAPPER
   ========================================================================== */

.calculator-wrapper {
    background-color: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    border-radius: var(--radius-2xl);
    box-shadow: 0 8px 32px rgba(0, 0, 0, 0.2), 0 0 0 1px rgba(255, 255, 255, 0.1);
    overflow: hidden;
    border: 1px solid rgba(37, 99, 235, 0.1);
}

/* ==========================================================================
   SETUP GRID (Dropdowns)
   ========================================================================== */

.setup-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--spacing-md);
    padding: var(--spacing-lg);
}

.select-group {
    display: flex;
    flex-direction: column;
    gap: 8px;
}

.select-group.full-width {
    grid-column: 1 / -1;
}

.select-group label {
    color: var(--color-primary);
    font-weight: 700;
    font-size: 0.85em;
    text-transform: uppercase;
    letter-spacing: 0.8px;
}

.select-group select {
    width: 100%;
    padding: 12px 16px;
    border: 2px solid var(--border-color);
    border-radius: var(--radius-md);
    font-size: 15px;
    font-weight: 600;
    color: #1a1a1a;
    background-color: #fafbfc;
    cursor: pointer;
    appearance: none;
    background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='8' viewBox='0 0 12 8'%3E%3Cpath fill='%232563EB' d='M1.41 0L6 4.58 10.59 0 12 1.41l-6 6-6-6z'/%3E%3C/svg%3E");
    background-repeat: no-repeat;
    background-position: right 16px center;
    transition: border-color 0.2s ease, background-color 0.2s ease, box-shadow 0.2s ease;
}

.select-group select:hover {
    background-color: #fff;
    border-color: var(--border-color-hover);
}

.select-group select:focus {
    outline: none;
    border-color: var(--color-primary);
    background-color: #fff;
    box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.12);
}

/* ==========================================================================
   RESULT SECTION
   ========================================================================== */

.result-section {
    background: var(--result-gradient);
    padding: var(--spacing-lg);
    margin: 0 var(--spacing-lg) var(--spacing-lg);
    border-radius: var(--radius-xl);
    border: 2px solid rgba(37, 99, 235, 0.12);
}

.speed-display {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 4px;
    margin-bottom: var(--spacing-md);
}

.speed-label {
    color: var(--color-primary);
    font-weight: 600;
    font-size: 0.9em;
    text-transform: uppercase;
    letter-spacing: 0.8px;
}

.speed-value {
    color: var(--color-primary);
    font-weight: 900;
    font-size: 4.5em;
    letter-spacing: -3px;
    line-height: 1;
}

.speed-unit {
    color: var(--color-primary-dark);
    font-weight: 700;
    font-size: 1.3em;
    opacity: 0.7;
}

/* ==========================================================================
   WARNING
   ========================================================================== */

.warning {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    background-color: var(--color-warning-bg);
    border: 2px solid var(--color-warning-border);
    border-radius: var(--radius-md);
    padding: 14px 18px;
    margin-bottom: var(--spacing-md);
}

.warning.hidden {
    display: none;
}

.warning-icon {
    font-size: 1.5em;
    flex-shrink: 0;
}

.warning-text {
    color: #856404;
    font-weight: 700;
    font-size: 0.95em;
    line-height: 1.4;
}

/* ==========================================================================
   BREAKDOWN
   ========================================================================== */

.breakdown {
    border-top: 2px solid rgba(37, 99, 235, 0.1);
    padding-top: var(--spacing-md);
}

.breakdown-title {
    color: var(--color-primary);
    font-weight: 700;
    font-size: 0.85em;
    text-transform: uppercase;
    letter-spacing: 0.8px;
    margin-bottom: var(--spacing-sm);
}

.breakdown-row {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 8px 0;
    border-bottom: 1px solid rgba(37, 99, 235, 0.08);
    font-size: 0.95em;
}

.breakdown-row:last-child {
    border-bottom: none;
}

.breakdown-row span:first-child {
    color: #555;
    font-weight: 500;
}

.breakdown-row span:last-child {
    color: var(--color-primary);
    font-weight: 700;
    font-family: 'SF Mono', 'Fira Code', monospace;
}

.breakdown-total {
    border-top: 2px solid rgba(37, 99, 235, 0.15);
    border-bottom: none;
    margin-top: 4px;
    padding-top: var(--spacing-sm);
}

.breakdown-total span:first-child {
    color: var(--color-primary);
    font-weight: 800;
}

.breakdown-total span:last-child {
    font-size: 1.2em;
    font-weight: 900;
}

/* ==========================================================================
   RECOMMENDATIONS
   ========================================================================== */

.recommendations {
    background-color: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    border-radius: var(--radius-2xl);
    box-shadow: 0 8px 32px rgba(0, 0, 0, 0.2), 0 0 0 1px rgba(255, 255, 255, 0.1);
    border: 1px solid rgba(37, 99, 235, 0.1);
    padding: var(--spacing-lg) var(--spacing-lg) var(--spacing-md);
    text-align: center;
}

.recommendations-title {
    color: var(--color-primary);
    font-weight: 700;
    font-size: 0.85em;
    text-transform: uppercase;
    letter-spacing: 0.8px;
    margin-bottom: var(--spacing-sm);
}

.rec-input-wrapper {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 10px;
    margin-bottom: var(--spacing-md);
}

.rec-input-wrapper input {
    width: 150px;
    padding: 16px 20px;
    border: 2px solid var(--border-color);
    border-radius: var(--radius-lg);
    font-size: 2.4em;
    font-weight: 700;
    color: #1a1a1a;
    background-color: #fafbfc;
    text-align: center;
    transition: border-color 0.2s ease, background-color 0.2s ease, box-shadow 0.2s ease;
    -moz-appearance: textfield;
}

.rec-input-wrapper input::-webkit-outer-spin-button,
.rec-input-wrapper input::-webkit-inner-spin-button {
    -webkit-appearance: none;
    margin: 0;
}

.rec-input-wrapper input:hover {
    background-color: #fff;
    border-color: var(--border-color-hover);
}

.rec-input-wrapper input:focus {
    outline: none;
    border-color: var(--color-primary);
    background-color: #fff;
    box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.12);
}

.rec-input-unit {
    color: var(--color-primary);
    font-weight: 700;
    font-size: 1.4em;
}

.rec-placeholder {
    color: #93c5fd;
    font-size: 0.9em;
    font-weight: 500;
    padding: var(--spacing-sm) 0;
}

.rec-card {
    text-align: left;
    background-color: #f8fafc;
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    padding: var(--spacing-md);
}

.rec-speed-badge {
    background: var(--primary-gradient);
    color: #fff;
    font-weight: 800;
    font-size: 0.85em;
    padding: 5px 14px;
    border-radius: var(--radius-sm);
    display: inline-block;
    margin-bottom: var(--spacing-sm);
}

.rec-setups {
    display: flex;
    flex-direction: column;
    gap: 10px;
}

.rec-setup {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: var(--spacing-md);
    background-color: #fff;
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    padding: 12px 16px;
}

.rec-setup-details {
    display: flex;
    flex-direction: column;
    gap: 2px;
    font-size: 0.9em;
    color: #555;
}

.rec-setup-details strong {
    color: #1a1a1a;
    font-weight: 700;
}

.rec-apply-btn {
    background: var(--primary-gradient);
    color: #fff;
    border: none;
    border-radius: var(--radius-sm);
    padding: 10px 22px;
    font-size: 0.88em;
    font-weight: 700;
    cursor: pointer;
    white-space: nowrap;
    flex-shrink: 0;
    transition: filter 0.15s ease, transform 0.1s ease;
}

.rec-apply-btn:hover {
    filter: brightness(1.1);
}

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

/* ==========================================================================
   RESPONSIVE DESIGN
   ========================================================================== */

@media (max-width: 600px) {
    body {
        padding: 16px 8px;
    }

    .container {
        gap: 6px;
    }

    h1 {
        font-size: 1.8em;
    }

    .subtitle {
        font-size: 0.95em;
        margin-bottom: 6px;
    }

    .calculator-wrapper {
        border-radius: 16px;
    }

    .setup-grid {
        grid-template-columns: 1fr;
        gap: 10px;
        padding: 16px;
    }

    .select-group.full-width {
        grid-column: 1;
    }

    .select-group label {
        font-size: 0.8em;
    }

    .select-group select {
        padding: 12px 14px;
        font-size: 16px;
        min-height: 48px;
        border-radius: 10px;
    }

    .result-section {
        margin: 0 10px 10px;
        padding: 16px;
        border-radius: 12px;
    }

    .speed-label {
        font-size: 0.78em;
    }

    .speed-value {
        font-size: 3em;
    }

    .speed-unit {
        font-size: 1em;
    }

    .warning {
        padding: 10px 14px;
        gap: 8px;
    }

    .warning-text {
        font-size: 0.85em;
    }

    .breakdown-title {
        font-size: 0.8em;
    }

    .breakdown-row {
        font-size: 0.85em;
        padding: 6px 0;
    }

    .breakdown-total span:last-child {
        font-size: 1.1em;
    }

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

    .rec-input-wrapper input {
        font-size: 1.8em;
        width: 120px;
    }

    .rec-setup {
        flex-direction: column;
        align-items: flex-start;
        gap: 8px;
        padding: 10px 12px;
    }

    .rec-apply-btn {
        width: 100%;
        text-align: center;
        padding: 10px;
    }
}

@media (max-width: 380px) {
    body {
        padding: 10px 4px;
    }

    h1 {
        font-size: 1.5em;
    }

    .setup-grid {
        padding: 12px;
        gap: 8px;
    }

    .result-section {
        margin: 0 8px 8px;
        padding: 12px;
    }

    .speed-value {
        font-size: 2.5em;
    }
}